In vivo determinations of RBE in a high energy modulated proton beam using normal tissue reactions and fractionated dose schedules

Journal Article · Sat Jan 01 04:00:00 EST 1977 · Int. J. Radiat. Oncol., Biol. Phys.; (United States)

DOI:https://doi.org/10.1016/0360-3016(77)90118-3· OSTI ID:7090272

Tepper, J ^[1]; Verhey, L; Goitein, M; Suit, H D; Phil, D; Koehler, A M

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1. Massachusetts General Hospital, Boston

In preparation for a clinical trial of proton radiation therapy, we have performed a series of in vivo radiobiological experiments to determine the relative biological effectiveness (RBE) of protons as compared to /sup 60/Co using normal tissue reaction in mice as the biological endpoint. The first assay studied was the survival of jejunal crypt cells in both the spread out Bragg Peak (SOBP) and the unmodulated portion (valley) of the proton beam. Experiments were performed using both single fraction and 20 fraction (3 hr between fractions) irradiations. These data demonstrate an RBE in the SOBP and the proton valley of 1.23 and 1.17 respectively for the 20 fraction experiment, and 1.19 and 1.13 for the single fraction experiment. These RBE values are only minimally dependent on the endpoint used for the analysis. The second assay was the acute skin reaction in the mouse thigh after 20 fractions of irradiation. Analyzing the average response from 11 to 30 days after irradiation the RBE was 1.13, and analyzing the dose for 50% of the animals to reach a score of 2.5 indicated an RBE of 1.14. Analysis of late effects by measurement of thigh epilation indicated an RBE of 1.14 while analysis of contraction was inadequate for an RBE estimate. These experiments indicate an RBE of approximately 1.20 for protons (compared to /sup 60/Co) when analyzing mouse jejunum and approximately 1.13 when analyzing acute and late skin reaction. They also indicate that the RBE is relatively independent of fraction size in the range studied, and independent of whether the irradiation is performed in the center of a 10 cm wide SOBP or in the valley of the proton beam.

• OSTI ID: 7090272
• Journal Information: Int. J. Radiat. Oncol., Biol. Phys.; (United States), Journal Name: Int. J. Radiat. Oncol., Biol. Phys.; (United States) Vol. 2:11-12; ISSN IOBPD
• Country of Publication: United States
• Language: English

Related Subjects

560152* -- Radiation Effects on Animals-- Animals
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACUTE EXPOSURE
ACUTE IRRADIATION
ANIMAL CELLS
ANIMALS
BARYONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BODY
BODY AREAS
COBALT 60
COBALT ISOTOPES
COMPARATIVE EVALUATIONS
CRYPT CELLS
DELAYED RADIATION EFFECTS
DIGESTIVE SYSTEM
EARLY RADIATION EFFECTS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
EXTERNAL IRRADIATION
FERMIONS
FRACTIONATED IRRADIATION
GAMMA RADIATION
GASTROINTESTINAL TRACT
HADRONS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
INTESTINES
IONIZING RADIATIONS
IRRADIATION
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEGS
LIMBS
LOCAL IRRADIATION
MAMMALS
MICE
MINUTES LIVING RADIOISOTOPES
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
ORGANS
PROTONS
RADIATION EFFECTS
RADIATIONS
RADIOISOTOPES
RBE
RODENTS
SKIN
SMALL INTESTINE
SOMATIC CELLS
SURVIVAL TIME
VERTEBRATES
WHOLE-BODY IRRADIATION
YEARS LIVING RADIOISOTOPES