ICRU Report 74, Patient Dosimetry for X Rays used in Medical Imaging


The present Report is the first report published by the ICRU that deals with patient dosimetry for x rays used in diagnostic medical imaging. The impetus for this report derives from the broad and systemic application of x rays for diagnostic and interventional imaging. The increasing number of patients that benefits from radiology and the increasing number and types of procedures that are applied to these patients have resulted in a dramatic increase of the population dose, which, in developed countries, often exceeds the natural radiation levels. The situation in developing countries will sooner or later exhibit the same trend.

This Report presents specifications of x-ray beams and quantities,and units for dose measurement and calculation in medical x-ray imaging, including application-specific quantities, and new symbols. It addresses measurement methods for normalization quantities and for quantities recommended for the establishment and use of diagnostic reference levels. It presents methods for determining organ and tissue doses as well as doses in localized regions of organs and tissues, including detailed information on dose-conversion coefficients for x-ray imaging fields. This is the first ICRU Report dealing with methods for patient dosimetry of x rays used in medical imaging. Whereas some of the dosimetric concepts and techniques used in radiotherapy have been successfully employed for medical imaging using x rays, additional dosimetric quantities and measurement methods are required for patient dosimetry associated with procedures such as radiography, fluoroscopy, CT, and mammography.