Effect of negative pions on the proliferative capacity of ascites tumor cells (lymphoma) grown in vivo

Technical Report · Thu Mar 30 04:00:00 EST 1967

DOI:https://doi.org/10.2172/159358· OSTI ID:159358

Feola, J M; Richman, C; Raju, M R; Curtis, S B; Lawrence, J H

We have attempted to determine the relative biological effectiveness (RBE) of negative pions in the Bragg-peak region as compared to the plateau region and to gamma rays. We irradiated LAF{sub 1} mice, bearing 5-day-old lymphoma ascites tumors, in the peak and plateau regions of a 90-MeV pion beam for 40 hours in temperature-controlled holders. The animals were then sacrificed; lymphoma cells were withdrawn and titrated into adult female LAF{sub 1} mice. The proliferative capacity of the irradiated tumor cells was evaluated after 8 weeks by observing the percentage of animals developing ascites tumors. Surviving fractions were then calculated from LD{sub 50}`s of control and irradiated animals. Radiation doses in the 50 plateau region were measured with LiF dosimeters calibrated against cobalt-60 gamma rays. We calculated peak doses from those at the plateau, using a measured average peak-to-plateau ionization ratio of 1.5. Doses in the plateau region ranged from 145 to 250 rads; doses in the peak region ranged from 220 to 380 rads. The survival curve for cells irradiated in the peak region gave a D{sub 0} of 65 {plus_minus} 15 rads. The plateau points were not reliable. A replicate experiment was performed using Co{sup 60} {gamma}-rays, yielding a survival-curve D{sub 0} of 350 {plus_minus} 50 rads. If the {gamma}-ray D{sub 0} is taken as a baseline, an RBE of 5.4 {plus_minus} 1.8 is obtained for negative pions in the peak region, based on the ratio of-peak-region D{sub 0} to Co{sup 60} D{sub 0}.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• OSTI ID: 159358
• Report Number(s): UCRL--17478; ON: DE95013615
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
EXPERIMENTAL NEOPLASMS
LYMPHOMAS
MICE
PIONS MINUS
RADIATION DOSES
RADIOTHERAPY
RBE
SURVIVAL CURVES