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Inactivation of cultured human cells and control of C3H mouse mammary tumors with accelerated nitrogen ions
Author(s) -
Brown Darrell Q.,
Seydel H. Gunter,
Todd Paul
Publication year - 1973
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/1097-0142(197309)32:3<541::aid-cncr2820320305>3.0.co;2-p
Subject(s) - relative biological effectiveness , bragg peak , irradiation , nuclear medicine , radiation therapy , medicine , human kidney , cancer research , pathology , kidney , physics , nuclear physics
Accelerated nitrogen ions (N 7+ ) from the Princeton Particle Accelerator were used to irradiate three dimensional cultures of human kidney T‐l cells and 2 mm thick transplanted C3H mouse mammary tumors. Cell survival was determined at the Bragg peak and at the entrance portion (“plateau”) of the beam using colony formation as the survival criterion. Resulting cell survival curves are compared with those for x‐irradiation under hypoxic and aerobic conditions. The mammary tumors were given single N 7+ fractions of 690, 1400, 2800, and 5500 rads in the Bragg peak. The resulting tumor cure dose for 50% of the animals (TCD 50 .,−120) was determined to be 2400 rads as compared with 5100 rads with x rays. The relative biological effectiveness (RBE) decreased with increasing dose in both systems and ranged between 1.5 and 4.5 for aerobic human cells, 3.7 and 12 for hypoxic human cells, 0.96 and 1.6 for acute mouse skin reaction, 1.9 and 2.5 for mouse tumor control. The RBE for tumor control was consistent with that for hypoxic cells. These results appear to support the proposed use of heavy ions in radiotherapy, at least in cases of small, localized tumors, although further study is needed to determine their effectiveness in the treatment of large volumes, which would require irradiation with multiple Bragg peaks.