Biology Lesson # 7

Health Care & Medical Imaging

Diagnosing Problems in Organ Systems

• Since organ systems are interdependent, it is sometimes difficult to diagnose and treat medical problems.

• A common physical examine includes:– Looking at your eyes, ears, and skin to

check your surface organs.– Tapping of your chest and abdomen to

determine the size and density of your organs.

– Using a stethoscope to listen to the heart and lungs determine if they are functioning properly.

Testing Circulation

•A pulse and blood pressure check to see if they are within normal ranges

•The average pulse ranges from 60-80 beats/minute.•Blood pressure is a measure of the pressure of blood against the walls of the arteries and is represented by two numbers:

– the first being the systolic pressure - when the heart contracts (and pushes blood out)– the other being the diastolic pressure - when the heart relaxes (and fills with blood). –High blood pressure can cause damage to the arteries, and lead to heart attacks.

Testing Blood & Urine

•Blood is taken to test red and white blood cells counts, sugar and hormone levels (which are chemicals that carry messages to regulate cells, tissues or organs).•Urine is taken to test for kidney function. They check for:

–White blood cells (which may be sign of infection)–Very little urine (kidneys are not working effectively to clean the blood of wastes)–Too much urine (pancreas may not be working properly, or could also be a symptom of a type of diabetes).–Prescription and illegal drugs

Diagnostic Testing–Provides information about the structure and function of organs, tissues, and cells through medical imaging. –Imaging is done by a technician and a radiograph is produced. The test is read and interpreted by a radiologist.–In Canada, medical imaging is included as a part of our health care system for necessary (not elective) procedures, but depending on your location in the country, there are sometimes long wait times for available appointments using these equipment, as they are very expensive to maintain.

1. X-RayHow It Works•An X-ray is high energy radiation that can easily penetrate materials like skin and tissues. Bone and metals absorb the energy instead, which is why they appear whiter than other structures •Pros: Virtually painless, quick, non-invasive, most common form of medical imaging.•Cons: Can cause changes and mutations to DNA, which is why parts of your body not being examined must be covered with a protective lead apron to limit the penetration of X-rays in those areas.

1. X-RayUses•To check for cancer•To diagnose problems in the cardiovascular and respiratory systems•Mammograms radiographs reveal abnormalities in the lungs, shows the size of the heart, and blood vessel structures•Used by dentists to check for cavities

1. X-RayFluorscopy•Fluoroscopy is a subtype that uses a continuous beam of X-rays to produce images that show movement of organs like the stomach, intestine, colon, heart vessels (angiogram), or brain vessels (cerebral angiogram). •A contrast liquid like barium or iodine must be used to see them clearly.

1. X-Ray

Radiation Therapy•X-Rays can cause cancer, but can also be used to treat cancer if targeted at specific cancer cells.•The radiation slows down or stops the multiplying of cells.

1. X-RayComputed Tomography (CT)•Involves using X-ray equipment to form a three-dimensional image from a series of images taken at different angles of the body•Can image bone, tissue and blood all at the same time in detail•Used to diagnose cancer, abnormalities of the skeletal system, and vascular diseases.•Not good for those who are claustrophobic as it is a confined space.

2. UltrasoundHow It Works•Uses high-frequency sound waves, made from a device called a transducer, to produce images of body tissues and organs. •The transducer is placed on the skin, and sound waves enter the body and are reflected back like an echo to the transducer by internal body structures – the reflection makes an image of the body structures, viewed on a screen by a technician•Pro: does not use radiation, quick and painless•Con: cannot be used in areas that contain gas or air (like the intestines or stomach) as they blur the image produced, cannot penetrate bone

2. UltrasoundUses•Study soft tissues and major organs, and can be used to guide needles during biopsy into correct body tissues•In pregnancy to study the developing fetus and to check for abnormalities•Can be used to diagnose heart problems – called an echocardiogram (ECG) – to check heart valves and check for blood clots that could lead to stroke

3. Magnetic Resonance Imaging (MRI)

How It Works•Uses powerful magnets and radio waves to produce detailed images of the body on a specialized computer •The magnet produces a strong magnetic field that interacts with hydrogen. Since our body is mostly water – H2O – this works very well.•Pros: creates a detailed image, painless. Less confining than a CT so better for patients with anxiety or disabilities.•Cons: cannot be used by those who have metal fillings or implants, or who work with metal.

3. Magnetic Resonance Imaging (MRI)

Uses•Many uses including structure and function of the brain, heart, liver, soft tissues, and the inside of bones.•Can diagnose cancer, brain disease, and cardiovascular conditions

4. Nuclear Medicine

How It Works•Uses radioisotopes to provide images of how tissues and organs function.•Radioisotope is a radioactive form of a chemical that emits radiation.Uses•Radioactive iodine is used to treat thyroid cancer – the thyroid absorbs the iodine and kills the cancer, and after a few days the iodine decays to a non-harmful iodine and is excreted by the body.•Also used in the treatment of prostate and breast cancer.

4. Nuclear Medicine

Positron-Emission Tomography (PET)•Is a type of nuclear medicine, but the radioactive chemical chosen emits particles called positrons which can detect cancer.•Commonly to detect cancer in tissues and examine a treatment’s effectiveness.•Also used to detect heart disease, brain disease and disorders like Alzheimer’s and epilepsy.

5. Biophotonics•How It Works

–Uses the interactions of light with cells and tissues to diagnose and treat abnormalities.–When light shines on cells, the particles of light are scattered by atoms in the cells, and an imaging device records the scatter. –Scatters are different for abnormal cells versus healthy cells.

•Uses–Endoscopes are thin flexible tubes with a light attached used to examine the digestive tract – used during endoscopies and colonoscopies.–Very useful during surgery that is deep in the body in small, confined spaces. Often a camera is attached on the end as well so that all staff can observe procedures.

5. Biophotonics•How It Works

–Uses the interactions of light with cells and tissues to diagnose and treat abnormalities.–When light shines on cells, the particles of light are scattered by atoms in the cells, and an imaging device records the scatter. –Scatters are different for abnormal cells versus healthy cells.

•Uses–Endoscopes are thin flexible tubes with a light attached used to examine the digestive tract – used during endoscopies and colonoscopies.–Very useful during surgery that is deep in the body in small, confined spaces. Often a camera is attached on the end as well so that all staff can observe procedures.

Factors Affecting Diagnosis & Treatment

•The doctor ordering the most appropriate test•The patient understanding what the test is for, and preparing for and following directions during the test•The technician administering the test properly•The radiologist properly reading and understanding the image•The administrators allocating adequate funding for technology