Fleitz Continuing Education Jeana Fleitz, M.E.D., RT(R)(M)

“The X-Ray Lady” 6511 Glenridge Park Place, Suite 6

Louisville, KY 40222 Telephone (502) 425-0651

Fax (502) 327-7921 Website www.x-raylady.com

Email address xrayladyce@gmail.com

Radiation Safety For the Female Patient

Approved for 3 Category A+ CE Credit

American Society of Radiologic Technologists (ASRT) Approved for 3 Category A+ CE Credits Course Approval Start Date 01/01/2014 Course Approval End Date 02/01/2018

Florida Radiologic Technology Program FLDOH-BRC Approved for 3 Category A CE Credits (00 –Technical)

Course Approval Start Date 12/03/2013 Course Approval End Date 01/31/2016

Please call our office before the course approval end date for course renewal status. Please let us know if your mailing address or email address changes. Thank you.

A Continuing Education Course for Radiation Operators

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X-Ray Lady CE®

Jeana Fleitz, M.Ed., RT(R)(M) 6511 Glenridge Park Place, Suite 6 Louisville, KY 40222 Phone: (502) 425-0651 | Email: xrayladyce@gmail.com

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X-Ray Lady CE®

Jeana Fleitz, M.Ed., RT(R)(M) 6511 Glenridge Park Place, Suite 6 Louisville, KY 40222 Phone: (502) 425-0651 | Email: xrayladyce@gmail.com

Website: www.x-raylady.com

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Jeana Fleitz, M.Ed., RT(R)(M) 6511 Glenridge Park Place, Suite 6 Louisville, KY 40222 Phone: (502) 425-0651 | Email: xrayladyce@gmail.com

Website: www.x-raylady.com

Radiation Safety for the Female Patient Approved for 3 Category A+ CE Credits

Course Description

The female patient has gender characteristics that pose unique challenges to radiographers in implementing radiation safety measures. Pregnancy, radiosensitive breast tissue, lactation, and an inability to easily exclude the ovaries from the area of clinical interest pose the major issues. Thus, women have particular vulnerabilities to ionizing radiation that are different from those encountered by males. In childhood, females are more susceptible to radiation than males, primarily due to superficial and dormant breast tissue. In the reproductive years the focus of attention is on preventing radiation exposure to the conceptus/fetus. Delivery of medical imaging services to females requires that radiographers have an understanding of women’s particular health issues, challenges and disparities. This course provides an overview of these issues and the rationale and implementation of radiation safety for the female patient during medical imaging. The radiographer will also be introduced to the most recent guidelines for imaging pregnant or potentially pregnant adolescents and women with ionizing radiation

Objectives Upon completion of this course, the participant will: 1. Recognize female characteristics that make them more vulnerable to the ionizing

radiation. 2. Understand women’s health disparities that are not only gender-based but also

associated with factors such as age, disability, education, ethnicity, geographic location, income, or race.

3. Identify how the availability of image-guided minimally invasive procedures has influenced the management of a wide range of women’s health issues.

4. State known facts about medical imaging decision support tools published by the American College of Radiology.

5. Given frequently asked questions about pregnancy and radiation safety, correctly identify the answer developed by the International Atomic Energy Association.

6. Recall facts about radiation, its description and sources. 7. Differentiate between deterministic and stochastic effects of radiation and give examples

of each. 8. Understand the scope and depth of radiation doses on the conceptus/fetus. 9. Identify examination specific strategies used to reduce radiation dose and exposure. 10. Explain the use of the dose registry in radiation safety of the female patient. 11. List the purpose of the American College of Radiology ACR-SPR Practice Guideline for

Imaging Pregnant or Potentially Pregnant Adolescents and Women with Ionizing Radiation.

12. State known facts about the radiation risks to the fetus. 13. Recognize common examples of screening for pregnancy. 14. Apply procedures for imaging the pregnant patient to include patient consent,

preplanning, and counseling. 15. Review examples provided by the ACR of consent form and pregnancy screening

recommendations.

1

2

Radiation Safety for the Female Patient

Introduction

The female patient has gender characteristics that pose unique challenges to

radiologists and radiographers in implementing radiation safety measures. The major issues

are posed by pregnancy, radiosensitive breast tissue, lactation, and an inability to easily exclude

the ovaries from the area of clinical interest. Thus, women have particular vulnerabilities to

ionizing radiation that are different from those encountered with males. In childhood, females

are more susceptible to radiation than males, primarily due to superficial and dormant breast

tissue. In the reproductive years the focus of attention is on preventing radiation exposure to

the conceptus/fetus. Delivery of medical imaging services to females requires that

radiographers have an understanding of women’s particular health issues, challenges and

disparities. This course provides radiographers with an overview of these issues and the

rationale and implementation of radiation safety for the female patient during medical imaging.

Radiographers will also be introduced to the most recent guidelines for imaging pregnant or

potentially pregnant adolescents and women with ionizing radiation.

Gender Related Disease Differences

In a research study conducted by Brittle and Bird for the Office on Women’s Health, data

showed how disease may differ between the sexes.1 Specifically, the data indicated that there

are more general differences that demonstrate how gender impacts the relationship between

female patients and the healthcare system.1 For example, the study found that women utilize the

healthcare system more often than men, primarily due to their higher use of preventive service.1

This however was found to not equate to better care of acute conditions in women.1 Over the

past few decades, considerable progress has been made in improving women’s health and in

understanding women’s unique needs in the healthcare system. To better understand the

issues facing women, the Kaiser Family Foundation conducted surveys in 2001 and again in

2004. Some of the key findings are listed in Figure 1.

Women’s health needs and healthcare utilization patterns change and evolve as they age;

Most women in the U.S. are in good health with 8 in 10 reporting excellent, very good, or

good health. However, a sizable minority, nearly 1 in 5 (19%), are in fair or poor health.

This proportion increases with age, to nearly one-third of women 65 or older;

3

Nearly 4 in 10 women (38%), have a chronic condition that requires ongoing medical

attention, compared to 30% of men;

Many younger women also have chronic health problems;

Health coverage, private or public, matters for women, yet it does not guarantee access to

healthcare;

Healthcare costs are increasingly acting as a barrier to healthcare for many women;

Certain population of women experience higher rates of health problems and more barriers

in accessing healthcare;

Women who are sick face more obstacles in obtaining healthcare;

Doctor-patient counseling about health risks and health promoting behaviors is lagging; and,

Women are the healthcare leaders for their families.2

Fig.1. Key findings from the Kaiser women’s health survey. Retrieved from http://kaiserfamily foundation.files.wordpress.com/2013/01-women-and-health-care-a-national-profile-key-findings-from the kaiser-women-health-survey-report-highlights.pdf. on September 19, 2013.

In a report brief by the Institute of Medicine (IOM) of the National Academies it was found that

“even though slightly over half of the U.S. population is female, apart from reproductive

concerns, medical research historically has neglected the health needs of women.”3 The report

indicated that women’s health research has contributed to significant progress in addressing

some conditions, while other conditions have seen only moderate progress or even little or no

progress over the past 20 years.3 Historically, women have not participated in clinical trials as

often as men and it is not really known if medical treatments are as appropriate for women as

they are for men.4 In the U.S., 1 in 4 women dies from heart disease with the most common

cause in both men and women being narrowing or blockage of the coronary arteries.4 Heart

diseases that affect women more than men include coronary microvascular disease and broken

heart syndrome, caused by an extreme emotional stress leading to severe but often short-term

heart muscle failure.4

Gender-based System of Healthcare

The previously mentioned research findings have led to a growing movement toward a

more gender-based system of healthcare. Data from a study evaluating recent changes in

cardiovascular risk factors among women and men list the following examples of gender-related

differences in health, Figure 2.

