Effect of a change in reactor power on response of murine solid tumors in vivo, referring to impact on quiescent tumor cell population. (1st May 2019)

• Record Type: Journal Article
• Authors: Masunaga, Shin-ichiro; Sakurai, Yoshinori; Tanaka, Hiroki; Takata, Takushi; Suzuki, Minoru; Sanada, Yu; Tano, Keizo; Maruhashi, Akira; Ono, Koji
• Is Part Of: International journal of radiation biology. Volume 95:Number 5(2019)
• Page Start: 635
• Page End: 645
• Publication Date: 2019-05-01
• Subjects: Boron neutron capture therapy -- dose rate effect -- reactor power -- quiescent tumor cell -- compound biological effectiveness factor; Radiation -- Physiological effect -- Periodicals; Radiobiology -- Periodicals; 571.45
• DOI: 10.1080/09553002.2019.1558300
• Languages: English
• ISSNs: 0955-3002

Abstract

Abstract: Purpose: To examine the effect of a change in reactor power on the response of solid tumors, referring to impact on quiescent (Q) tumor cell population. Materials and methods: Tumor-bearing mice received 5-bromo-2′-deoxyuridine (BrdU) to label all proliferating (P) tumor cells, and were treated with boronophenylalanine- 10 B (BPA) or sodium mercaptododecaborate- 10 B (BSH). After reactor neutron beam irradiation at a power of 1 or 5 MW with an identical beam spectrum, cells from tumors were isolated and incubated with a cytokinesis blocker. The responses of BrdU-unlabeled Q and total (P + Q) tumor cells were assessed based on the frequencies of micronucleation using immunofluorescence staining for BrdU. Results: After neutron irradiation with or without 10 B-carrier, radio-sensitivity was reduced by decreasing reactor power in both cells, especially in Q cells and after irradiation with BPA. The values of relative and compound biological effectiveness were larger at a power of 5 MW and in Q cells than at a power of 1 MW and in total cells, respectively. The sensitivity difference between total and Q cells was widened when combined with 10 B-carrier, especially with BPA, and through decreasing reactor power. Conclusion: 5 MW is more advantageous than 1 MW for boron neutron capture therapy.