Science Links Japan | Evaluation and Optimization of Therapeutic SOBP Beam by Cultured Cells. III. Estimation of RBE for Small Fractionation with High Dose Exposure.

Evaluation and Optimization of Therapeutic SOBP Beam by Cultured Cells. III. Estimation of RBE for Small Fractionation with High Dose Exposure.

Accession number;00A0557809

Title;Evaluation and Optimization of Therapeutic SOBP Beam by Cultured Cells. III. Estimation of RBE for Small Fractionation with High Dose Exposure.

Author; FURUSAWA YOSHIYA (National Inst. of Radiological Sciences) SAITO MIZUHO (Chiba Univ., Grad. Sch.) SHIMAO DAISUKE (Ibaraki-kenritsu Iryo Daigaku) KUBOTA NOBUO (Ibaraki-kenritsu Iryo Daigaku) KANAI TATSUAKI (National Inst. of Radiological Sciences)

Journal Title;NIRS-M (Natl Inst Radiol Sci)

Journal Code:Z0881A

ISSN:

VOL.;NO.133;PAGE.59-60(1999)

Figure&Table&Reference;FIG.3, REF.1

Pub. Country;Japan

Language;Japanese

Abstract;LET-RBE relationship at low survival (or high dose) level is required to design new ridge-filters for SOBP beams at radiation therapy of eye-melanomas, where the number of fractionation will be small and the dose for each exposure will be high. New method to obtain LET-RBE relationship was established in this study, using a usual cell survival data and spheroid survival data. Monolayer culture and spheroid culture of a human melanoma HMV-I cells were used, and exposed to X-rays and 35 keV/.MU.m carbon beams at HIMAC. The survival data from monolayer cells was linked together with that from spheroids, and survival curves less than 10-5 survival level could be obtained. The plots could be fitted well with following equation that produced from the LQ model and the hit model. S=exp(-.ALPHA.D)[1-{1-exp(-D/D0)}n] The RBE for 35 keV/.MU.m beam to X-rays obtained from survival curves that reconstructed with the constants (.+-., D0, n) of the equation, decreased with the survival level at higher survival region (>10%), and showed no big change below the level. (author abst.)

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