Breast cancer screening: X-ray dosimetry in of 2D and 3D mammography exams

Mammography screening using X-rays for early breast cancer detection, allows saving millions of lives, has been proven in several surveys and studies over the last three decades. The estimation of the radiation dose received by the breast, a radiation-sensitive organ, is quantified using the Mean Glandular Dose (MGD). It is important to understand that the radiation-associated risk from breast x-ray imaging exams is very small. This manuscript reviews the main dosimetric formalisms used to estimate the MGD in mammography and the ongoing efforts to  harmonize the dosimetric protocols, already started by organizations in the world of radiation protection (e.g., ICRP) and medical physics (e.g., AAPM and EFOMP). The health benefits from an early and accurate diagnosis of breast tumors, clearly outweigh the associated radiation-induced cancer risks.

Authors and Affiliations:

S. Di Maria^a,* S. Vedantham^b, P. Vaz^a

^a Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Campus Tecnológico e Nuclear, Estrada Nacional 10, km 139,7, 2695-066 Bobadela LRS, Portugal

^b Department of Medical Imaging, The University of Arizona, Tucson, AZ 85724, US

*corresponding author

Abstract:

According to the World Health Organization (WHO), at the end of 2020, 7.8 million women have been diagnosed with breast cancer in the past 5 years, making it the world’s most prevalent cancer. It is largely recognized and demonstrated that early detection represents the first strategy to follow in the fight against breast cancer. Whilst allowing early detection of breast tumors, exposure of the breast to ionizing radiation may induce detrimental health effects, mainly cancer, but of the order of a few cases per one-hundred thousand mammography exams performed. The effectiveness of mammography screening for early breast cancer detection has been proven in several surveys and studies over the last three decades. The estimation of the radiation dose absorbed in the breast, quantified by the Mean Glandular Dose (MGD), is important to understand the radiation-associated cancer risk from breast x-ray imaging exams. It continues to be the subject of numerous studies and debates, since its accuracy is directly related to risk estimation and for optimizing breast cancer screening programs.

This manuscript reviews the main dosimetric formalisms used to estimate the MGD in mammography, and to highlight the continuing efforts to reduce the absorbed dose over the last forty years and the associated radiation induced cancer risks. The dosimetry protocols were formulated initially for mammography. Digital breast tomosynthesis (DBT) either in conjunction with synthesized digital mammogram (SDM) or with digital mammography (DM), is routinely used in many breast cancer screening programs and consequently the dosimetry protocols were extended for these techniques.

In summary, breast cancer screening using X-rays are life-saving procedures, saving the lives of millions of individuals per year, clearly outweighing the theoretical risk of a few cancers induced by ionizing radiation due to the x-ray examinations.

Journal: European Journal of Radiology (Elsevier) 

Link: https://www.sciencedirect.com/science/article/pii/S0720048X22001280