Radiation dose to breast during digital mammography in Tanzania.

The aim of this study was to evaluate the mean glandular dose (MGD), to assess the potential for optimization, and to propose diagnostic reference levels (DRLs). MGD was estimated from air kerma measurements and patient information collected during mammography examinations. The 75th percentile values were determined as the third quartile of the median MGD values for all hospitals, and DRLs set as 75th percentile of MGD values. The estimated median values of MGD ranged from 1.5 to 3.9 mGy for craniocaudal projection for median range of 15-59 mm compressed breast thickness (CBT). For a CBT range of 15-63 mm, the median MGD value was 1.5-5.1 mGy for medio-lateral oblique projection. Comparison with other studies showed that the MGD values obtained in this study were relatively high. The magnitude and wide variation of the exposure parameters suggest existing potential for optimization. The training of radiology staff was identified as a top priority.

Radiation exposure during CT procedures in Tanzania.

The aim of this study was to evaluate optimisation status during common computed tomography (CT) procedures by determining values of volume computed tomography dose index (CTDIvol) and dose-length product (DLP) per examination. Patient and exposure data were collected from the CT console during various CT procedures. The results show that variations in CTDIvol and DLP values were mainly because of differences in the techniques used. The 75th percentile values were set as the third quartile of the median CTDIvol or DLP values for all hospitals. These values of 40.9, 9.0, 9.4 and 16.2 mGy for CTDIvol were determined for head, high-resolution chest, abdomen-pelvis and lumbar spine, respectively. The corresponding DLP values for the same sequence of CT procedures were 900, 360, 487 and 721 mGy.cm, respectively. The updated results provide a basis for optimising the procedures of CT in this country.