title: Forward-scattered radiation from the compression paddle should be considered in glandular dose estimations.
abstract: From major protocols on dosimetry in mammography, there is no doubt that the incident air kerma should be evaluated without backscattered radiation to the dosemeter. However, forward-scattered radiation from the compression paddle is neglected. The aim of this work was to analyse the contribution of forward-scattered radiation for typical air kerma measurements. Measurements of forward-scatter were performed with a plane-parallel ionisation chamber on four mammography units. The forward-scatter contribution to the air kerma was 2-10 % and increased with the compression paddle thickness, but also with the half-value layer value. For incident air kerma in mammography, it can be as important to consider forward-scattered as backscattered radiation. If an ionisation chamber is used, the compression paddle should be in contact with the chamber; otherwise the air kerma and absorbed dose will be underestimated. If a dosemeter based on semiconductors with much less sensitivity to scattered radiation is used, it is suggested that a forward-scatter factor (FSF) is applied. Based on the results of this work, FSF = 1.06 will lead to a maximum error of ~4 %.
authors.affiliation: Department of Medical Radiation Physics, Lund University, Skåne University Hospital Malmö, SE-205 02 Malmö, Sweden. bengt.hemdal@med.lu.se
authors.forename: Bengt
authors.initials: B
authors.lastname: Hemdal
mesh_terms: D000388:Air; D001940:Breast / Q000473:pathology* / Q000528:radiation effects*; D002138:Calibration; D005260:Female; D006801:Humans; D008327:Mammography; D009010:Monte Carlo Method; D011829:Radiation Dosage; D011874:Radiometry; D012542:Scattering, Radiation