The relative biological effectiveness of fractionated doses of fast neutrons (42 MeVd----Be) for normal tissues in the pig. II. Late effects on cutaneous and subcutaneous tissues.
The relative biological effectiveness of fractionated doses of fast neutrons (42 MeVd----Be) for normal tissues in the pig. II. Late effects on cutaneous and subcutaneous tissues.
复制标题
分次剂量的快中子 (42 MeVd----Be) 对猪正常组织的相对生物学效应。
DOI：
10.1259/0007-1285-63-754-760
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
G. Wiernik
中科院分区：
文献类型：
--
作者：
J. W. Hopewell;D. W. H. Barnes;M. E. C. Robbins;M. Corp;J. M. Sansom;C. Young;G. Wiernik
用单次和分次剂量的X射线(250千伏)和快中子(42 MeVd-Bc)照射猪的皮肤和皮下组织，通过测量相对场长的变化来评价其远期效应。照射后每隔26-104周测定一次。对于X射线分割照射，从等效应剂量(ED50)与分割数的对数对数图得到的平均分割指数N为0.41。这与评估期无关，没有明显的时间因素。然而，指数N确实随着效应水平的不同而变化，在0.33-0.51之间。当相对场长度减少大于或等于10%时，效果最好。假设细胞存活的线性二次模型有效，则α/β比值为1.95Gy.然而，对于最不严重的损害程度，该模型对数据的拟合较差，对于这些损害，α/β比率与零没有显著差异。与单次剂量相比，快中子照射显示出大于或等于6个分数的剂量的分馏效应很小。分30次给药与6次给药相比，等效剂量无明显增加。对所用快中子能量的晚期皮肤和皮下损伤的相对生物学效应不随评估期而变化，即26-52周与65-104周，并且与先前在照射后12-20周高剂量后的缺血性真皮坏死所获得的结果没有显著差异。
The late effects of irradiation with single and fractionated doses of X rays (250 kV) and fast neutrons (42 MeVd----Bc), on the cutaneous and subcutaneous tissues of the pig, have been evaluated from measurements of changes in relative field length. These were determined at intervals of 26-104 weeks after irradiation. For fractionated irradiation with X rays the average fractions exponent, N, obtained from a log-log plot of iso-effect dose (ED50) against fraction number was 0.41. This was independent of the period of assessment, with no significant indication of a time factor. However, the exponent N did vary with the level of effect and was in the range 0.33-0.51. It was greatest for a greater than or equal to 10% reduction in relative field length. Assuming the validity of the linear quadratic model of cell survival, the alpha/beta ratio was 1.95 Gy. However, this model fitted the data less well for the least severe levels of damage, and for these the alpha/beta ratios were not significantly different from zero. Irradiation with fast neutrons showed a small effect of fractionation for doses given in greater than or equal to 6 fractions compared with a single dose. There was no significant increase in iso-effect dose when the dose was given in 30 fractions compared with 6 fractions. The relative biological effectiveness for late cutaneous and subcutaneous damage for the energy of fast neutrons used did not vary with the period of assessment, i.e. 26-52 weeks compared with 65-104 weeks, and was not significantly different from that previously obtained for ischaemic dermal necrosis, seen after higher doses, at 12-20 weeks after irradiation.
影响因子：
5.7
作者：
BENTZEN, SM;THAMES, HD;OVERGAARD, M
通讯作者：
OVERGAARD, M