Keywords:
Radiation physics, Radioprotection / Radiation dose, CT, Dosimetry, Radiation safety, Physics
Authors:
T. Johnson, R. P. Marcus, K. Neumair, M. F. Reiser, F. Bamberg; Munich/DE
DOI:
10.1594/ecr2012/C-0788
Methods and Materials
An Alderson phantom (RSD Radiology Support Devices) was equipped with 52 thermoluminiscent detectors evenly distributed through the abdomen.
The phantom was scanned on aSiemens Definition Flash CTin three different set-ups:
(I) The original phantom using automatic voltage adaptation and tube current modulation.
(Fig.
1)
(II) The phantom embedded in a circumferential layer of pork fat 10 cm thick with automatically increased voltage and current.
(Fig.2 )
(III) Original phantom using the same CT settings as for the “obese” phantom.
Dose was calculated using organ-specific weighing factors according to ICRP-103 and by multiplying DLP with standard conversion factors (k=0.015 mSv/mGy*cm).
Image quality was assessed sujectively and by image noise measurement.