Dosimetric Methods for and Influence of Exposure Parameters on the Establishment of Reference Doses in Mammography

Evaluation of scattered radiation in mammography examination with Si detector

“…Scattering factor values approximated from our Monte Carlo calculations are slightly higher and differ within 10% from the values used for calculations of the in-breast absorbed doses in mammography [6]. The differences can be explained taking into account that BSF is calculated for the ESD and SF is recalculated from total dose, absorbed in LiF, which includes not only scattered photon fraction from the PMMA surface but additionally small fraction of Compton scattered photons in the detector material.…”

“…Entrance surface dose was measured using Si detector (UNFORS Mamo, calibrated 2005 02 24 at UNFORS laboratory), which was placed laterally centred 60 mm from the chest wall side (as required in European Protocol on Dosimetry in Mammography [6]) on the top of the exposed PMMA phantom. PMMA phantom with a surface area of 240×150 mm 2 was combined to various thicknesses ranging from 20 to 80 mm and was used to simulate patient's breast thickness during mammography examinations.…”

“…Keeping this dose as low as reasonably achievable [4,5] or reducing it during medical examinations, is one of the most important problems in diagnostic radiology. It is impossible to measure absorbed dose in biological structure directly [6]. This dose can be recalculated using measured or simulated entrance surface dose (ESD) or entrance surface kerma (ESAK), X-ray spectrum parameters and applying different conversion factors, which are measured or simulated by Monte Carlo calculations.…”

“…Measured ESD includes the contribution of backscatter radiation expressed in terms of backscatter factor (BSF): [6,11,12]. They have been approved and now are recommended for the use in mammography practice [6,13].…”

“…Measured ESD includes the contribution of backscatter radiation expressed in terms of backscatter factor (BSF): [6,11,12]. They have been approved and now are recommended for the use in mammography practice [6,13]. Despite of fact that semiconductor devices are used for in vitro phantom measurements [4], the contribution of backscattered radiation to the dose absorbed in semiconductor detectors is not investigated sufficiently.…”