Generation of low-flux X-ray micro-planar beams and their biological effect on a murine subcutaneous tumor model

Zhengshan Hong, Junko Zenkoh, Biao Le, Ariungerel Gerelchuluun, Kenshi Suzuki, Takashi Moritake, Masakazu Washio, Junji Urakawa, Koji Tsuboi*

*この研究の対応する著者

研究成果: Article査読

2 被引用数 (Scopus)

抄録

We generated low-flux X-ray micro-planar beams (MPBs) using a laboratory-scale industrial X-ray generator (60 kV/20 mA) with custom-made collimators with three different peak/pitch widths (50/200 μm, 100/400 μm, 50/400 μm). To evaluate normal skin reactions, the thighs of C3H/HeN mice were exposed to 100 and 200 Gy MPBs in comparison with broad beams (20, 30, 40, 50, 60 Gy). Antitumor effects of MPBs were evaluated in C3H/HeN mice with subcutaneous tumors (SCCVII). After the tumors were irradiated with 100 and 200 Gy MPBs and 20 and 30 Gy broad beams, the tumor sizes were measured and survival analyses were performed. In addition, the tumors were excised and immunohistochemically examined to detect γ-H2AX, ki67 and CD34. It was shown that antitumor effects of 200 Gy MPBs at 50/200 μm and 100/400 μm were significantly greater than those of 20 Gy broad beams, and were comparable with 30 Gy broad beams. γ-H2AX-positive cells demonstrated clear stripe-patterns after MPB irradiation; the pattern gradually faded and intermixed over 24 h. The chronological changes in ki67 positivity did not differ between MPBs and broad beams, whereas the CD34-positive area decreased significantly more in MPBs than in broad beams. In addition, it was shown that skin injury after MPB irradiation was significantly milder when compared with broad-beam irradiation at equivalent doses for achieving the same tumor control effect. Bystander effect and tumor vessel injury may be the mechanism contributing to the efficacy of MPBs.

本文言語English
ページ(範囲)768-776
ページ数9
ジャーナルJournal of radiation research
56
5
DOI
出版ステータスPublished - 2015 9 1

ASJC Scopus subject areas

  • 放射線
  • 放射線学、核医学およびイメージング
  • 健康、毒物学および変異誘発

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