TUMOR IMAGING MUDr. Kateřina Táborská. 1.Differentiation of benign from malignant lessions...

TUMOR IMAGINGTUMOR IMAGING

MUDr. Kateřina Táborská

1. Differentiation of benign from

malignant lessions

2. Staging of malignant disease

3. Differentiation of reccurent malignant

disease from therapy induced changes

4. Monitoring the response to therapy

Objectives of Tumor Imaging

AGENTS

Choise depends on:

• Mechanism of uptake

• Sensitivity for detection of malignant lesion

• Specificity of uptake

• Sites of normal physiological uptake in the body and routes of excretion

• availability

Radiopharmaceuticals

Nonspecific affinity for neoplastic tissue, may be used to image a range of tumors in various organs

18F Fluorodeoxyglucose

67Gallium citrate

201Thallium

99m Tc sestamibi

Designed to label specific tumor antigens, receptors

111In Octreoscan

123I MIBG

123/131 I NaI

Positron Emission TomographyIs rapidly becoming a major diagnostic modality

similar to conventional NM in principle, but it uses diferent radiopharmaceuticals + more complex acquisitions method – better resolution

based on coincidence detection of two gamma rays (511 keV) that originate from annihilation of positron – electron pair

PET radiopharmaceuticals contain short half-life radionuclides (prepared in cyclotron), that decay, emitting positrons

Radionuclidhalf-life (mins)

RPH metabolic pathway

18F 110 18F-FDGglucose

metabolism

11C 20 11C-methionin protein syntesis

13N 10 13NH3 blood flow

15O 2 15O - H2O blood flow

18FDG tracer of glucose metabolism

Estimate the rate of glucose utiliation

blood cell

x greater number of Glucose transporter proteins

Elevated levels of intracellular enzymes that support glycolysis

x

Tumor cells demonstrate glucose metabolism

Physiological distribution of 18 FDG

brain

myocardium

bowel

liver

spleen

excreted by the kidneys

Inflammation specificity

Examination

1. Patient preparation 6 hours fasting, good hydration2. Check blood glucose level-lower than 8,3 mmol/l3. RP administration – iv.4. Accumuation phase – 60 - 90 minuts5. Whole body scanning 5-7 bed position, emission,

transmission (CT)6. Data processing7. Evaluation

Contraindicaton

pregnancy, hyperglycaemia, inability to lie without movement during acquisition

Oncology

Lung cancerHead and neck cancerColorectal cancerEsophageal cancerLymphomaMelanomaBreast cancerThyroid cancerCervical cancerPancreatic cancerBrain tumor

Differentiation of benign from malignant lessions

SOLITARY PULMONARY NODULE(about a third of SPN in patients older than 35yr malignant)

chest x-ray metabolism of FDG CT sputum cytology + - bronchoscopy mediastinum percutaneous needle biopsy distant metastases mediastinoscopy open lung biopsy

Sensitivity 95%, specificity 80% (CT sensitivity 100%, specificity 50%)


SOLITARY PULMONARY NODULE

- Weight lost (15 kg) - CT and endoultrasound suspicion of malignancy- high risk patient undergoing dialysis- PET negative- clinical follow up without progression


Staging of malignant disease is essential for treatment (surgery, chemotherapy)

Functional changes preceed anatomical

N,M morpologic imaging is less accurate

dependent on the size - 1 cm in thorax, 1-2 cm abdomen

Staging of malignant disease : lung cancer

According to CT

T2N0M0

Dision operation

According to PET

T2N0M1

Dision chemotheraphy

Differentiation of reccurent malignant disease from therapy induced changes

MRI 18FDG

MRI : metastases of lung Ca – frontal region - necrosis? FDG: frontal region ametabolism (necrosis), occipital region hypermetabolism

Differentiation of reccurent malignant disease from therapy induced changes

Hodgkin‘s lymphoma, KS II A(bulky mediastinum, neckrestaging after 2. cycle of chemotherapy

