Nuclear Medicine Notes

NUCLEAR MEDICINE

Introduction

  • Definition: Nuclear Medicine is a medical specialty that uses radioactive substances (radiopharmaceuticals) for diagnosis and therapy.

  • Principles: Based on the detection of gamma rays emitted from the administered radiopharmaceuticals.

Radiopharmaceuticals

  • Definition: Radioactive drugs used in tracer quantities for diagnosis or therapy with no pharmacological effect.

List of Radiopharmaceuticals

  • Carbon-11 (11C)

  • Chemical Form: Carbon-11 Choline

  • Half-life: 20.334 minutes

  • Uses: PET imaging for suspected prostate cancer recurrence.

  • Carbon-14 (14C)

  • Chemical Form: Carbon-14 Urea

  • Half-life: 5,730 years

  • Uses: Aid in diagnosing H. pylori infection.

  • Fluorine-18 (18F)

  • Forms: Florbetapir, Sodium Fluoride, Fludeoxyglucose

  • Half-life: 109.771 minutes

  • Uses: PET imaging for prostate cancer, bone imaging, glucose metabolism in oncology, etc.

  • Gallium-67 (67Ga)

  • Chemical Form: Gallium Citrate

  • Half-life: 3.26 days

  • Uses: Detect Hodgkin’s disease, lymphoma, bronchogenic carcinoma, etc.

  • Indium-111 (111In)

  • Various chemical forms

  • Half-life: 2.80 days

  • Uses: Imaging prostate cancer, labeling monoclonal antibodies, CSF imaging, etc.

  • Iodine-123 (123I)

  • Forms: Iobenguane, Ioflupane, Sodium Iodide

  • Half-life: 13.22 hours

  • Uses: Thyroid function evaluation, neuroendocrine tumor imaging.

  • Technetium-99m (99mTc)

  • Various forms

  • Half-life: 6.0058 hours

  • Uses: Imaging in various organs, bone scans, myocardial perfusion, etc.

Instrumentation and Quality Control

  • Geiger-Mueller Counter: Sensitive, low-cost instrument detecting low levels of radioactivity; limited exposure handling.

  • Ionization Chamber: Measures various exposure rates, specializes in low exposure.

  • Sodium Iodide Well Counter: In vitro study instrument for quantifying radioactivity in samples.

  • Dose Calibrator: Essential for measuring and calibrating dose of isotopes before injection.

  • Gamma Camera: Converts emitted photons into images, key in imaging devices; components include scintillation crystals and photomultiplier tubes.

Clinical Applications

  • Oncology: PET scans help assess tumor metabolism and identify malignancy through increased glycolysis.

  • Cardiology: PET or SPECT imaging for myocardial perfusion; assesses blood flow

  • Gastrointestinal Studies: Various radionuclide studies for diagnosis and evaluation of conditions, e.g. reflux, gastric emptying.

  • Neurology: Imaging for brain function; differentiates between conditions like seizures, dementia, and tumors.

Definition of Terms

  • Radiopharmaceutical: Radioactive substances used for therapeutic or diagnostic procedures.

  • Beta particle: Electrons emitted from the nucleus during decay.

  • Gamma ray: High-energy radiation emitted from radioactive substances.

References

  1. Essentials of Nuclear Medicine Imaging, 6th Edition by Fred A. Metler Jr. and Milton J. Guiberteau.

  2. A Guide to Radiological Procedures, 5th Edition by Frances Aitchison.

  3. Merrill's Atlas of Radiographic Positioning, 13th Edition by Bruce W. Long et al.

  4. Nuclear Medicine Manual - IAEA.

  5. Textbook of Radiographic Positioning and Related Anatomy, 8th Edition by Kenneth Bontrager and John Lampignano.