Belli M, Cera F, Cherubini R, Dalla Vecchia M, Haque A M, Ianzini F, Moschini G, Sapora O, Simone G, Tabocchini M A, Tiveron P
Laboratorio di Fisica, Istituto Superiore di Sanità, INFN-Sezione Sanità, Rome, Italy.
Int J Radiat Biol. 1998 Oct;74(4):501-9. doi: 10.1080/095530098141375.
RBE-LET relationships for cell inactivation and hprt mutation in V79 cells have been studied with mono-energetic low-energy proton beams at the radiobiological facility of the INFN-Laboratori Nazionali di Legnaro (LNL), Padova, Italy.
V79 cells were irradiated in mono-layer on mylar coated stainless steel petri dishes, in air. Inactivation data were obtained at 7.7, 34.6 and 37.8 keV/microm and hprt mutation was studied at 7 7 and 37.8 keV/microm. Additional data were also collected for both the end points with the proton LET already considered in our previous publications, namely 11.0, 20.0 and 30.5 keV/microm.
A maximum in the RBE-LET relationship for cell inactivation was found at around 31 keV/microm, while the RBE for mutation induction increased continuously with LET.
The proton RBE-LET relationship for cell inactivation is shifted to lower LET values compared with that for heavier ions. For mutation induction, protons of LET equal to 7.7keV/microm gave an RBE value comparable with that obtained by helium ions of about 20 keV/microm. Mutagenicity and lethality caused by protons at low doses in the LET range 7.7-31 keV/microm were proportional, while the data at 37.8 keV/microm suggest that this may not hold at higher LET values.
在意大利帕多瓦市的意大利国家核物理研究所莱尼亚罗国家实验室（LNL）的放射生物学设施中，使用单能低能质子束研究了V79细胞中细胞失活和hprt突变的相对生物学效应（RBE）与传能线密度（LET）的关系。
V79细胞在空气中置于涂有聚酯薄膜的不锈钢培养皿上单层照射。在7.7、34.6和37.8 keV/μm处获得失活数据，并在7.7和37.8 keV/μm处研究hprt突变。还收集了我们之前出版物中已考虑的质子LET的两个终点的其他数据，即11.0、20.0和30.5 keV/μm。
细胞失活的RBE-LET关系在约31 keV/μm处出现最大值，而突变诱导的RBE随LET持续增加。
与重离子相比，质子细胞失活的RBE-LET关系向更低的LET值偏移。对于突变诱导，LET等于7.7keV/μm的质子产生的RBE值与约20 keV/μm的氦离子获得的RBE值相当。在7.7 - 31 keV/μm的LET范围内，低剂量质子引起的致突变性和致死性是成比例的，而37.8 keV/μm的数据表明在更高的LET值下可能并非如此。