Before menopause, women have lower blood pressure than men do. After menopause,

systolic blood pressure in women is higher than in men;

4

Women with peripheral arterial disease are at greater risk for a compromise in daily function

and quality of life than are men;

Women are more likely than are men to experience coronary vascular injury and bleeding

complications after percutaneous coronary intervention;

Women have more advanced disease than men do when colon cancer is first diagnosed;

Women are at a significantly higher risk for autoimmune disease than are men;

Men experience more deaths due to cancer than women do (57% to 43%);

Thyroid cancers are more prevalent in women than they are in men;

Women with Alzheimer disease are more likely to exhibit severe cognitive impairment than

do men; and,

Women have a later age of onset of schizophrenia than do men.4

Fig. 2. Gender-related differences in health. Kim JK, Alley D, Seeman T, Karlamangla A, Crimmins E. Recent changes in cardiovascular risk factors among women and men. J Women’s Health (Larchmt) 2006;15:734-746.

Health Disparities

Nationally, one-third of women self-identify as a member of a racial or ethnic minority

group and it are estimated that this share will increase to more than half by 2045.5 The

distribution of the population of women of color varies substantially by state. As the country

becomes more racially and ethnically diverse, understanding racial and ethnic disparities in

health status and access to care has become a higher priority for many policymakers,

researchers, and advocacy groups. There is also a growing recognition that problems differ

geographically and effective solutions will need to address these challenges at federal, state,

and local levels.

Women face health disparities that are not only gender-based but also associated with

factors such as age, disability, education, ethnicity, geographic location, income, or race.

The first attempt at an official definition for “health disparities” was developed in September

1999, in response to a White House initiative. The National Institutes of Health (NIH), under the

leadership of then-director, Dr. Harold Varmus, convened a NIH-wide working group, charged

with developing a strategic plan for reducing health disparities. That group developed the first

NIH definition of “health disparities”, which states that health disparities are differences in the

incidence, prevalence, mortality, and burden of diseases and other adverse health conditions

that exist among specific population groups in the U.S.6

In 2000, U.S. Public Law 106-525, also known as the “Minority Health and Health

Disparities Research and Education Act”, authorized the creation of the National Center for

5

Minority Health and Health Disparities and provided a legal definition of health disparities: “ The

law characterized a population as a health disparity population if there is a significant disparity in

the overall rate of disease incidence, prevalence, morbidity, mortality or survival rates in the

population as compared to the health status of the general population.”6 Age, disability,

education, ethnicity, gender, geographic location, income, or race may characterize these

population groups. People who are poor, lack health insurance, and are medically underserved

(i.e., have limited or no access to effective healthcare) regardless of ethnic and racial

background often bear a greater burden of disease than the general population.

In the U.S., the Office of Management and Budget (OMB), defines racial and ethnic

minority populations for purposes of gathering census statistics and appropriating government

entitlements.7 These categories are used in healthcare settings as well as in schools,

government facilities and businesses. The OMB recognizes racial and ethnic populations as

American Indian, Alaska Native, and Asian, African American, Hispanic, Native Hawaiian, and

Pacific Islander, multiracial and White populations.6 It is important to recognize that within each

of the broad statistical categories there are numerous cultural groups. These groups are

characterized by variations in lifestyle, values and beliefs, health and illness related practices,

preference for care, and family member patterns of interaction.

Current literature supports the fact that racial and ethnic minority populations also

face cancer disparities. If one closely examines the NCI’s definition of cancer disparities, a

more encompassing understanding emerges of what constitutes a minority population. The

NCI’s definition includes those in “specific populations”, who suffer a greater disease incidence,

prevalence, and mortality due to certain conditions.8 Race and ethnicity certainly are factors in

health disparities; but others include lack of medical insurance coverage, those who are

homeless, people living in rural communities who lack access to healthcare, the elderly, the

disabled, and undocumented citizens (i.e., individuals who have entered the U.S. without legal

egress).

A close look at cancer incidence and death statistics reveals that certain groups in the

U.S. suffer disproportionately from cancer and its associated effects, including premature death.

For example, African Americans, Asians, Hispanics, American Indians, Alaska Natives, and

underserved Whites are more likely than the general population to have higher incidence and

death for certain types of cancer.9 When African American women are treated for breast

cancer, they may be less likely than White women to receive state-of-the-art diagnosis and

treatment.9 This may be influenced by the standard of care in the hospitals where they are

treated (i.e., smaller hospitals and clinics versus large hospitals and specialty cancer centers).

6

The health status among racial and ethnic groups have been studied and to date there are

some notable differences in health status between White women and women of color,

particularly African Americans. Figure 3 summarizes these differences.

Women of color are more likely to report that they are in fair or poor health;

African American women are more likely to have a physical condition that limits routine

activities such as participating in school, work, or daily housework;

Despite their reports of poor health status, Latinas are actually less likely to report that

they have a chronic condition in need of ongoing care;

Over half of African American women ages 45-64 have been diagnosed with

hypertension, twice the rate for White women;

African American women are also significantly more likely to have arthritis than Latinas

and White women; and

African American women are less likely to have osteoporosis compared to Latinas and

White women.

Fig.3. The Henry J. Kaiser Family Foundation. Issue Briefs. An update on women’s health policy. March 2004. Retrieved from http:kff.org on November 13, 2013.

10

Research also shows that individuals from medically underserved populations are more

likely to be diagnosed with late-stage diseases that might have been treated more effectively

or cured if diagnosed earlier.9 The Surveillance, Epidemiology, and End Results (SEER)

Program is NCI’s authoritative source for information about cancer incidence and survival

data from cancer registries and represent approximately 26% of the U.S. population. Over

several decades, SEER has worked to better represent racial, ethnic, and socioeconomic

diversity and currently covers 23% of African Americans, 40% of Hispanics, 42% of

American Indians and Alaska Natives, 53% of Asians, and 70% of Hawaiian/Pacific

Islanders living in the U.S.8 In addition, SEER statistics reflect the U.S. population in regard

to poverty and education, with both urban and rural groups represented. These statistics

are most often reported as the numbers of new cases of invasive cancer and cancer deaths

per year per 100,000 persons of that gender.9 In addition, the SEER statistics are age-

adjusted to the U.S. standard population. Age-adjustment is done because different

population groups may not be comparable with respect to age.

The Kaiser Family Foundation has published a report, Putting Women’s Health Care

Disparities on the Map”. The premise of this report is that health is shaped by many factors,

from biological to social and political. The Foundation asserts that to improve women’s

health it is critical to measure more than just the physical outcomes. The report also

7

provides new information about how women fare at the state level by assessing the status of

women in all 50 states and the District of Columbia. Key findings of the report are related to

3 dimensions; health status, access to and utilization of healthcare, and social determinants,

Figure 4.5

Disparities exist in every state. Women of color fared worse than White women

across a broad range of measures in almost every state, and in some states these

disparities were quite stark. Some of the largest disparities were in the rates of new

AIDS cases, later or no prenatal care, no insurance coverage, and lack of a high

school diploma.

In states where disparities appeared to be smaller, this difference was often due to

the fact that both White women and women of color were doing poorly in all 3 health

dimensions.

Few states had consistently high or low disparities across all 3 dimensions.

States with small disparities in access to care were not necessarily the same states

with small disparities in health status or social determinants.

Each racial and ethnic group faced its own particular set of health care challenges.

Fig.4. Executive Summary: Putting women’s health care disparities on the map. The Kaiser Family Foundation. 2013. Retrieved from http://kaiserfamilyfoundation.files.wordpress.com/2013/01/7886es.pdf on November 13 2013.

5

The Kaiser Family Foundation report highlighted specific healthcare challenges faced by

each racial and ethnic group. The report details the enormous health and socioeconomic

challenges that many American Indian and Alaska Native women face. This group of women

had higher rates of health and access roadblocks than women in other racial and ethnic groups

on several indicators, often twice as high as White women.5 It was found that one-third of

American Indian and Alaska Native women were uninsured or had not had a recent

mammogram.5 They also had considerably higher rates of utilization problems, such as not

having a recent checkup or Pap smear, or not getting early prenatal care.5 For Hispanic

women, access and utilization were consistent problems even though they fared better on some

health status indicators. A greater share of Latinas than other groups lacked insurance, did not

have a personal doctor/healthcare provider, and delayed or went without care because of cost.

