Radiotherapy & Nuclear Medicine

Topics in this chapter

• Radiotherapy Physics and Biology
• External Beam Radiotherapy Techniques
• Brachytherapy and Fractionation
• Radiation Safety and Toxicity
• Nuclear Medicine Imaging
• Therapeutic Radionuclides and Clinical Use

Practice questions

1. Question 1Q-3B2CE4

   A 55-year-old male is diagnosed with localized carcinoma of the prostate and is planned for external beam radiotherapy. Which of the following is the most important radiobiological advantage of using high-energy photon beams or particle beams compared to superficial X-rays?

   1. A.Higher surface dose
   2. B.Skin-sparing effect due to buildup region
   3. C.Complete absence of exit dose
   4. D.Shorter overall treatment time
   See the answer and solution
2. Question 2Q-FFAEF2

   Which of the following radioisotopes is most commonly used for targeted radionuclide therapy in metastatic castration-resistant prostate cancer with bone metastases, primarily acting as an alpha emitter?

   1. A.Iodine-131
   2. B.Lutetium-177
   3. C.Radium-223
   4. D.Strontium-89
   See the answer and solution
3. Question 3Q-A88463

   In the evaluation of suspected neuroendocrine tumors, which of the following radiotracers is most specific and sensitive for molecular imaging via PET-CT?

   1. A.Fluorodeoxyglucose (18F-FDG)
   2. B.Gallium-68 DOTATATE
   3. C.Technetium-99m MDP
   4. D.Gallium-68 PSMA
   See the answer and solution
4. Question 4Q-EAE739

   A patient undergoing fractionated external beam radiotherapy for head and neck squamous cell carcinoma develops acute xerostomia. Which of the following salivary glands is most critical to spare during treatment planning to prevent permanent severe xerostomia?

   1. A.Sublingual gland
   2. B.Parotid gland
   3. C.Submandibular gland
   4. D.Minor palatal salivary glands
   See the answer and solution
5. Question 5Q-797C84

   What is the primary radiobiological mechanism by which fractionation of radiotherapy enhances the therapeutic ratio between normal tissues and tumors?

   1. A.Induction of permanent cell cycle arrest in G0 phase
   2. B.Reassortment, repair, repopulation, and reoxygenation
   3. C.Irreversible depletion of tumor stem cell niches via direct hyperthermia
   4. D.Complete elimination of the hypoxic fraction in a single high dose
   See the answer and solution