Radiation dosimetry in digital breast tomosynthesis: Report of AAPM Tomosynthesis Subcommittee Task Group 223

Abstract

The radiation dose involved in any medical imaging modality that uses ionizing radiation needs to be well understood by the medical physics and clinical community. This is especially true of screening modalities. Digital breast tomosynthesis (DBT) has recently been introduced into the clinic and is being used for screening for breast cancer in the general population. Therefore, it is important that the medical physics community have the required information to be able to understand, estimate, and communicate the radiation dose levels involved in breast tomosynthesis imaging. For this purpose, the American Association of Physicists in Medicine Task Group 223 on Dosimetry in Tomosynthesis Imaging has prepared this report that discusses dosimetry in breast imaging in general, and describes a methodology and provides the data necessary to estimate mean breast glandular dose from a tomosynthesis acquisition. In an effort to maximize familiarity with the procedures and data provided in this Report, the methodology to perform the dose estimation in DBT is based as much as possible on that used in mammography dose estimation.

Review of radiation dose estimates in digital breast tomosynthesis relative to those in two-view full-field digital mammography

“…Examined breasts, using the methods by Dance et al [12], or ACR [30], which uses the model developed by Wu et al [31,32] as a basis for breast dosimetry. These methods are integrated into clinical systems.…”

Dosimetry in x-ray-based breast imaging

“…In 2014, the American Association of Physicists in Medicine (AAPM) published Task Group Report #223 on radiation dosimetry in DBT in which the Wu et al model for mammography was extended for breast tomosynthesis (Sechopoulos et al , 2014). For this, the concept of the RGD(α) and system-specific mean RGD (denoted $\overline{\text{RGD}}$) were used and the values for a generic system and for five commercial and prototype systems are provided.…”

Digital Breast Tomosynthesis: State of the Art

“…Dance et al (76) provided a DBT system-specific factor in determining MGD as per United Kingdom, European, and IAEA protocols. A recent task group report from the American Association of Physicists in Medicine provided similar factors for each DBT system (77). Dosimetry of a system capable of DBT and FFDM acquisitions using the automated exposure control mechanism showed that in general, the MGD from DBT was higher than that from FFDM (77).…”

“…A recent task group report from the American Association of Physicists in Medicine provided similar factors for each DBT system (77). Dosimetry of a system capable of DBT and FFDM acquisitions using the automated exposure control mechanism showed that in general, the MGD from DBT was higher than that from FFDM (77). For the combined DBT plus FFDM mode (hereafter, DBT-FFDM), the MGD determined as per dosimetry protocol used in the United States was lower than the regulatory limit of 3 mGy for a CC-equivalent view of an average breast (78).…”