African American women experienced consistently higher rates of health problems but at the

same time they also had the highest screening rate of all racial and ethnic groups. The data

showed that African American women had a consistent pattern of high rates of health

8

challenges, ranging from poor health status to chronic illnesses to obesity and cancer deaths.

The most striking disparity was the extremely high rate of new AIDS cases among African

American women.5 White women fared better than minority women on most indicators, but had

higher rates of some health and access problems than women of color. White women had

higher rates of smoking, cancer mortality, serious psychological distress, and no routine

checkup than women of color.5 Within a racial and ethnic group, the health experiences of

women often varied considerably by state.5

The U.S. is truly a melting pot of many diverse people who represent a multitude of

races, ethnicity, and culture. Females have unique healthcare issues but also their race, ethnic

status and culture influence these issues. Current literature supports the fact that racial and

ethnic minority populations face health disparities. Radiographers provide imaging services to

females in a variety of geographic locations and settings throughout the U.S. The women

served will represent a microcosm of the population and radiographers should be ready and

able to provide quality imaging and radiation safety to this diverse population.

Medical Imaging of the Female Patient

The availability of image-guided minimally invasive procedures has influenced the

management of a wide range of women’s health issues. Interventional radiology (IR) has

development a focus in women’s health during the past decade, leading to less invasive

treatment of many female conditions. An example is the use of IR techniques to treat uterine

leiomyoma with uterine artery embolization (UAE). The American College of Obstetrics and

Gynecology (ACOG) supports such minimally invasive treatment options and recommends that

physicians discuss these options with patients when explaining treatments. Leiomyoma, the

most common uterine neoplasm, is composed of smooth muscle with varying amounts of

fibrous connective tissue. Leiomyoma, also known as fibroids or myomas, are the most common

gynecologic neoplasm, occurring in 20%-30% of women of reproductive age.11 Leiomyoma

account for approximately 30% of all hysterectomies performed in the U.S; this figure is a high

as 50% among African American women.11 These fibrous growths are usually asymptomatic,

but a patient may present with abnormal uterine bleeding or related symptoms. Although 80%

of women with leiomyoma are asymptomatic, 20%-50% of women present with symptoms such

as menorrhagia, dysmenorrhea, pressure, urinary frequency, pelvic and back pain, dyspareunia,

constipation, or obstipation.11 Hysterectomy and myomectomy are the traditional surgical

treatments for symptomatic leiomyoma; however UFE is a popular and effective minimally

invasive treatment. As a percutaneous interventional technique, this procedure may offer the

9

advantages of avoidance of surgical risks, potential preservation of fertility, and shorter

hospitalization.

Percutaneous vascular embolization is a common interventional radiology treatment

option for a wide range of gynecologic and obstetric abnormalities. This therapeutic procedure

was established in the 1960s as a method for controlling arterial bleeding in the gastrointestinal

tract and at various sites of traumatic injury.12 Since then, embolization therapy has become

commonly used by interventional radiology specialists, who use various mechanical, chemical

and radioactive embolic devices introduced through a catheter to treat a broad range of

conditions, from benign vascular malformations to malignancies. Other examples include the

use of UAE to treat postpartum hemorrhage and in many situations, make it possible to avoid

hysterectomy.12 Other gynecologic conditions that are indicated for UAE include management of

ectopic pregnancy and a method to control pelvic bleeding due to coagulopathy or injury.

Fallopian tube recanalization is used to treat problems of infertility as well as ovarian vein

embolization to treat patients with pelvic congestion syndrome.

Radiologists and radiographers are frequently involved in treating complications of

assisted reproductive technology (ART). Many of these encounters may be associated with

complications of an emergency nature. Such complications include ovarian hyperstimulation

syndrome (OHSS), ovarian torsion, and ectopic and heterotopic pregnancy.13 During ART,

hyperstimulation can occur following ovulation induction or ovarian stimulation which manifests

with bilateral ovarian enlargement by multiple cysts, fluids and clinical findings ranging from

gastrointestinal discomfort to life-threatening renal failure and coagulopathy.13 Enlarged

hyperstimulated ovaries are at risk for torsion. There is also an increased risk for ectopic

pregnancy following ART, with a relative increased risk for rarer and more lethal forms, including

interstitial and cervical ectopic pregnancies. The use of multimodality imaging examinations

provide for accurate and timely diagnosis and help avert serious consequences.

Another gynecological interventional radiology procedure involves imaging of

mechanical tubal occlusion devices. Between 2006 and 2008, the leading methods of birth

control in the U.S, used by 21 million women, were oral contraceptives and tubal ligation.14

During the past decade, various mechanical devices, including transcervical tubal occlusion

systems have become an available means of achieving either reversible or permanent

contraception. Almost half a million kits for one permanent tubal occlusion system were

distributed worldwide from 2001 through 2010.14 These mechanical devices are generally

considered safe but tubal occlusion devices carry risks of complications and malfunctions.

Medical imaging studies are often used to verify adequate placement and functioning of these

10

devices. In the U.S., women receiving a mechanical tubal occlusion device are required to

undergo hysterosalpingography 3 months after the procedure.14 When complications associated

with the placement of these devices arise, radiologists and radiographers usually are involved in

obtaining images. Such complications include failure of tubal occlusion, device dislodgement

and migration, and tubal and uterine perforation.

Women are at greater risk of breast cancer than men. A woman living in the U.S. has a

12.3%, or a 1 in 8 lifetime risk of being diagnosed with breast cancer.15 In the 1970s, the risk

was 1 in 11.15 The increase in risk is due to longer life expectancy as well as increases in breast

cancer incidence due in part to changes in reproductive patterns, menopausal hormone use, the

rising prevalence of obesity, and increased detection through screening. Excluding cancers of

the skin, breast cancer is the most common cancer among U.S. women, accounting for 29% of

new diagnosed cancers.15 Breast interventions are used to diagnose and treat many forms of

breast disease and breast cancer and these have improved the quality of life for many female

patients.

Osteoporosis is a chronic disease with late clinical consequences. It has been termed

the “silent epidemic” because there are no associated symptoms or warning signs prior to

fracture. Worldwide, osteoporosis causes more than 8.9 million fractures annually, resulting in

an osteoporotic fracture every 3 seconds.16 In women over 45 years of age, osteoporosis

accounts for more days spent in hospital than many other diseases, including diabetes,

myocardial infarction, and breast cancer.16 Interventional radiology procedures such as

vertebroplasty and kyphoplasty are frequently used to provide symptomatic relief to patients

with vertebral compression fracture due to osteoporosis, a condition known to affect more

women than men.16

An IOM committee defined women’s health broadly, encompassing health conditions

that are specific to women; are more common or more serious in women; have distinct causes

or manifestations in women; have different outcomes or treatments in women; or have high

morbidity or mortality in women.7 In the medical imaging arena, increased public and

professional awareness of the side effects requires imaging personnel to be acutely aware of

the unique risks that the female patient may experience due to exposure to ionizing radiation.

Radiographers are required to be constantly aware of this vulnerability and to recognize steps

that must be taken to make sure that the exposure is as low as reasonable achievable (ALARA).

Such steps depend on the imaging examination being performed, the age of the patient, and the

clinical situation.

