AMBER chest radiography and patient dose measurements

Improved chest imaging has been reported with the usage of AMBER (advanced multiple-beam equalization radiography) equipment but with a higher patient radiation dose compared with conventional chest radiography. Most studies, however, describe dose measurements from phantoms. This study presents a comparison of radiation dose measurements in 57 patients for p.a. projections from an AMBER unit with and without an extra Cu filtration and from a formerly used conventional Siemens chest stand.

Dose measurements were performed with thermoluminescence dosimetry. Entrance surface doses were recorded from 5 dosimeters, placed on the patient's back. Four were placed over the upper and lower lung fields, respectively, and 1 over the mediastinal area. The dose values were then compared with the values obtained from the conventional chest stand and from the measurements with the extra filtration on the AMBER system.

The mean entrance dose for the mediastinal area was 0.25 mSv (range 0.15-0.49). With the extra Cu filtration it was 0.16 mSv (0.07-0.29). For the lung fields the values were 0.19 mSv (0.07-0.44) and 0.10 mSv (0.02-0.31), respectively. For the conventional chest stand the entrance dose to the patient was 0.23 mSv.

AMBER entrance surface doses for the p.a. projection without extra Cu filtration were comparable to the doses obtained with the formerly conventional Siemens chest stand and were well within European recommendations. With extra Cu filtration the AMBER entrance surface doses were reduced by a factor of almost 2.