... of radiation protection）可合理做到的尽量低的原则 (ALARA：as low as reasonably achievable) （3）剂量限值（dose limits） 1．放射实践的正当化（justification of radiological practice）：任何伴有电离辐射的实践，所获得的利益，包括经济的以及各种...
"Specifically, to reach annual radiation doselimits, a passenger would have to receive more than approximately 17, 000 screenings in a 12-month period, which is equivalent to approximately 47 screenings per day, 365 days per year, " the inspector general's office concluded in an executive summary.