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Decision Support

Many physicians order imaging examinations that may or may not yield the desired

diagnostic information. Also, many referrers may not be knowledgeable about alternative

examinations and the radiation dose delivered by various procedures. To help physicians in

determining which imaging examinations will yield the desired information with the least amount

of radiation exposure, the American College of Radiology (ACR) has created image

appropriateness criteria. These guidelines are often considered decision support tools and are

not intended to be inflexible rules or requirements. The ACR Appropriateness Criteria® are

evidence-based guidelines to assist referring physicians and other providers in making the most

appropriate imaging or treatment decision for a specific clinical condition.17 In the criteria, each

treatment and procedure receives a rating on a scale of from 1-9, with 1,2, and 3 noted as

usually not appropriate; 4,5, and 6 receiving a designation that it may be appropriate; 7,8, and 9

being usually appropriate.17 The criteria guidelines specific to the female patient may be found

under the broad categories of breast imaging and women’s imaging criteria. The full list of the

clinical female conditions with variants is available at www.acr.org. For example, the clinical

condition of uterine leiomyoma, previously discussed, is one of the clinical conditions within the

ACR Appropriateness Criteria®. In the radiologic management of uterine leiomyoma, 6 different

variant patient situations are listed. Figure 5 illustrates variant 1.18

Clinical Condition Radiologic Management of Uterine Leiomyoma

Variant 1 45-year old woman with multiple uterine fibroids resulting in a 20-week

sized uterus on physical examination and menorrhagia. The patient has

a recent negative serum pregnancy test and has no desire for future

fertility.

Treatment/Procedure Rating Comments

Hysterectomy 8 Based on patient preference

Uterine artery embolization 8 Based on patient preference

Hormonal therapy 3 May be useful as a temporizing therapy in some instances

Myomectomy 3

MR-guided high-frequency focused ultrasound ablation

2

Endometrial ablation 2 Controls bleeding, but patient remains at risk for bulk-related symptoms eventually

12

Laparoscopic uterine artery occlusion

1

Fig. 5. Adapted from the American College of Radiology. ACR Appropriateness Criteria®. Clinical condition radiologic management of uterine leiomyomas. www.acr.org on November 14, 2013.

18

By employing ACR appropriateness guidelines, physicians and other referring healthcare

providers are able to enhance quality of care and contribute to the most efficacious use of

ionizing radiation.

Frequently Asked Questions about Pregnancy and Radiation Safety

Pregnancy and radiation safety will be discussed later in this course, but the following

provides additional information from the International Atomic Energy Association (IAEA). The

AIEA has developed answers to the most frequently asked questions about pregnancy and

radiation safety.19

1. Is there a safe level of radiation exposure for a patient during pregnancy?

Dose limits do not apply for radiation exposure of patients, since the decision to use

radiation is justified depending upon the individual patient situation. When it has been

decided that a medical procedure is justified, the procedure should be optimized in a

manner that delivers the lowest radiation dose possible.

2. What is the ten-day rule and what is its status?

The ten day rule was developed by the International Council on Radiation Protection

(ICRP) for women of reproductive age. It states that whenever possible, one should

confine the radiological examination of the lower abdomen and pelvis to the 10-day

interval following the onset of menstruation. The original proposal was for 14 days, but

this was reduced to 10 days to account for the variability of the human menstrual cycle.

In most situations, there is growing evidence that a strict adherence to the ten-day rule

may be unnecessarily restrictive. When the number of cells in the conceptus is small

and their nature is not yet specialized, the effect of damage to these cells is most likely

to take the form of failure to implant, or of an undetectable death of the conceptus;

malformations are unlikely or very rare. Since organogenesis starts 3 to 5 weeks post-

conception, it was felt that radiation exposure in early pregnancy could not result in

malformation. The main risk is that of abortion if the radiation exposure results in death

of the conceptus. Fetal death requires a radiation dose of more than 100 milli-grays.

Based on this, it was suggested to do away with the 10-day rule and replace it with a 28-

13

day rule. This means that a radiological examination, if so justified, can be conducted

throughout the cycle until a period is missed. Thus the focus is shifted to a missed

period and the possibility of pregnancy. If there is a missed period, a female should be

considered pregnant unless proved otherwise. In such a situation, the physician and

radiologist should explore alternative non-ionizing radiation examinations for obtaining

the desired information.

3. What if a patient underwent an abdomen computed tomography (CT) before

realizing that she is pregnant?

Occasionally, a patient will not be aware of a pregnancy at the time of an ionizing

radiation examination, and will naturally be very concerned when the pregnancy

becomes known. In such cases, the radiation dose to the conceptus should be

estimated, but only by a medical physicist or radiation safety specialist experienced in

dosimetry. The patient can then be better advised as to the potential risks involved. In

many cases there is little risk, as the irradiation will have occurred in the first 3 weeks

following conception. In a few cases the conceptus will be older and the dose involved

may be considerable. It is however, extremely rare for the dose to be high enough to

warrant advising the patient to consider terminating the pregnancy. If a calculation of

radiation dose is required in order to advise the patient, the radiologic factors should be

known. Some assumptions may be made in the dosimetry, but it is best to use actual

data. The patent’s date of conception or date of last menstrual period (LMP) should also

be determined.

4. Can cardiac catheterization be performed on a pregnant patient?

Yes, there will be many situations where the benefit of performing the procedure is much

greater than any small possible harm that might arise from the radiation exposure.

However, as always with any medical exposure, each particular procedure must be

clinically justified, including in this situation taking into account when the procedure

needs to occur and the anticipated radiation dose to the fetus. Once justified, due care

is taken to optimize how the procedure is performed so as to minimize radiation

exposure to the fetus, consistent with achieving the desired clinical outcome. The

radiation exposure to the fetus predominantly arises from scattered radiation with the

patient. Some of the main methods for minimizing the dose to the fetus include:

restricting the x-ray beam size to being as small as is necessary for the clinical purpose;

14

choosing the direction of the primary beam so that it is as far away from the fetus as

possible; selecting appropriate exposure factors; and ensuring that the overall exposure

time is as small as possible. For optimized imaging procedures, estimated fetal doses

are typically quite small, and well below the level of concern for radiation effects, but

calculations of dose by a knowledgeable medical physicist are desirable.

5. Why have there been decisions on termination of pregnancy after radiation

exposure?

According to the ICRP 84, termination of pregnancy at fetal doses of less than 100 mGy

is not justified based upon radiation risk. At fetal doses between 100 and 500 mGy, the

decision should be based upon the individual circumstances. The issue of pregnancy

termination is undoubtedly managed differently around the world. It is complicated by

individual ethical, moral, and religious beliefs as well as perhaps being subject to laws or

regulations at a local or national level. This complicated issue involves much more than

radiation protection considerations and requires the provision of counseling for the

patient and her partner. At fetal doses in excess of 500 mGy, there can be significant

fetal damage, the magnitude and type of which is a function of dose and stage of

pregnancy. For additional information, consult ICRP 84 (http://www.icrp.org).

6. Can the patient become sterile after undergoing a diagnostic x-ray examination?

The gonads are radiosensitive organs in the human body. The threshold for permanent

sterility in men is 3500-6000 mGy, and for women 2500-6000 mGy. As diagnostic x-ray

examinations involve small doses, they imply no risk of sterility.

Call for Action for Increased Radiation Safety

The International Atomic Energy Association (IAEA) held the International Conference

on Radiation Protection in Medicine: “Setting the Scene for the Next Decade” in Bonn, Germany

in December 2012, with the specific purpose of identifying and addressing issues arising in

radiation protection in medicine.20 An important outcome of the conference was the

identification of responsibilities and a proposal for priorities for stakeholders regarding radiation

protection in medicine for the next decade. This specific outcome is called the Bonn Call-for-

Action. The aims of the Bonn Call-for-Action are to a) strengthen the radiation protection of

patients and health workers overall; b) attain the highest benefit with the least possible risk to all

patients by the safe and appropriate use of ionizing radiation in medicine; c) aid the full

15

integration of radiation protection into healthcare systems; d) help improve the benefit/risk

dialogue with patients and the public; and, e) enhance the safety and quality of radiological

procedures in medicine.20

Additional Course Reading References

The course reading references included with this course are RadioGraphics 2012 article

(Medical Imaging Radiation Safety for the Female Patient: Rationale and Implementation by T.

