Dosimetry in x-ray-based breast imaging

Abstract

The estimation of the mean glandular dose to the breast (MGD) for x-ray based imaging modalities forms an essential part of quality control and is needed for risk estimation and for system design and optimisation. This review considers the development of methods for estimating the MGD for mammography, digital breast tomosynthesis (DBT) and dedicated breast CT (DBCT). Almost all of the methodology used employs Monte Carlo calculated conversion factors to relate the measurable quantity, generally the incident air kerma, to the MGD. After a review of the size and composition of the female breast, the various mathematical models used are discussed, with particular emphasis on models for mammography. These range from simple geometrical shapes, to the more recent complex models based on patient DBCT examinations. The possibility of patient-specific dose estimates is considered as well as special diagnostic views and the effect of breast implants. Calculations using the complex models show that the MGD for mammography is overestimated by about 30% when the simple models are used. The design and uses of breast-simulating test phantoms for measuring incident air kerma are outlined and comparisons made between patient and phantom-based dose estimates. The most widely used national and international dosimetry protocols for mammography are based on different simple geometrical models of the breast, and harmonisation of these protocols using more complex breast models is desirable.

Zaštita Od Jonizirajućeg Zračenja Kod Medicinske Ekspozicije

“…Obrađena su 652 pacijenta, i to 206 pacijenata tretiranih 3DCRT i 446 pacijenata tretiranih IMRT, a rezultati su pokazali da IMRT pluća u odnosu na 3DCRT omogućava signifikantno bolju lokoregionalnu kontrolu bolesti i reducira toksicitet na pluća, dok nije bilo signifikantne razlike u ukupnom preživljenju i toksicitetu na ezofagus za stadij III NSCLC [14]. I druga istraživanja potvrđuju prednost IMRT u odnosu na 3DCRT, kako u smislu isporuke veće doze na ciljni volumen tako i poštede zdravih tkiva [15][16][17]. Iradijacija pleure zbog malignog mezotelioma ranije je značila istovremenu isporuku visokih doza i na zdravi parenhim pluća.…”

“…In order to achieve conditions necessary for a high-quality mammography each of its procedures has to be justified and optimized [13]. Most studies and researches regarding mammography tend to define risks and benefits [14][15][16][17] caused by application of radiation in mammography. The size which best describes risks for glandular tissue caused by application of radiation in mammography is called mean glandular dose (MGD).…”

Risk Assessment From Ionizing Radiation in Mammography

“…In order to achieve conditions necessary for a high-quality mammography each of its procedures has to be justified and optimized [13]. Most studies and researches regarding mammography tend to define risks and benefits [14][15][16][17] caused by application of radiation in mammography. The size which best describes risks for glandular tissue caused by application of radiation in mammography is called mean glandular dose (MGD).…”

Breast-density measurement using photon-counting spectral mammography

“…The administration of preventive and adjuvant chemotherapy can be related to risk, and the effect of drugs such as tamoxifen and raloxifene that simultaneously reduce the susceptibility to breast cancer and breast density, can be monitored. Further, breast density has the potential to facilitate clinical trials by working as a surrogate for breast cancer, and it is an important input parameter to dose calculations …”