Free Nuclear Medicine Exam Questions That Helps Candidates Pass

Comprehensive and Detailed Explanation: Investigation levels are administrative thresholds (often 10–30 % of the regulatory limit) established by the licensee. When a dosimeter reading exceeds an investigation level, the radiation safety officer reviews the worker’s activities, technique, shielding use, and workload to determine the cause and to implement corrective actions if needed. This proactive process supports ALARA by identifying problems before regulatory limits are approached. Investigation levels do not replace regulatory limits and do not automatically result in restriction from work. Documentation of each investigation is retained as part of the radiation-protection program records.

Comprehensive and Detailed Explanation: Any sealed source that shows evidence of leakage (detectable removable contamination) must be immediately withdrawn from use, placed in a sealed container, and reported to the radiation safety officer. The RSO will arrange for proper testing, return to the manufacturer, or disposal as radioactive waste. Continuing to use a leaking source can spread contamination throughout the department and expose personnel. Regular wipe tests of sealed sources are required by regulation. Technologists must know the location of all sealed sources, perform or assist with leak testing according to schedule, and never attempt to open or repair a sealed source. Prompt reporting protects staff and maintains regulatory compliance.

Comprehensive and Detailed Explanation: Mo-99/Tc-99m generators are eluted with sterile, pyrogen-free 0.9 % sodium chloride (normal saline). The saline removes Tc-99m pertechnetate from the alumina column while the parent Mo-99 remains bound. Other solvents can damage the column or introduce impurities. Technologists must use the volume recommended by the manufacturer, maintain aseptic technique, and perform required Mo-99 and aluminum breakthrough tests on the eluate. Proper elution technique maximizes yield and ensures the eluate is suitable for clinical use.

Comprehensive and Detailed Explanation: Tc-99m pertechnetate is actively taken up by gastric mucosa and is therefore the agent of choice for localizing Meckel’s diverticulum that contains ectopic gastric tissue. Sequential abdominal images are obtained for 30–60 minutes after injection. Pharmacologic premedication (H2 blockers, pentagastrin, or glucagon) may be used according to protocol to enhance uptake or reduce motility. Sulfur colloid, MDP, and MAA have different biodistributions and are not appropriate. Technologists must know the correct timing, positioning, and possible interventions so that ectopic mucosa is reliably detected and physiologic gastric activity is correctly interpreted.

Comprehensive and Detailed Explanation: Commercial MAA kits contain a fixed number of particles. For patients with pulmonary hypertension, right-to-left shunt, or pediatric patients, the number of particles administered must be reduced (often to 100,000–200,000). This is accomplished by reconstituting the kit according to instructions and then diluting a portion of the suspension with saline so that the desired particle number is contained in the injected volume. The activity is adjusted accordingly. Increasing boiling time or adding stannous ion does not change particle number. Technologists must calculate both activity and particle number and document the dilution. Administering too many particles can further compromise an already limited pulmonary vascular bed.