Rob Goodman, MB Chir, Maxwell Amurao) and the American College of Radiology (ACR) and

the Society for Pediatric Radiology (SPR) guideline (ACR-SPR Practice Guideline for Imaging

Pregnant or Potentially Pregnant Adolescents and Women with Ionizing Radiation revised

2013).These articles are used with copyright permission from the Radiological Society of North

America (RSNA) and the American College of Radiology (ACR) and are used as the reading

references for this continuing education course.

16

Citations

Radiation Safety for the Female Patient

1 Brittle C, Bird CE. Literature review on effective sex-and gender-based systems/models of care. Produced for the

Office on Women’s Health within the U.S. Department of Health and Human Services. Retrieved from http://www.4women.gov/owh/multidisciplinary/reports/Gender-basedMedicine/FinalOWHReport.pdf on August 1, 2013. 2 Key findings from the Kaiser women’s health survey. Retrieved from http://kaiserfamily foundation.files.wordpress.com/2013/01-women-and-health-care-a-national-profile-key-findings-from the kaiser-women-health-survey-report-highlights.pdf. on September 19, 2013. 3 Institute of Medicine of the National Academies. Report Brief September 2010. Women’s health research:

progress, pitfalls, and promise. Retrieved from http://www.iom.edu/~/media/files/report1/120files-progress-pitfalls-

and-promise on September 15, 2013.

4 Gener-related differences in health. Kim JK, Alley D, Seeman T, Karlamangla A, Crimmins E. Recent changes in cardiovascular risk factors among women and men. J Women’s Health (Larchmt) 2006;15:734-746.

5. Kaiser Family Foundation. Executive Summary. Putting women’s health care disparities on the map. Retrieved

from http://kaiserfamilyfoundation.files.wordpress.com/2013/01/7885es.pdf on November 14, 2013.

6. National Cancer Institute. Center to Reduce Cancer Health Disparities. Health disparities defined. Retrieved from

http://chchd.cancer.gov on February 11, 2011.

7. Office of Management and Budget. Standards for the classification of federal data on race and ethnicity.

Retrieved from www.whitehouse.gov on March 14, 2011.

8.National Cancer Institute. Center to reduce cancer health disparities. Retrieved from http:cdchd.cancer.gov on February 21, 2011. 9. Breast Cancer Resource Directory. Multicultural issues and resources: African American women. Retrieved from

http://bcresourcedirectory.org on February 13, 2011.

10. Henry J. Kaiser Foundation. Issue briefs: an update on women’s health policy. March 2004. Retrieved from http:hjk.org on February 4, 2011. 11. Deshmukh SP, Gonsalves CF, Guglielmo FF, Mitchell DG. Role of MR imaging of uterine leiomyomas before and after embolization. RadioGraphics 2012.;32:E251-E281.

12. Katz M D, Sugay S B, Walker D K, Palmer S L, Marx M V. Beyond hemostasis: spectrum of gynecologic and obstetric indications for transcatheter embolization. RadioGraphics 2012.;32:1713-1731. 13. Baron K T, Babagbemi K T, Arleo E K, Asrani A V, Troiano R N. Emergent complications of assisted reproduction: expecting the unexpected. RadioGraphics 2013.;33(1):229-244.

14. Guelfguat M, Gruenberg T R, DiPoce J, Hochsztein J G, Imaging of mechanical tubal occlusion devices and potential complications. RadioGraphics 2012;32:1659-1673. 15.American Cancer Society. Breast cancer facts & figures 2013-2014. Retrieved from

http://www.cancer.org/acs/groups/content/@research/documents/document/acspc-040951.pdf on November 14,

2013. 16. International Society of Bone Health. Osteoporosis statistics. Retrieved from http:www.iofbonehealth.org on November 15, 2013. 17. American College of Radiology. About the ACR appropriateness criteria. Retrieved from

http://www.acr.org/Quality-Safety/Appropriateness-Criteria/About-ACR retrieved on November 11, 2013.

18. American College of Radiology. ACR appropriateness criteria. Radiologic management of uterine leiomyomas.

Retrieved from www.acr.org on November 15, 2013.

19.International Atomic Energy Association. Radiation protection of patients. Pregnancy and radiation protection in

diagnostic radiology. Retrieved from https://rpop.iaea/RPOP/RpoP/Content/SpecialGroups/1_Pregnant women/pregnancyandradiation protectionindiagnosticradiology. On November 14, 2013. 20.Bonn Call-for-Action. Joint position statement by the IAEA and WHO. Retrieved from

https://rpop.iaea.org/rpop/rpop/content/documents/whitepapers/conference/bonn-call-for-actionstatement.pdf on

November 13, 2013.

Note: This copy is for your personal non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights.

1829GENERAL IMAGING ISSUES

T. Rob Goodman, MB, BChir • Maxwell Amurao, PhD, MBA

For the modern practitioner of women’s imaging, achieving a balance between the positive diagnostic benefits available from current medi-cal imaging on the one hand, and the potentially deleterious effects of ionizing radiation exposure on the other, has become a central is-sue. Increased public and professional awareness of the side effects of radiation now require a comprehensive understanding of the facts involved, the various risks to which patients are exposed, and the measures that can be implemented to minimize these risks. The major challenges posed by pregnancy, radiosensitive breast tissue, lactation, and an inability to easily exclude ovaries from the imaging field make female patients particularly vulnerable to medical imaging radiation exposure. The nature of this vulnerability changes frequently and de-pends on the imaging being performed, the age of the patient, and the clinical situation. For this reason, attention to gynecologic imaging ra-diation exposure across the whole life span is vitally important.

IntroductionThe side effects of medical imaging radiation exposure became a formidable problem for radiologists soon after Roentgen discovered x-rays and their deleterious effects first became apparent. There is little doubt, however, that the benefits of using ionizing radiation in medical imaging have considerably improved modern medical practice, and the radiology profession should be proud of the way it has continued to refine and develop this tool in a myriad of different ways to provide even more rapid and accurate diagnoses and treatment options in the gynecology arena. Computed radiography, digital radiography, fluoroscopy, computed tomography (CT), nuclear medicine, and imaging-guided therapy have progressed at an impressively rapid pace, with untold benefits to women’s healthcare. However, any medical imaging that involves ionizing radiation still has inherent drawbacks and side effects, and patients, physicians, the media, and the general public all need to be aware of these potential problems.

Medical Imaging Radiation Safety for the Female Patient: Rationale and Implementation1

Abbreviations: ACR = American College of Radiology, BRE = background radiation equivalent, CTDIvol = volume CT dose index, DLP = dose-length product, PACS = picture archiving and communication system

RadioGraphics 2012; 32:1829–1837 • Published online 10.1148/rg.326125508 • Content Codes: 1From the Department of Diagnostic Radiology, Yale University School of Medicine, 333 Cedar St, PO Box 208042, New Haven, CT 06520 (T.R.G.); and Radiation Safety Department, Georgetown University Hospital, Washington DC (M.A.). Received February 22, 2012; revision re-quested March 28 and received June 15; accepted June 22. M.A. has disclosed a financial relationship (see p 1836); the other author, the editor, and reviewers have no financial relationships to disclose. Address correspondence to T.R.G. (e-mail: rob.goodman@yale.edu).

©RSNA, 2012 • radiographics.rsna.org

1830 October Special Issue 2012 radiographics.rsna.org

Women are particularly vulnerable to ionizing radiation. In childhood, females are more suscep-tible to radiation than males, largely due to su-perficial and dormant breast tissue. In the repro-ductive years, concerns are focused on preventing the inadvertent irradiation of a fetus as well as managing radiation exposure in the context of a declared pregnancy. During lactation, special procedures need to be followed in the context of some nuclear medicine examinations. It is impor-tant, therefore, that radiologists understand the background of and rationale for these concerns and are cognizant of why they have become so important in the imaging of female patients.

