Chapter 20 - In Vivo: Tracer Studies

Question 1

Bone scan

Answer 1

A radioactive (technetium-99m) phosphate is injected intravenously and bones are scanned for evidence of infection, inflammation, or tumors

Question 2

Lymphoscintigraphy

Answer 2

1. Provides pictures (scintigrams) of the lymphatic system
2. Diagnostic test that is performed to detect damage or malformations of the lymphatic vessels
3. Identifies sentinel lymph node

Question 3

Positron Emission Tomography (PET) (!!!)

Answer 3

1. Use of radioisotopes (emission of positrons) instead of contrast
   x-rays.
2. Intravenous injection of radionuclide
3. Concentrates radioisotopes in tissues where the radionuclide is or is not being metabolized.
4. Useful for Alzheimers, epilepsy, stroke, brain tumors, abdominal and pulmonary malignancies, and schizophrenia

Question 4

PET-CT scan

Answer 4

1. Combines PET and CT techniques to produce a more accurate image than PET or CT alone
2. Detects cancer and metastases

Question 5

Single photon emission computed tomography (SPECT) (!!!)

Answer 5

1. Involves intravenous injection of radioactive tracer
2. Involves computer reconstruction of a 3D image based on a composite of many views.
3. Detects liver tumors, cardiac ischemia, diseases of bone and spine

Question 6

Technetium Tc99m sestamibi (Cardiolite) scan

Answer 6

A nuclear medicine study in which a radiopharmaceutical sestamibi scan (Tc 99m sestamibi) is injected intravenously and traced to heart muscle to observe heart function.

Question 7

Thallium scan

Answer 7

Thallium 201 is injected intravenously to allow for myocardial perfusion and assess damage to heart muscle from heart attacks (“cold spots”)

Question 8

Thyroid scan

Answer 8

1. Iodine-123 radionuclide is given orally and scan reveals the size, shape, and position of the thyroid gland
2. Radioactive technetium can be used alternatively and given intravenously.
3. “Hot nodule” = adenomas = benign. “Cold nodule” = malignancy.