Radiobiologic significance of response of intratumor quiescent cells in vivo to accelerated carbon ion beams compared with γ-rays and reactor neutron beams
Radiobiologic significance of response of intratumor quiescent cells in vivo to accelerated carbon ion beams compared with γ-rays and reactor neutron beams
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DOI：
10.1016/j.ijrobp.2007.09.021
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发表时间：
2008-01-01
影响因子：
7
通讯作者：
Ono, Koji
中科院分区：
文献类型：
--
作者：
Masunaga, Shin-Ichiro;Ando, Koichi;Ono, Koji
目的：阐明体内瘤内静止细胞对加速碳离子束和反应堆中子束的放射敏感性。方法和材料：鳞状细胞癌VII荷瘤小鼠连续给予5-溴2'-脱氧尿苷标记所有瘤内增殖细胞。接下来，他们接受加速碳离子或T射线高剂量率（HDR）或降低剂量率（RDR）照射。其他荷瘤小鼠接受了反应堆热中子或超热中子的 RDR 照射。 HDR 和 RDR 照射后或 HDR 照射后 12 小时，使用 5-溴-2'-脱氧尿苷免疫荧光染色根据微核频率评估静止细胞的反应。从未经 5-溴-2'-脱氧尿苷处理的肿瘤中测定总肿瘤细胞（增殖加静止）的反应。结果：反应堆中子束或加速碳离子束显着降低了伽马射线照射后总细胞群和静止细胞群之间放射敏感性的差异，尤其是在线性能量转移 (LET) 值较大的情况下。通过延迟测定或降低伽马射线照射剂量率，静止细胞中的修复比总细胞中的修复更清晰，碳离子束可以有效地抑制，尤其是在 LET 更大的情况下。在RDR照射下，具有较大LET值的加速碳离子束的放射敏感性几乎与反应堆热中子束和超热中子束的放射敏感性相似。结论：就包括静止细胞在内的肿瘤细胞整体杀伤效果而言，加速碳离子束，特别是具有较大LET值的加速碳离子束，对于抑制实体瘤内异质性的依赖性以及精确沉积辐射剂量非常有用。 (C) 2008 爱思唯尔公司。
Purpose: To clarify the radiosensitivity of intratumor quiescent cells in vivo to accelerated carbon ion beams and reactor neutron beams.Methods and Materials: Squamous cell carcinoma VII tumor-bearing mice were continuously given 5-bromo2'-deoxyuridine to label all intratumor proliferating cells. Next, they received accelerated carbon ion or T-ray high-dose-rate (HDR) or reduced-dose-rate (RDR) irradiation. Other tumor-bearing mice received reactor thermal or epithermal neutrons with RDR irradiation. Immediately after HDR and RDR irradiation or 12 h after HDR irradiation, the response of quiescent cells was assessed in terms of the micronucleus frequency using immunofluorescence staining for 5-bromo-2'-deoxyuridine. The response of the total (proliferating plus quiescent) tumor cells was determined from the 5-bromo-2'-deoxyuridine nontreated tumors.Results: The difference in radiosensitivity between the total and quiescent cell populations after gamma-ray irradiation was markedly reduced with reactor neutron beams or accelerated carbon ion beams, especially with a greater linear energy transfer (LET) value. Clearer repair in quiescent cells than in total cells through delayed assay or a decrease in the dose rate with gamma-ray irradiation was efficiently inhibited with carbon ion beams, especially with a greater LET. With RDR irradiation, the radiosensitivity to accelerated carbon ion beams with a greater LET was almost similar to that to reactor thermal and epithermal neutron beams.Conclusion: In terms of tumor cell-killing effect as a whole, including quiescent cells, accelerated carbon ion beams, especially with greater LET values, are very useful for suppressing the dependency on the heterogeneity within solid tumors, as well as depositing the radiation dose precisely. (C) 2008 Elsevier Inc.