PURPOSE: In many countries, breast cancer screening programs based on periodic mammography exist, giving a large group of women regularly a small dose of ionizing radiation. In order to assess the benefit/risk ratio of those programs the relative biological effectiveness (RBE) of mammography X-rays needs to be determined. MATERIALS AND METHODS: Blood of five healthy donors was irradiated in vitro with 30 kV X-rays and (60)Co γ-rays with doses between 5 and 2000 mGy. The phosphorylated histone subtype H2A isoform X-foci (γH2AX-foci) technique was used to quantify the number of DNA double-strand breaks (DSB) after irradiation. Chromosomal damage resulting from non- or misrepaired DNA DSB was quantified with the micronucleus (MN)-assay and the sensitivity was improved by counting only centromere negative micronuclei (MNCM-). RESULTS: The threshold detection dose obtained with the γH2AX-foci test was 10 mGy for mammography X-rays compared to 50 mGy for γ-rays. With the MN-assay respectively MN-centromere-assay threshold detection doses of 100, respectively, 50 mGy were obtained for mammography X-rays compared to 200 respectively 100 mGy for γ-rays. An RBE of 1.4 was obtained with the γH2AX-foci assay. With the MN-assays low-dose RBE values between 3 and 4 were determined. CONCLUSION: Our results indicate that exposure to mammography X-rays resulted in a modest increase in the induction of DSB compared to γ-rays. However, due to the higher linear energy transfer (LET) of mammography X-rays more clustered DNA damage is produced that is more difficult to repair and results in a more pronounced increase in micronucleus formation.
PURPOSE: In many countries, breast cancer screening programs based on periodic mammography exist, giving a large group of women regularly a small dose of ionizing radiation. In order to assess the benefit/risk ratio of those programs the relative biological effectiveness (RBE) of mammography X-rays needs to be determined. MATERIALS AND METHODS: Blood of five healthy donors was irradiated in vitro with 30 kV X-rays and (60)Co γ-rays with doses between 5 and 2000 mGy. The phosphorylated histone subtype H2A isoform X-foci (γH2AX-foci) technique was used to quantify the number of DNA double-strand breaks (DSB) after irradiation. Chromosomal damage resulting from non- or misrepaired DNA DSB was quantified with the micronucleus (MN)-assay and the sensitivity was improved by counting only centromere negative micronuclei (MNCM-). RESULTS: The threshold detection dose obtained with the γH2AX-foci test was 10 mGy for mammography X-rays compared to 50 mGy for γ-rays. With the MN-assay respectively MN-centromere-assay threshold detection doses of 100, respectively, 50 mGy were obtained for mammography X-rays compared to 200 respectively 100 mGy for γ-rays. An RBE of 1.4 was obtained with the γH2AX-foci assay. With the MN-assays low-dose RBE values between 3 and 4 were determined. CONCLUSION: Our results indicate that exposure to mammography X-rays resulted in a modest increase in the induction of DSB compared to γ-rays. However, due to the higher linear energy transfer (LET) of mammography X-rays more clustered DNA damage is produced that is more difficult to repair and results in a more pronounced increase in micronucleus formation.
Authors: Lynn Feys; Benedicte Descamps; Christian Vanhove; Anne Vral; Liv Veldeman; Stefan Vermeulen; Carlos De Wagter; Marc Bracke; Olivier De Wever Journal: Oncotarget Date: 2015-09-29
Authors: Matus Durdik; Pavol Kosik; Eva Markova; Alexandra Somsedikova; Beata Gajdosechova; Ekaterina Nikitina; Eva Horvathova; Katarina Kozics; Devra Davis; Igor Belyaev Journal: Sci Rep Date: 2019-11-07 Impact factor: 4.379
Authors: Annelot Baert; Julie Depuydt; Tom Van Maerken; Bruce Poppe; Fransiska Malfait; Katrien Storm; Jenneke van den Ende; Tim Van Damme; Sylvia De Nobele; Gianpaolo Perletti; Kim De Leeneer; Kathleen B M Claes; Anne Vral Journal: Breast Cancer Res Date: 2016-05-17 Impact factor: 6.466