Monitoring the response to therapy

Hodgkin‘s lymphoma

before treatment after treatment

6767Ga citrateGa citrate

lymphomalymphoma

labeled monoclonal antibody (OncoScint, CEA scan)labeled monoclonal antibody (OncoScint, CEA scan)

colorectal, ovarian cancercolorectal, ovarian cancer

99m99mTc MIBI, TETROFOSMIN, DMSA(V)Tc MIBI, TETROFOSMIN, DMSA(V)

thyroid Cathyroid Ca

ALTERNATIVES

thyroid Cathyroid Ca 99mTc MIBI99mTc MIBI

99mTc MIBI – parathyroid adenoma99mTc MIBI – parathyroid adenoma

Dual-phase scanDual-phase scan

Accumulation by thyroid and parathyroid tissue in proportion to blood flow and metabolic rate

Activity in normal parathyroid glands is too low to be seen on image, abnormal uptake > 300 mg

Wash out of normal thyroid tissue is faster than from abnormal parathyroid adenomas and hyperplasia

99mTc MIBI – parathyroid adenoma99mTc MIBI – parathyroid adenoma

Dual-phase scanDual-phase scan

iv.

Early images (10-15 min) delayed images (2 hours)

NEUROENDOCRINE TUMORS

Derived from pluripotent stem cells or differentiated neuroendocrine cells

• capacity to synthesize hormones/ peptide neurotransmitters

• biogenic amine precursor uptake and decarboxylation (APUDomas)

• intracytoplasmic storage granule on electron microscopy

• express cell surface receptors for somatostatin


paragangioma

neuroblastoma

pheochromocytoma (catecholamine)

carcinoid (serotonin and metabolites)

medullary thyroid cancer (calcitonin)


localisation, characterisation

123123II MIBG 111In OCTREOSCAN

therapy

131I MIBG

123I-, 131I- METAJODBENZYLGUANIDIN

123123I I T1/2 13 hours, T1/2 13 hours, γγ rays 27, 159, 529 keV rays 27, 159, 529 keV

131131II T ½ 8,04 days, T ½ 8,04 days, ββ, , γγ rays rays

structurally resembles norepinephrineaccumulation in cytoplasmic catecholamine storage granules

adrenal medulla, sympathetic nervous tissue

tumor cells that posses the type-1 amine uptake mechanism


SENSITIVITY:

Feochromocytoma 80-90 %Carcinoid 50-60 %Paraganglioma 40-60 %MTC 30 %


Preparation:

to minimize thyroid uptake (KI, Lugol‘s solution)

Stop drugs that interfere

with MIBG uptake

(catecholamine agonist)

Imaging:

24 h after iv.

medullary thyroid ca

111In-OCTREOSCAN®

Pentetreotid - somatostatin analog

Somatostatin - neuropeptide (first found in the hypothalamus)

high density of somatostatin receptors

NT, astrocytoma, meningeoma, breast ca, lymphoma

111In T ½ 67h, (γγ rays 171, 245keV)

111In-OCTREOSCAN®

SENZITIVITY:

Glukagonom 100 %Vipom 88 %Gastrinom 73 %Nesekreční GEP 82 %Feochromocytom > 85 %Karcinoid 86 – 96 %MTC 65 – 70 %Malubuněčný Ca plic 80 – 100 % Inzulinom 46 %

www.snm.org, guideline, II/2001

111In-OCTREOSCAN®

Imaging :

4-6h, 24 h after iv.

carcinoid

SENTINEL LYMPH NODE DETECTION

First node in a lymph node bed to which a tumor cell would come if it penetrated into lymphatic fluid

If an sentinel node is tumor free, with 97-98% accuracy, there is no tumor spread to any lymph node


STAGING

PROGNOSIS

breast

prostate

cervix, vulva

melanoma


Radiopharmaceuticals

99mTc albumin colloids (Senti-Scint® 100-600 nm)

EXAMINATION:

on the morning of surgery (1 day before)

aplication

subdermal

intratumoral

peritomoral


EXAMINATION:

Imaging, marked on skin

In the operating room – hand held gamma detecting probe (combination with blue dye)

CONCLUSION

ADVANTAGES functional information

DISADVANTAGES lack of anatomic precise localisation

SOLUTION

SPECT/CT

PET/CT

TUMOR IMAGING MUDr. Kateřina Táborská. 1.Differentiation of benign from malignant lessions...

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