In this article, we discuss medical imaging radiation exposure in terms of risks and various mechanisms that can be implemented to minimize these risks, with emphasis on the female patient.

Radiation: Description and SourcesRadiation can take several different forms and is simply a mechanism whereby energy is transmit-ted through space. Medical imaging modalities that involve ionizing radiation make use of elec-tromagnetic waves located near one end of the electromagnetic spectrum. This spectrum con-sists of differing electromagnetic waves that are defined by their electromagnetic wavelength. At one end of the spectrum are the long-wavelength and relatively innocuous radio- and microwaves. As the electromagnetic wavelength decreases, radiation passes through the spectrum of visible light, after which the short-wavelength, high-energy x-rays, gamma rays, and cosmic rays are encountered. This energy has the capacity to be harmful to biologic tissue because it carries the potential to displace electrons from its energy level or shell around the nucleus. This can lead to ionization of the affected atom and explains why these forms of electromagnetic waves are termed “ionizing radiation.” The effects of ion-izing radiation on biologic tissues at the atomic and molecular level are concerning for several reasons. First, a displaced electron can cause damage to other cell components as it is ejected rapidly from its orbit. Second, the resulting highly chemically reactive ionized atom, or “free radical,” can have deleterious effects on the cell of which it is a part. Third, the altered structure of the atom that occurs once an electron is lost may affect the function of the tissue involved (1); this result may be particularly grievous if the involved tissue is a chromosome within a radiosensitive cell such as those found in the

breast or ovary. Because ionizing radiation can cause these associated effects within a patient, it is best to make sure that any ionizing radiation exposure from imaging is appropriately justified and that the benefits far outweigh the associ-ated risks. It is also important to understand the origins of ionizing radiation and the various sources of human exposure.

Humans are exposed to unavoidable forms of ionizing radiation each day. This type of radiation is classified as background radiation and is an unavoidable consequence of living. Background radiation originates from radon gas seeping out of the earth, natural radioactivity being emit-ted from rocks and other organic compounds in the ground, and cosmic rays that constantly rain down from space, among other sources. The level of background radiation varies consider-ably across the globe; a “standard person” in the United States is exposed to an average of approxi-mately 3.1 mSv per year (2), whereas persons in Kerala, India can be exposed to up to 70 mSv per year due to the naturally occurring thorium-coated monazite sand that is found there (3). As recently as 2005, background radiation was understood to be the major source of radiation exposure to the U.S. population, with man-made radiation sources (which include medical imag-ing) accounting for only a small proportion of overall radiation exposure. However, recent data have shown that man-made radiation sources now contribute almost the same amount of exposure to the U.S. population each year as background radiation (Fig 1) (4). Although man-made radia-tion sources include airport security scanners, smoke detectors, television sets, and fluorescent lamp starters, medical imaging accounts for 95% of all exposure from man-made radiation sources (5). The reason for this rapid alteration in the pro-portions of exposure from man-made radiation sources over the past few years has been the phe-nomenal increase in the use of ionizing radiation in medical imaging: In the United States, medical imaging radiation exposure rose from 0.54 mSv per person in 1980 to 3.0 mSv per person in 2006 (2), nearly a sixfold rise.

Medical Imaging Radiation RisksGiven that the majority of radiation exposure is now from man-made sources and that the major-ity of this exposure originates from medical im-aging, it is important to understand the possible effects and risks of this radiation exposure for the human body. Radiation effects can be divided into two general types: deterministic effects and stochastic effects (Table 1).

RG  •  Volume 32  Number 6  Goodman and Amurao  1831

Figure 1. Chart shows the sources of radiation expo-sure in the United States in 2006.

Deterministic effects are the result of the ex-cessive cell death that can occur following ion-izing radiation exposures. These effects include skin erythema, epilation, necrosis, and lens cataract formation. Because these effects occur only after a critical mass of cells have died, they have a known radiation exposure threshold below which their occurrence can be avoided. Once these adverse effects were determined, it paved the way for a radiation protection agenda with the creation of the International Commission of Radiological Protection in 1928 (6). Inadvertent deterministic effects have recently been reported in women following interventional procedures (7,8) and even following CT (9), with radiation burns, hair loss, and skin necrosis being graphi-cally illustrated. These examples serve as a good reminder of the potentially detrimental radiation doses that some of today’s medical imaging de-vices can relatively easily impart.

Stochastic radiation effects are understood to have no threshold level below which they do not occur. Unlike with deterministic effects, the severity of stochastic effects does not increase

with dose, but the likelihood of an effect taking place does increase. Stochastic effects include carcinogenesis and hereditary effects. The possi-bility of a stochastic effect taking place supports the practice of exposures being kept as low as reasonably achievable (ALARA).

Anecdotal evidence from the past showed that patients undergoing radiation treatment for benign conditions such as thymic hypertrophy, tinea capi-tis, or adenoidal enlargement had a propensity to develop tumors in the exposed areas. Later studies showed that girls exposed to x-rays from multiple screening chest radiographs for tuberculosis or ra-diographs for scoliosis were more prone to develop breast cancer than were girls who had undergone no imaging (10). In patients who underwent radi-ography for scoliosis, after a follow-up of 47 years, mortality from breast cancer was 8% higher in the imaged cohort (11). These studies add credence to the current understanding of cumulative radiation exposures, according to which excess cancer risk is increased in females and in children of either gen-der who are exposed at a young age (12). How-ever, even more convincing evidence that medical imaging radiation exposure can cause cancer is based on data generated by the Radiation Effects Research Foundation. This collaboration between the American and Japanese governments has stud-ied a large cohort (n = 90,000) of survivors of the Hiroshima and Nagasaki atomic bomb drops since 1950. These individuals were exposed to varying degrees of radiation and have been studied for the development of cancer over the past 65 years. Data on cancer occurrence in these individuals have been compared with data in controls, and the results to date show that there is a small but direct, statistically significant increased relative risk for cancer mortality following relatively low-dose exposures (5–125 mSv) (13). On the basis of data from this and other studies, it has been proposed that the excess relative risk of cancer mortality from imaging studies exposing women to 10 mSv of radiation is approximately one in 2000 (14). This risk varies depending on certain parameters, but women have been shown to be more sensitive than men (12) and girls twice as sensitive to radi-ation-induced cancers as boys (15). However, it is also important to consider other aspects of risk in a patient’s medical course. Although the risk from ionizing radiation exposure should always be considered, it must be weighed against the risks inherent in not promptly diagnosing or correctly treating the patient’s condition. For example, the risks to the patient and fetus from a potential

Table 1 Types of Radiation Effects

Type Effects

Deterministic Erythema, epilation, skin necrosis, cataract formation

Stochastic Carcinogenesis, hereditary effects

1832 October Special Issue 2012 radiographics.rsna.org

maternal pulmonary embolus far outweigh those from radiation imparted by CT pulmonary angi-ography (16).

Medical Imaging DosesIt is important to understand the various units used to measure radiation exposure. These units relate to different ways of describing ionizing radiation exposure and include absorbed dose (measured in grays [Gy] or rad) and effective dose (measured in sieverts [Sv] or rem). Ab-sorbed dose is simply a measurement of the total amount of radiation energy absorbed per volume of tissue exposed. As such, absorbed dose pro-vides little information on biologic effects, and although it can be used to compare the different amounts of radiation to which the whole body has been exposed from different imaging sources, it bears no relation to the type of tissues involved. Effective dose is a much more relevant measure-ment, given that a weighting factor is applied to the radiation dose; this factor is determined on the basis of the tissue or organs exposed as well as the type of radiation involved. The weighting factor represents the proclivity of a tissue to de-velop stochastic effects, with (for example) breast (0.12) and ovaries (0.08) having a greater weight-ing factor than brain or salivary glands (both 0.01) (17). Thus, identical ionizing radiation ex-posures to the breast and head might have similar absorbed doses, but the breast exposure would have a much higher effective dose, reflecting the increased cancer risk.

