Abstract
Normalized glandular dose (DgN) coefficients obtained using homogeneous breast phantoms are commonly used in breast dosimetry for mammography. However, glandular tissue is heterogeneously distributed in the breast. This study aimed to construct three-layer heterogeneous mammographic phantoms (THEPs) to examine the effect of glandular distribution on DgN coefficient. Each layer of THEPs was set to 25%, 50%, or 75% glandular fraction to emulate heterogeneous glandular distribution. Monte Carlo simulation was performed to attain mean glandular dose (MGD) and air kerma at 22–36 kVp and W/Al, W/Rh, and W/Ag target–filter combinations. The heterogeneous DgN coefficient was calculated as functions of the mean glandular fraction (MGF), breast thickness, tube voltage, and half-value layer. At 50% MGF, the heterogeneous DgN coefficients for W/Al, W/Rh, and W/Ag differed by 40.3%, 36.7%, and 31.2%. At 9-cm breast thickness, the DgN values of superior and inferior glandular distributions were 25.4% higher and 29.2% lower than those of uniform distribution. The proposed THEPs can be integrated with conventional breast dosimetry to consider the heterogeneous glandular distribution in clinical practice.
Highlights
Normalized glandular dose (DgN) coefficients obtained using homogeneous breast phantoms are commonly used in breast dosimetry for mammography
three-layer heterogeneous mammographic phantoms (THEPs) possess the characteristic of heterogeneous glandular distribution, and the corresponding DgN coefficients can be integrated into the existing breast dosimetric systems
The results suggest that the effect of glandular distribution on DgN coefficient slightly decreases with increasing tube voltage
Summary
Normalized glandular dose (DgN) coefficients obtained using homogeneous breast phantoms are commonly used in breast dosimetry for mammography. The heterogeneous DgN coefficient was calculated as functions of the mean glandular fraction (MGF), breast thickness, tube voltage, and half-value layer. One of the most critical parameters is the normalized glandular dose (DgN) coefficient, which is obtained using Monte Carlo simulation of mean glandular dose (MGD) in a breast phantom[4]. Complete heterogeneous DgN data sets for various tube voltages, target–filter combinations, beam qualities, breast thicknesses, and glandular distributions are still scarce for MGD and diagnostic reference level (DRL) assessment[17]. This study proposed digital three-layer heterogeneous mammographic phantoms (THEPs) and used the Monte Carlo method to obtain DgN coefficients for different target–filter combinations in mammography. THEPs possess the characteristic of heterogeneous glandular distribution, and the corresponding DgN coefficients can be integrated into the existing breast dosimetric systems
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
