FDA UPDATES GUIDANCE ON MEASURING X-RAY SCAN DOSES
Manufacturers and assemblers of X-ray computed tomography (CT) equipment may use an alternate measure of the computed tomography dose index (CTDI) when scanning patients, a new FDA guidance says. The guidance is part of the effort to move industry toward standardizing dosing measurements for the radiation-emitting devices.
The 2002 National Conference on CT Dose Reduction recommended standardization of CT dose terminology following input from organizations including the National Electrical Manufacturers Association and the International Electrotechnical Commission, the guidance says.
In keeping with this trend, the guidance explains that CT equipment manufacturers may now substitute measured values of an alternate measure, CTDI 100, for the required values of CTDI.
CTDI is an index that indicates the magnitude of radiation doses to be delivered and the changes in doses depending on the model of CT scanner and the conditions of operation, the guidance says.
The document, "Guidance for Industry, FDA Staff and Third Parties -- Provision for Alternate Measure of the Computed Tomography Dose Index to Assure Compliance with the Dose Information Requirements of the Federal Performance Standard for Computed Tomography," can be viewed at www.fda.gov/cdrh/ocer/guidance/1609.pdf (http://www.fda.gov/cdrh/ocer/guidance/1609.pdf).