The radiologist should have a clear under-standing of the relative dose weightings of vari-ous imaging procedures. It is important to keep in mind that effective dose is an estimate of the radiation effect to a population, not to a specific patient or group. These estimates are based on an idealized standard man and woman. With that said, converting the dose used for a study into a “background radiation equivalent” (BRE) is helpful in counseling patients and educat-ing referring clinicians (Table 2). The average background effective dose in the United States is approximately 3.1 mSv per year. A single frontal chest radiograph has an approximate effective dose of 0.02 mSv and therefore a BRE of 2.3 days. A pelvic radiograph has a higher effective dose (~0.6 mSv, BRE = 71 days) due to the in-volvement of the ovaries and the density of the involved tissue. Modern screening mammogra-

phy has an effective dose of about 0.4 mSv (BRE = 47 days), but a barium enema study has a much higher effective dose of 8 mSv (BRE = 2.6 years). However, the highest gynecologic study doses originate from CT scans and fluoroscopic in-terventional procedures. CT of the chest, abdo-men, and pelvis can result in an effective dose of approximately 21 mSv (BRE = 6.7 years), and an interventional study such as uterine-pelvic vein embolization can have an effective dose of roughly 60 mSv (BRE = 19.3 years) (18).

Although interventional radiologic procedures can impart a considerable radiation exposure, CT is a greater source of radiation to the female population as a whole. The number of CT stud-ies performed has increased considerably over the past 20 years, in part because of its accessibility, the increased number of clinical indications, and its speed of acquisition. In 2006, CT accounted for nearly one-half of all radiation exposure to the U.S. population from medical imaging, despite accounting for only 17% of all imaging proce-dures (Table 3) (2).

Age, pregnancy, and lactation status also play important roles in determining a patient’s radia-tion risk from gynecologic imaging. The excess relative risk of carcinogenesis from radiation is nearly three times higher in children under the age of 10 years than in the population as a whole (19). This can be explained by (a) the growing child’s high rate of mitosis; (b) his or her longer life expectancy, during which a radiation-induced malignancy may develop; and (c) the difficulty in limiting exposures to nonradiosensitive areas due to his or her small size. The gravid uterus is

Table 2 BREs for Various Gynecologic Imaging Studies

Study Dose (mSv) BRE

Frontal chest radiography 0.02 2.3 dMammography 0.4 47 dPelvic radiography 0.6 71 dBone scintigraphy 6.3 2 yBarium enema study 8 2.6 yFDG PET scintigraphy 14.1 4.5 yChest/abdominopelvic CT 21 6.7 yUterine-pelvic vein

embolization60 19.3 y

Note.―FDG = 2-[fluorine-18]fluoro-2-deoxy-d-glucose, PET = positron emission tomography.

RG  •  Volume 32  Number 6  Goodman and Amurao  1833

also a radiosensitive organ owing to the develop-ing fetus, and theoretic effects from radiation (based on animal and human studies) include prenatal death, growth retardation, mental re-tardation, and childhood cancer (20). However, doses under 50 mGy (10 mSv) have not been associated with an increase in fetal anomalies or pregnancy loss (21), which is reassuring given that an estimated dose to the conceptus (ie, em-bryo or fetus) from abdominopelvic CT is ap-proximately one-half this amount (20). Although animal studies have demonstrated no increased radiation risk to the lactating breast vis-à-vis the nonlactating breast (22), lactation status has important implications for nuclear medicine, in which inadvertent exposure of the nursing child to radioisotopes should be avoided. Maternal radiopharmaceuticals can be excreted in breast milk and, if ingested by the child, may accumu-late within the child’s organs. For example, it has been calculated that imaging with sodium iodide iodine-131 can deliver an effective dose of 5400 mSv/MBq to the neonatal thyroid gland (23). As a result, temporary or permanent cessation of breast-feeding following the administration of certain radiopharmaceuticals is suggested (23).

The breast is an organ that deserves particu-lar mention in the context of radiation exposure because of its radiosensitivity, high incidence of inherent malignancy, and superficial location on the chest wall. The breast is frequently exposed to ionizing radiation during chest imaging, one of the most commonly performed imaging stud-ies. For example, in the workup of a patient with a suspected pulmonary embolus, the dose to the breast from CT pulmonary angiography is higher than that from a ventilation-perfusion scan (16). However, CT pulmonary angiogra-phy is the most commonly used imaging tool for

detecting pulmonary emboli―and patients are often young, female, or both. In one study, 60% of CT pulmonary angiographic examinations were performed in women, 25% of whom were under 40 years of age (24).

Dose Reduction ImplementationDose reduction initiatives in gynecologic imag-ing can be divided into (a) examination-specific strategies and (b) general strategies.

Examination-specific Strategies

Computed-Digital Radiography.―Relatively simple techniques and protocols in computed-digital radiography practice can reduce the dose burden to female patients. For example, having the patient empty the bladder before undergoing radiography of the lumbar spine can reduce the dose to the ovaries by over 40%, since the ova-ries are more likely to have moved outside the field of view (25). The concept of appropriate and effective gonadal shielding is also impor-tant to consider when imaging a young female patient; it fosters reassurance and comfort to the parent or caregiver and reduces radiation exposure to the patient. However, studies have shown that these shields are often inaccurately placed and provide little or no protection to the ovaries. In one study of radiographs obtained in several thousand girls, gonadal shields were ac-curately placed in just over one-quarter of cases (26). Responsible radiology departments can easily review the correct location of the ovaries and the best way to protect them with appropri-ate shielding (Fig 2) (27), as well as supervise maneuvers such as bladder emptying.

Table 3 Medical Radiation Exposure to the U.S. Population in 2006

ProcedureNo. of Proce- dures (×106)*

Collective Dose (person-Sv)*

Dose Per Capita (mSv)

Radiography 281 (73) 96,000 (11) 0.3Interventional procedures 17 (4) 129,000 (14) 0.4CT 67 (17) 440,000 (49) 1.5Nuclear medicine 19 (5) 231,000 (26) 0.8 Total 384 (100) ~900,000 (100) ~3.0

Source.—Reference 2. *Numbers in parentheses indicate (rounded) percentages.

1834 October Special Issue 2012 radiographics.rsna.org

Figure 2. Anteroposterior pelvic radiographs show correct (a) and incorrect (b) positioning for female gonadal shields. Note that correct positioning obscures a significant amount of the pelvis and would not be ap-propriate in many clinical situations (eg, trauma).

Fluoroscopy.―Dose exposure reduction in fluo-roscopic procedures requires attention to detail and a vigilant approach to protocols. Although some aspects of traditional hysterosalpingography have been replaced by sonohysterography and pelvic magnetic resonance imaging, conventional fluoroscopic hysterosalpingography may still be required. A conventional hysterosalpingographic examination has the most stringent dose reduc-tion requirements, since patients are usually young and attempting pregnancy; yet, by defi-nition, evaluation of the involved area requires exposure to the uterus and ovaries. Pregnancy testing prior to the examination is a manda-tory component of the study protocol, although studies performed inadvertently on pregnant patients have been described (28). Studies have also shown that the radiation dose from hys-terosalpingography has fallen as the number of required exposures and views has been reduced. Although dose reduction can also be achieved with modern technologic advances in the form of pulsed and digital fluoroscopy, factors such as limiting magnification and reducing the im-age receptor–to-skin distance can also be used (29). Other basic approaches to fluoroscopy that can easily be implemented to reduce radiation exposure include setting an audible alarm to go off after the passage of a certain amount of study time, removing the grid for the imaging of small patients, reducing ambient lighting to maximize screen visibility, and avoiding radiosensitive areas whenever possible. Educational materials such as the “Step Lightly” campaign from the Society for Pediatric Radiology (30) are an ideal resource for identifying and reinforcing these techniques.

