Radiation Doses and Risks Associated with Mammographic Screening

Abstract

Radiation dose and the associated risk to the breast are being studied in much detail with the aim of justifying breast cancer screening. The mean glandular dose has been proposed as the proper quantity to describe risks incurred by radiation. X. Wu (US) and D. Dance (UK) were the first authors to standardize breast dosimetry and their conversion tables have been used throughout. Doses can be calculated for specific population samples or for individual patients, in which case an accurate estimate of the glandular tissue fraction should be known. From specific DICOM tags in the digital images and access to tube output measurements from the medical physics QA, patient dose assessment can be largely automated. Other (traditional) approaches mimic clinical exposures on a Perspex phantom and use these exposures to estimate the breast dose to a typical breast. Any local data, both patient dose data and doses to Perspex, can these days be compared to an extensive amount of published dose values. Radiation dose and image quality should both be considered in screening applications. Better image quality can have a significant effect on diagnostic performance. As only a small increase in performance (ex. detected fraction) gained can mean an enormous amount of women saved, image quality settings should be optimized and not minimized. Risk benefit investigation should therefore focus on performance rather than dose. For a few screening programs, the benefits could be proven. Emerging technologies should be investigated along the same basic principles.

PPV3 of Suspicious Breast MRI Findings

“…These lesions, although small, were considered suspicious because they were single focus seen in breasts with no significant background parenchymal enhancement, located in the same quadrant as a known biopsy-proven malignancy, or foci that clearly stood out above and beyond the background enhancement pattern. Our evaluation of these foci was in line with the current BI-RADS fifth edition which recommends that foci (small dots that stand out as unique and stand out from background enhancement) should be carefully evaluated (54). Both malignant foci were IDC, and shortterm imaging follow-up would have potentially resulted in a more advanced stage at diagnosis.…”

X-ray dosimetry in breast cancer screening: 2D and 3D mammography

“…Typically, the formalism proposed by Wu et al [11] and its subsequent variations are used in the United States, whereas the European Union uses the formalism proposed by Dance [12]. Although, both the weight fraction and the spatial distribution of fibroglandular tissue are of importance when performing breast dosimetry [13], current dosimetry is based on the weight fraction. Alternatively stated, current dosimetry assumes a homogenous mixture of adipose and fibroglandular tissue and ignores the heterogeneous tissue distribution.…”

“…The Mean Glandular Dose (MGD), also known as the Average Glandular Dose (AGD), is the worldwide recognized quantity that all medical physicists and clinicians use for breast dosimetry protocols and Quality Control (QC) [21,13]. In radiation dosimetry the absorbed dose is defined by the quotient of the mean energy imparted to a small mass element of matter by the radiation field divided by its mass.…”

Dosimetry in Digital Breast Tomosynthesis Evaluated by Monte Carlo Technique

“…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). Due to the patient exposure conditions during a DBT examination, the doses to the organs should be better studied, since there are few available data related to these doses, except for the breast, as a result of this type of examination (Bosmans and Marshall 2013; Baptista et al 2015).…”