Assessment of scatter radiation dose and absorbed doses in eye lens and thyroid gland during digital breast tomosynthesis

Abstract

Digital breast tomosynthesis (DBT) is an alternative tool for breast cancer screening; however, the magnitude of peripheral organs dose is not well known. This study aimed to measure scattered dose and estimate organ dose during mammography under conventional (CM) and Tomo (TM) modes in a specific DBT system. Optically stimulated luminescence dosimeters (OSLDs), whose responses were corrected using a parallel‐plate ionization chamber, were pasted on the surface of custom‐made polymethyl methacrylate (PMMA) and RANDO phantoms to measure entrance surface air kerma (ESAK). ESAK measurements were also acquired with a 4.5‐cm thick breast phantom for a standard mammogram. Organ dose conversion factors (CFD) were determined as ratio of air kerma at a specific depth to that at the surface for the PMMA phantom and multiplied by the ratio of mass energy absorption coefficients of tissue to air. Normalized eye lens and thyroid gland doses were calculated using the RANDO phantom by multiplying CFD and ESAK values. Maximum variability in OSLD response to scatter radiation from the DBT system was 33% in the W/Rh spectrum and variations in scattered dose distribution were observed between CM and TM. The CFD values for eye lens and thyroid gland ranged between 0.58 to 0.66 and 0.29 to 0.33, respectively. Mean organ doses for two‐view unilateral imaging were 0.24 (CM) and 0.18 (TM) μGy/mAs for the eye lens and 0.24 (CM) and 0.25 (TM) μGy/mAs for the thyroid gland. Higher organ doses were observed during TM compared to CM as the automatic exposure control (AEC) system resulted in greater total mAs values in TM.

Estimated risk of radiation-induced cancer following breast screening employing tomosynthesis and digital mammography

“…In the validation of the Monte Carlo simulation model used in this work, our dose results were compared with the ones shown in table 4 of the work of Chusin et al [36], obtained for DBT and DM modes. Even if an absolute comparison between these two works is not strictly possible (i.e.…”

Technical note: Characteristics of the energy spread kernels of scattered radiation in an x‐ray room

“…1 Knowing the energy spectrum of ionizing radiation inside an x-ray room is essential to optimize the design of radiation protection measures. [2][3][4][5][6][7][8][9][10] These measures must be taken for the protection of the patient 11,12 and the professionals inside the room [13][14][15][16][17][18][19][20][21][22] and the professionals and the public outside it. 23 In this work, Monte Carlo simulations are carried out to characterize the scattered radiation inside the x-ray room.…”

“…Knowing the energy spectrum of ionizing radiation inside an x‐ray room is essential to optimize the design of radiation protection measures 2–10 . These measures must be taken for the protection of the patient 11,12 and the professionals inside the room 13–22 and the professionals and the public outside it 23 …”

Dosimetry in Digital Breast Tomosynthesis Evaluated by Monte Carlo Technique

“…During a DBT examination, individual low-dose exposures are performed with the x-ray tube at different angles relative to the plane of the compressed breast (Chusin et al 2019). In DBT, the possible variation in the radiation dose due to the change in geometry (i.e., change in position of the x-ray tube) during acquisition should be well addressed and studied (Rodrigues et al 2015; Sechopoulos et al 2014).…”