Therapeutic Nuclear Medicine and Patient Management
What the exam tests
Therapy items test radionuclide selection, dose strategy, pre-treatment assessment, radiation safety instructions, release criteria, and follow-up for toxicity. Expect I-131, Lu-177 DOTATATE, Y-90 microspheres, Ra-223, and bone-pain palliation.
Core rules
- I-131 is used for hyperthyroidism and differentiated thyroid cancer; pregnancy testing, lactation cessation, and thyroid hormone/TSH planning are mandatory. Activity ranges from fixed outpatient doses to dosimetry-guided ablation.
- Lu-177 DOTATATE targets somatostatin receptors; renal protection with amino acid infusion and monitoring of renal and hematologic toxicity are standard. Ra-223 is an alpha emitter for bone metastases and requires hematologic monitoring.
- Y-90 microspheres are delivered by interventional radiology; pre-treatment angiography and lung shunt evaluation limit non-target embolization.
- Patient release after therapy follows dose-rate or dose-to-others criteria, with written instructions on close contact, sleeping, travel, and bodily fluids.
- Document pregnancy test, counseling, consent, administered activity, and follow-up plan.
Worked example
After 100 mCi I-131, a patient's exposure rate is 0.045 mSv/h at 1 m. That is below the common 0.05 mSv/h release threshold, so release is permitted with instructions. If the rate were 0.08 mSv/h, the patient would need to remain isolated until decay or meet the alternative effective-dose criterion. The reasoning requires the measured distance and units to be stated; a rate at 0.3 m cannot be compared directly with a 1 m criterion.
Traps that cost marks
- Treating a fertile patient without a documented pregnancy test.
- Continuing breastfeeding after I-131.
- Ignoring renal function before Lu-177 or hematologic reserve before Ra-223.
- Giving release instructions verbally without documentation.