What is the standard maximum acceptable percentage for energy resolution measured with 137Cs for a NaI(Tl) scintillation detector?

The standard maximum acceptable percentage for energy resolution measured with 137Cs for a NaI(Tl) scintillation detector is typically set at 12%. Energy resolution is a crucial characteristic of a detector, indicating how well the system can differentiate between different gamma-ray energies. The energy resolution is often expressed as a percentage of the full-width at half-maximum (FWHM) of the peak observed in the energy spectrum.

In the case of NaI(Tl) detectors, which are widely used in nuclear medicine due to their effectiveness in detecting gamma radiation, maintaining a high energy resolution is essential for accurate quantification and imaging. The 12% threshold reflects the performance of these scintillation detectors, balancing sensitivity and differentiation capabilities necessary for effective diagnostics.

Other options represent higher energy resolution percentages, which would indicate a broader peak and thus a less precise measurement capability, making them less desirable for clinical applications where accurate energy discrimination is necessary. Therefore, the choice of 12% aligns with the performance standards established for NaI(Tl) detectors in nuclear medicine practice.