The therapeutic ratio in BNCT: Assessment using the Rat 9L gliosarcoma brain tumor and spinal cord models
- Brookhaven National Lab., Upton, NY (United States)
- Univ. of Oxford (United Kingdom). CRC Normal Tissue Radiobiological Research Group
During any radiation therapy, the therapeutic tumor dose is limited by the tolerance of the surrounding normal tissue within the treatment volume. The short ranges of the products of the {sup 10}B(n,{alpha}){sup 7}Li reaction produced during boron neutron capture therapy (BNCT) present an opportunity to increase the therapeutic ratio (tumor dose/normal tissue dose) to levels unprecedented in photon radiotherapy. The mixed radiation field produced during BNCT comprises radiations with different linear energy transfer (LET) and different relative biological effectiveness (RBE). The short ranges of the two high-LET products of the `B(n,a)`Li reaction make the microdistribution of the boron relative to target cell nuclei of particular importance. Due to the tissue specific distribution of different boron compounds, the term RBE is inappropriate in defining the biological effectiveness of the {sup 10}B(n,{alpha}){sup 7}Li reaction. To distinguish these differences from true RBEs we have used the term {open_quotes}compound biological effectiveness{close_quotes} (CBE) factor. The latter can be defined as the product of the true, geometry-independent, RBE for these particles times a {open_quotes}boron localization factor{close_quotes}, which will most likely be different for each particular boron compound. To express the total BNCT dose in a common unit, and to compare BNCT doses with the effects of conventional photon irradiation, multiplicative factors (RBEs and CBEs) are applied to the physical absorbed radiation doses from each high-LET component. The total effective BNCT dose is then expressed as the sum of RBE-corrected physical absorbed doses with the unit Gray-equivalent (Gy-Eq).
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 390616
- Report Number(s):
- BNL-63408; CONF-9410281-8; ON: DE97000006; TRN: 96:029177
- Resource Relation:
- Conference: 6. international symposium on neutron capture therapy for cancer, Kobe (Japan), 31 Oct - 4 Nov 1994; Other Information: PBD: 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Major compound-dependent variations of sup 10 B(n. alpha. ) sup 7 Li RBE for the 9L RAT gliosarcoma in vitro and in vivo
Derivations of relative biological effectiveness for the high-let radiations produced during boron neutron capture irradiations of the 9L rat gliosarcoma in vitro and in vivo