Cell survival in rat rhabdomyosarcoma tumors irradiated in vivo with extended-peak silicon ions

Journal Article · Fri Oct 01 04:00:00 EDT 1982 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3575856· OSTI ID:6325825

Tenforde, T S; Afzal, S M.J.; Parr, S S; Howard, J; Lyman, J T; Curtis, S B

Cell survival curves were measured by the in vivo to in vitro assay procedure for rat rhabdomyosarcoma tumors irradiated in the distal 4-cm extended-peak region of a 670-MeV/u silicon-ion beam. RBE values determined relative to 225-kVp X rays for the killing of oxygenated tumor cells were 2.1 and 2.2 at the 1 and 10% survival levels, respectively. These RBE values are greater than those obtained previously for extended-peak carbon ions (1.7-1.8), but less than those obtained for extended-peak neon ions (2.5-2.7). This observation indicates that the RBE obtained in the distal-peak region of the 670 MeV/u silicon-ion beam lies beyond the maximum in the TBE verse LETinfinity curve for the killing of oxygenated tumor cells. The TBE value for the killing of hypoxic tumor cells in this beam was 3.6 at both the 1 and 10% survival levels. This TBE value exceeds the previously measured values for both extended-peak carbon ions (2.0) and extended-peak neon ions (3.1-3.3). OER values measured at the 1 and 10% survival levels for silicon ions were 1.2 and 1.3, respectively, compared to 1.7 for neon ions and 1.9 for carbon ions. The significant reduction in oxygen effect for accelerated silicon ions relative to the lighter elements suggests that this beam may be efficacious for the treatment of tumors whose probability of cure is limited by a large fraction of hypoxic cells.

• Research Organization: Lawrence Berkeley Lab., CA
• OSTI ID: 6325825
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 92:1; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560121* -- Radiation Effects on Cells-- External Source-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
BEAMS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
DEPTH DOSE DISTRIBUTIONS
DISEASES
ELECTROMAGNETIC RADIATION
EXPERIMENTAL NEOPLASMS
ION BEAMS
IONIZING RADIATIONS
MAMMALS
MYOSARCOMAS
NEOPLASMS
OXYGEN ENHANCEMENT RATIO
RADIATION DOSE DISTRIBUTIONS
RADIATION EFFECTS
RADIATIONS
RATS
RBE
RHABDOMYOSARCOMAS
RODENTS
SARCOMAS
SILICON 28 BEAMS
SPATIAL DOSE DISTRIBUTIONS
SURVIVAL CURVES
TUMOR CELLS
VERTEBRATES
X RADIATION