Computed Tomography.―The main practical steps to reducing radiation exposure from CT in-clude modifying the parameters for milliampere-seconds and kilovolt peak in imaging protocols and, in certain situations, considering the use of bismuth latex breast shields.

The CT tube current, or milliamperage, is directly proportional to the dose received by the patient, and keeping this operator-dependent parameter as low as possible is vital for successful dose reduction. However, a milliamperage that is too low will result in increased noise; thus, a bal-ance needs to be struck between use of the lowest possible dose and preservation of image quality. Most modern scanners make use of automatic exposure control or tube current modulation (31), features that automatically reduce the tube current as the radiation beam passes through less

dense or less thick tissue. Attenuation is calcu-lated from the scout image, and the milliamper-age is adjusted accordingly depending on the body part being examined or the type of study. Given that the scout image determines the at-tenuation, it is vital that the patient is centered in the gantry appropriately, since differences in table height can alter the attenuation calculations (32). The image should be optimized for the study type, rather than simply for the body part being imaged. For example, diagnostic abdominal CT performed in a patient with an ovarian carcinoma would require a higher milliamperage than would abdominal CT for renal calculi.

Attention to the peak tube potential, or kilo-volt peak, can also be helpful in image dose re-duction. Although a low kilovolt peak results in a reduced dose and increased noise, it also has the benefit of increased contrast resolution (33). This occurs in part because the mean photon energy

RG  •  Volume 32  Number 6  Goodman and Amurao  1835

at 80 kVp is closer to the k edge of iodine (32 keV) than at higher kilovolt peak settings. This may be of particular importance in contrast ma-terial–enhanced studies (in which the conspicu-ity of enhancing structures is maximized) and in studies aimed at stone detection.

The increased noise encountered at low–kilo-volt peak scanning is also less manifest in small patients (such as young girls); thus, kilovolt peak settings need to balance the increased noise and contrast resolution against patient size and the purpose for the study. Taking these factors into account means that high-quality, dose-responsi-ble CT protocols can be created.

Bismuth latex shields can be placed over tis-sues that are superficial but radiosensitive, such as the thyroid gland, lens, or breast tissue (de-veloped or dormant). These shields generate minimal image distortion and can result in dose reductions to the anterior surface of the breast of up to 40% (34). Although the use of shields provides reassurance and a feeling of protection to the patient, a concerted effort at reducing tube current has been shown to provide similar dose reduction results with no image distortion (35).

General StrategiesIonizing radiation has been classified as a carcin-ogen by the World Health Organization (36) and many other health-related agencies, and is there-fore in the same category as asbestos and ben-zene, substances in which considerable effort and costs are expended in dealing with compensation, litigation, and exposure prevention. It is unlikely that ionizing radiation (and medical imaging ion-izing radiation in particular) will escape this type of scrutiny in the foreseeable future given its car-cinogenic status. Indeed, the Joint Commission recently issued a sentinel alert on this topic (37). We may expect additional legislation governing ionizing radiation exposure from medical imaging to be enacted in the near future because, apart from mammography, there is to date no federal legislation in the United States regulating the use of medical imaging ionization radiation exposure devices (38).

JustificationEurope has a much lower medical imaging radia-tion exposure level per capita than the United States (2). This may be due in part to the Eu-ropean Commission Directive (39), which has empowered member countries to enact legisla-tion such as the United Kingdom’s Ionising Radiation (Medical Exposure) Regulations (40). These regulations legally empower radiologists to justify each exposure before it takes place and

consequently provide fertile ground for referrer education and appropriateness awareness. How-ever, educating referrers by means of radiologist justification can be time consuming and some-times combative. An alternative mechanism that is likely to improve request justification with a minimum of clinical disruption is the concept of decision support. The American College of Radi-ology (ACR) has created image appropriateness criteria (41) that determine the appropriateness (and relative radiation value) of an investigation on the basis of the indications and clinical de-tails provided by the requestor. In this way, the most clinically relevant and radiation-appropriate study can be identified. This has been shown to be particularly effective in reducing exposure to ionizing radiation from medical imaging when linked electronically to a computerized physician order entry system (42). For example, when a clinician orders CT for suspected ovarian torsion, the program would suggest to the clinician that ultrasonography is the more appropriate exami-nation, and the clinician can order that examina-tion instead. The physician has the ability to over-ride this suggestion; to date, however, users have demonstrated an increase in diagnostic yield and reduction in exposure with such programs (43).

Dose RegistryKnowing the approximate dose a CT scan im-parts to an individual patient is fundamental to a departmental program for responsible dose reduction. Modern CT scanners generate a dose report, which usually contains information on the study’s volume CT dose index (CTDIvol) and dose-length product (DLP). CTDIvol is a measurement of radiation output imparted by the scanner to an acrylic “typical adult” or “typi-cal pediatric” phantom using the parameters set by the technologist for that examination (44). Therefore, the resulting CTDIvol bears no relation to the body part being imaged or the sex, age, or size of the patient. DLP is simply the product of CTDIvol and scan length (in centimeters). Most institutions now upload these dose reports to a picture archiving and communication system (PACS) (Fig 3) so that radiologists and referrers are able to reference the appropriate radiation metrics. Although DLP is not a representation of dose received by the individual patient per se, a conversion factor for various body parts can be applied to obtain an approximate effective dose (45). This is the mechanism used for ACR CT accreditation criteria and is particularly useful in pediatric imaging (in which differences in dose

1836  October Special Issue 2012 radiographics.rsna.org

Figure 3. Screen shot shows a typical PACS CT dose report.

between adult and pediatric CT technical pro-tocols can be demonstrated) and in patients of any age in whom anomalous imparted doses are identified. A dose report on a PACS makes these cases readily apparent and facilitates investigation and root cause analyses to prevent future occur-rences. Applying this form of dose monitoring on a wider scale is currently being undertaken by the ACR Dose Index Registry program (46). With this program, institutions can subscribe to a ser-vice whereby each CT scan dose report is auto-matically sent to a central repository where local figures are compared with national benchmarks for the test in question. In this way, outlying in-stitutions can easily be identified, their protocols subsequently optimized, and their doses conse-quently reduced.

ConclusionsImplementing reductions in radiation exposure and an awareness of the consequences of such ex-posure at gynecologic imaging can be undertaken at both the local and wider level. This article has explained the rationale for limiting medical imag-ing radiation exposure in female patients and has identified several implementation strategies for dose reduction. Addressing these issues will help encourage the use of safe, appropriate, and high-quality protocols in women’s imaging.

Disclosures of Conflicts of Interest.—M.A.: Related financial activities: none. Other financial activities: course developer for the Radiological Society of North America.

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Teaching Points October Special Issue 2012

Medical Imaging Radiation Safety for the Female Patient: Rationale and ImplementationT. Rob Goodman, MB, BChir • Maxwell Amurao, PhD, MBA

RadioGraphics 2012; 32:1829–1837 • Published online 10.1148/rg.326125508 • Content Codes:

Page 1830In the United States, medical imaging radiation exposure rose from 0.54 mSv per person in 1980 to 3.0 mSv per person in 2006 (2), nearly a sixfold rise.

Page 1831Inadvertent deterministic effects have recently been reported in women following interventional proce-dures (7,8) and even following CT (9), with radiation burns, hair loss, and skin necrosis being graphi-cally illustrated.

Page 1831Data on cancer occurrence in these individuals have been compared with data in controls, and the results to date show that there is a small but direct, statistically significant increased relative risk for cancer mortal-ity following relatively low-dose exposures (5–125 mSv) (13).

Page 1833For example, having the patient empty the bladder before undergoing radiography of the lumbar spine can reduce the dose to the ovaries by over 40%, since the ovaries are more likely to have moved out-side the field of view (25).

Page 1834Although a low kilovolt peak results in a reduced dose and increased noise, it also has the benefit of increased contrast resolution (33).