Biomaterial Database

RBE of 50 MV scanned bremsstrahlung beams determined using clonogenic assay. 2002

L M Persson, and B K Lind, and M R Edgren, and I Hedlöf, and A Brahme

Medical Radiation Physics, Department of Oncology-Pathology, Karolinska Institutet and Stockholm University, Box 260, SE 17176, Stockholm, Sweden. linda@radfys.ks.se

OBJECTIVE In order to compare the biological effectiveness of a 50 MV scanned bremsstrahlung beam to (60)Co and 6 MV photons, the survival of Chinese hamster cells (V79-379A), human normal fibroblasts cells (GSH(+/+)) and human small cell lung cancer cells (U-1690) were analysed. METHODS Cells were irradiated in vitro under aerobic conditions in a plastic phantom. Dose to the cells was determined using ferrous sulphate and ionization chamber dosimetry. A number of cell survival models were fitted to the experimental data, including the standard LQ model with and without the induced repair. In particular, a new model treating damage and repair separately was used in combination with a new technique for accurate RBE determination. RESULTS The measured RBE for the three cell lines were 0.988 (0.984-0.992), 0.999 (0.996-1.002) and 1.013 (1.009-1.016) for V79-379A, GSH(+/+) and U-1690 respectively and thus 50 MV scanned beams did not differ more than a fraction of a per cent from conventional therapy beams. CONCLUSIONS The present study gives RBE consistent with previously calculated RBEs based on photonuclear reaction cross-sections of high-energy photons.

UI	MeSH Term	Description	Entries
D008175	Lung Neoplasms	Tumors or cancer of the LUNG.	Cancer of Lung,Lung Cancer,Pulmonary Cancer,Pulmonary Neoplasms,Cancer of the Lung,Neoplasms, Lung,Neoplasms, Pulmonary,Cancer, Lung,Cancer, Pulmonary,Cancers, Lung,Cancers, Pulmonary,Lung Cancers,Lung Neoplasm,Neoplasm, Lung,Neoplasm, Pulmonary,Pulmonary Cancers,Pulmonary Neoplasm
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D011882	Radiotherapy, High-Energy	Radiotherapy using high-energy (megavolt or higher) ionizing radiation. Types of radiation include gamma rays, produced by a radioisotope within a teletherapy unit; x-rays, electrons, protons, alpha particles (helium ions) and heavy charged ions, produced by particle acceleration; and neutrons and pi-mesons (pions), produced as secondary particles following bombardment of a target with a primary particle.	Megavolt Radiotherapy,High-Energy Radiotherapy,Radiotherapy, Megavolt,High Energy Radiotherapy,Radiotherapy, High Energy
D012062	Relative Biological Effectiveness	The ratio of radiation dosages required to produce identical change based on a formula comparing other types of radiation with that of gamma or roentgen rays.	Biological Effectiveness, Relative,Effectiveness, Biologic Relative,Effectiveness, Biological Relative,Relative Biologic Effectiveness,Biologic Effectiveness, Relative,Biologic Relative Effectiveness,Biological Relative Effectiveness,Effectiveness, Relative Biologic,Effectiveness, Relative Biological,Relative Effectiveness, Biologic
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D002470	Cell Survival	The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.	Cell Viability,Cell Viabilities,Survival, Cell,Viabilities, Cell,Viability, Cell
D003037	Cobalt Radioisotopes	Unstable isotopes of cobalt that decay or disintegrate emitting radiation. Co atoms with atomic weights of 54-64, except 59, are radioactive cobalt isotopes.	Radioisotopes, Cobalt
D003114	Colony-Forming Units Assay	A cytologic technique for measuring the functional capacity of stem cells by assaying their activity.	Clonogenic Cell Assay,Stem Cell Assay,Clonogenic Cell Assays,Colony Forming Units Assays,Colony-Forming Units Assays,Stem Cell Assays,Assay, Clonogenic Cell,Assay, Colony-Forming Units,Assay, Stem Cell,Assays, Clonogenic Cell,Assays, Colony-Forming Units,Assays, Stem Cell,Colony Forming Units Assay
D004307	Dose-Response Relationship, Radiation	The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.	Dose Response Relationship, Radiation,Dose-Response Relationships, Radiation,Radiation Dose-Response Relationship,Radiation Dose-Response Relationships,Relationship, Radiation Dose-Response,Relationships, Radiation Dose-Response
D006224	Cricetinae	A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.	Cricetus,Hamsters,Hamster