PATIENT DOSES IN BONE-MINERAL DENSITOMETRY

Procedures were developed to compute effective dose equivalent (H-E) v alues for patients undergoing bone mineral densitometry(BMD) measureme nts such as dual energy X-ray absorptiometry (DEXA) and quantitative c omputed tomography (QCT). Representative values of H-E were determined for patients undergoing each type of BMD procedure. Typical DEXA meas urements are associated with an H-E of about 2.5 mu Sv. For QCT, the v alues of H-E are 300 mu Sv for single energy techniques and 1 mSv for dual energy techniques. respectively. By comparison, a single well col limated abdominal X-ray examination often taken in conjunction with DE XA studies results in an H-E of about 100 mu Sv. BMD patient doses are at the lower end of the exposure range encountered in diagnostic radi ology. As a result, radiation dose is not a primary factor in choosing the method for BMD determination.