Abstract
The broad application of low energy X-rays below about 50 keV in radiation therapy and diagnostics and especially in mammography substantiates the precise determination of their relative biological effectiveness (RBE). A quality factor of 1 is stated for photons of all energies in the International Commission on Radiological Protection Recommendations. However, the RBE of low-energy X-rays compared to high-energy photons was found to be dependent on photon energy, cell line and endpoints studied, hence varying from less than one up to about four. In the present study, the human mammary epithelial cell line MCF-12A has been chosen due to the implementation of the results in the estimation of risk from mammography procedures. The RBE of 25 kV X-rays (W anode, 0.3 mm Al filter) relative to 200 kV X-rays (W anode, 0.5 mm Cu filter) was determined for clonogenic survival in the dose range 1–10 Gy and micronuclei (MN) induction in the range 0.5–3.5 Gy. The RBE for clonogenic survival was found to be significantly higher than 1 for surviving fractions in the range 0.005 < S < 0.2. The RBE decreased with increasing survival, with an RBE0.1 at 10% survival of 1.13 ± 0.03. The effectiveness of soft X-rays for MN induction was found to be 1.40 ± 0.07 for the fraction of binuclear cells (BNC) with MN and 1.44 ± 0.17 for the number of MN per BNC. In contrast, the RBE determined from the number of MN per MN-bearing BNC was found to be 1.08 ± 0.32. This indicates that the effectiveness of 25 kV X-rays results from an increase in the number of damaged cells, which, however, do not have higher number of MN per cell.
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References
ICRP Publication 60 (1991) 1990 Recommendations of the International Commission on Radiological Protection. Annals of the ICRP 21(1–3). Pergamon Press, Oxford
Zeitz L, Kim SH, Kim JH, Detko JF (1977) Determination of relative biological effectiveness (RBE) of soft X-rays. Radiat Res 70:552–563
Bistrović M, Bišćan M, Viculin T (1986) RBE of 20(kV X-rays determined for survival of V 79 cells. Radiother Oncol 7:175–180
Hoshi M, Antoku S, Nakamura N, Russel WJ, Miller RC, Sawada S, Mizuno M, Nishio S (1988) Soft X-rays dosimetry and RBE for survival of Chinese hamster V79 cells. Int J Radiat Biol 54:577–591
Spadinger I, Palcic B (1992) The relative biological effectiveness of 6°Co γ-rays, 55 kVp X-rays, 250 kVp X-rays, and 11(MeV electrons at low doses. Int J Radiat Biol 61:345–353
Frankenberg-Schwager M, Garg I, Frankenberg D, Greve B, Severin E, Uthe D, Göhde W (2002) Mutagenicity of low-filtered 30 kVp X-rays, mammography X-rays and conventional X-rays in cultured mammalian cells. Int J Radiat Biol 78:781–789
Panteleeva A, Słonina D, Brankovic K, Spekl K, Pawelke J, Hoinkis C, Dörr W (2003) Clonogenic survival of human keratinocytes and rodent fibroblasts after irradiation with 25 kV X-rays. Radiat Environ Biophys 42:95–100
Virsik RP, Harder D, Hansmann I (1977) The RBE of 30 kV X-rays for the induction of dicentric chromosomes in human lymphocytes. Radiat Environ Biophys 14:109–121
Sasaki MS, Kobayashi K, Hieda K, Yamada T, Ejima Y, Maezawa H, Furusawa Y, Ito T, Okada S (1989) Induction of chromosome aberrations in human lymphocytes by monochromatic X-rays of quantum energy between 4.8 and 14.6 keV. Int J Radiat Biol 56:975–988
Schmid E, Regulla D, Kramer HM, Harder D (2002) The effect of 29 kV X-rays on the dose response of chromosome aberrations in human lymphocytes. Radiat Res 158:771–777
Krumrey M, Ulm G, Schmid E (2004) Dicentric chromosomes in monolayers of human lymphocytes produced by monochromatized synchrotron radiation with photon energies from 1.83 keV to 17.4 keV. Radiat Environ Biophys 43:1–6
Frankenberg D, Kelnhofer K, Bär K, Frankenberg-Schwager M (2002) Enhanced neoplastic transformation by mammography X-rays relative to 200 kVp X-rays: indication for a strong dependence on photon energy of the RBE(M) for various end points. Radiat Res 157:99–105. Erratum in: Radiat Res 158:126
Göggelmann W, Jacobsen C, Panzer W, Walsh L, Roos M, Schmid E (2003) Re-evaluation of the RBE of 29 kV X-rays (mammography X-rays) relative to 220 kV X-rays using neoplastic transformation of human CGL1-hybrid cells. Radiat Environ Biophys 42:175–182
Heyes GH, Mill AJ (2004) The neoplastic transformation potential of mammography X-rays and atomic bomb spectrum radiation. Radiat Res 162:120–127
Brenner DJ, Amols HI (1989) Enhanced risk from low-energy screen-film mammography X-rays. Br J Radiol 62:910–914
Verhaegen F, Reniers B (2004) Microdosimetric analysis of various mammography spectra: lineal energy distributions and ionization cluster analysis. Radiat Res 162:592–599
Kellerer AM (2002) Electron spectra and the RBE of X-Rays. Radiat Res 158:13–22
Paine TM, Soule HD, Pauley RJ, Dawson PJ (1992) Characterization of epithelial phenotypes in mortal and immortal human breast cells. Int J Cancer 50:463–473
Fenech M (1993) The cytokinesis-block micronucleus technique: a detailed description of the method and its application to genotoxicity studies in human populations. Mutat Res 285:35–44
Slonina D, Spekl K, Panteleeva A, Brankovic K, Hoinkis C, Dörr W (2003) Induction of micronuclei in human fibroblasts and keratinocytes by 25 kV X-rays. Radiat Environ Biophys 42:55–61
NIST physical reference data (1998) X-ray and gamma-ray data http://www.physics.nist.gov/PhysRefData/
Boone JM, Seibert JA (1997) An accurate method for computer-generating tungsten anode X-ray spectra from 30 to 140 kV. Med Phys 24:1661–1670
Wolfram Research (2000) Mathematica 4.1. http://www.wolfram.com
Marples B, Joiner MC (1993) The response of Chinese hamster V79 cells to low radiation doses: evidence of enhanced sensitivity of the whole cell population. Radiat Res 133:41–51
Hill MA (2004) The variation in biological effectiveness of X-rays and gamma rays with energy. Radiat Prot Dosim 112:471–481
Verhaegen F, Vral A (1994) Sensitivity of micronucleus induction in human lymphocytes to low-LET radiation qualities: RBE and correlation of RBE and LET. Radiat Res 139:208–213
Schmid E, Krumrey M, Ulm G, Roos H, Regulla D (2003) The maximum low-dose RBE of 17.4 and 40 keV monochromatic X-rays for the induction of dicentric chromosomes in human peripheral lymphocytes. Radiat Res 160:499–504
Lewis DA, Mayhugh BM, Qin Y, Trott K, Mendonca MS (2001) Production of delayed death and neoplastic transformation in CGL1 cells by radiation-induced bystander effects. Radiat Res 156:251–258
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Lehnert, A., Lessmann, E., Pawelke, J. et al. RBE of 25 kV X-rays for the survival and induction of micronuclei in the human mammary epithelial cell line MCF-12A. Radiat Environ Biophys 45, 253–260 (2006). https://doi.org/10.1007/s00411-006-0062-3
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DOI: https://doi.org/10.1007/s00411-006-0062-3