A heavy particle comparative study. Part II: cell survival versus depth

Abstract

Cell-survival measurements with depth of penetration were made for a series of incident doses of proton, helium, carbon, neon, argon, negative pion, neutron, and 60Co photon beams. Cultured human cells (T1) suspended in a gel-containing medium were used, and the measurements were found to be very useful in facilitating the design of ridge filters to produce iso-effects in the region of interest. Heavy charged particle beams (proton, helium, carbon, neon, and negative pion) were found to produce similar cell killing with depth of penetration. Because of saturation effects at higher LET, argon ions were less effective in killing aerated cells at depth, compared with other heavy charged-particle beams. Cell killing at depth in the region of interest, compared with that at the entrance, was not significantly different for single-field exposures when the Bragg peaks were broadened to cover a width of 10 cm. However, when two opposed fields with overlapping peaks were used, a large enhancement in killing was obtained in the peak region.

Helium ions for radiotherapy? Physical and biological verifications of a novel treatment modality

“…39 Another experiment reports RBE values of 1.2 ± 0.2 determined at the center of a target volume extending from 10.5 to 21 cm, irradiated with 5.5 Gy. 40 These RBE values are compatible with our findings, at least in the center of the target volume. One should keep in mind, however, that their experimental conditions are quite different from ours as far as cell lines, dose per fraction, and simulated tumor locations are concerned.…”

Temporal Lobe (TL) Damage Following Surgery and High-Dose Photon and Proton Irradiation in 96 Patients Affected by Chordomas and Chondrosarcomas of the Base of the Skull

“…The proton dose is reported in CGE, which is the physical dose times the relative biological effectiveness of protons, relative to 60 cobalt, of 1.10 (7). Many experimental determinations of RBE have been made, using cell cultures and in animals, and have yielded a range (0.78 -1.32) of RBEs for protons (7,8). The value of 1.10 was selected from early experiments, has been used since the beginning of the clinical treatments at HCL-MGH, and seems to be consistent with the clinical response of patients.…”

Relative biological effectiveness (RBE) values for proton beam therapy. Variations as a function of biological endpoint, dose, and linear energy transfer

“…A subset of publications listed α x and β x for the reference x-ray radiation as well as the α and β values so that only the LET d had to be simulated based on the beam energy or the information of the range and modulation width of the Bragg curve (Raju et al 1978a, Urano et al 1980, Satoh et al 1986, Blomquist et al 1993, Yashkin et al 1995, Gueulette et al 1996, Coutrakon et al 1997, Tang et al 1997, Matsumura et al 1999, Bettega et al 2000, Ando et al 2001, Schettino et al 2001, Calugaru et al 2011, Kase et al 2013, Matsumoto et al 2014. Some reports did not mention any of the parameters α x , β x , α, β, or LET d so that the survival curves had to be extracted from the publications and fitted (using matlab (Mathworks Inc.)) in addition to simulating LET d values (Robertson et al 1975, Hall et al 1978, Williams et al 1978, Raju et al 1978b, Bettega et al 1979, Sakamoto et al 1980, Fuhrman Conti et al 1988, Ogata et al 2005, Kagawa et al 2002, Baek et al 2008, Butterworth 2012, Grosse et al 2014, Zhang et al 2013, Aoki-Nakano 2014. In some incidents the LET d values were reported but the α and β values for all measured conditions as a function of proton energy or position in the Bragg curve had to be manually extracted (Wainson et al 1972, Inada et al 1981, Hei et al 1988a, Wouters et al 1996, Ogheri et al 1997…”