Comparison of biological effectiveness of carbon-ion beams in Japan and Germany.
OBJECTIVE
To compare the biological effectiveness of 290 MeV/amu carbon-ion beams in Chiba, Japan and in Darmstadt, Germany, given that different methods for beam delivery are used for each.


METHODS
Murine small intestine and human salivary gland tumor (HSG) cells exponentially growing in vitro were irradiated with 6-cm width of spread-out Bragg peaks (SOBPs) adjusted to achieve nearly identical beam depth-dose profiles at the Heavy-Ion Medical Accelerator in Chiba, and the SchwerIonen Synchrotron in Darmstadt. Cell kill efficiencies of carbon ions were measured by colony formation for HSG cells and jejunum crypts survival in mice. Cobalt-60 gamma rays were used as the reference radiation. Isoeffective doses at given survivals were used for relative biological effectiveness (RBE) calculations and interinstitutional comparisons.


RESULTS
Isoeffective D(10) doses (mean +/- standard deviation) of HSG cells ranged from 2.37 +/- 0.14 Gy to 3.47 +/- 0.19 Gy for Chiba and from 2.31 +/- 0.11 Gy to 3.66 +/- 0.17 Gy for Darmstadt. Isoeffective D(10) doses of gut crypts after single doses ranged from 8.25 +/- 0.17 Gy to 10.32 +/- 0.14 Gy for Chiba and from 8.27 +/- 0.10 Gy to 10.27 +/- 0.27 Gy for Darmstadt, whereas isoeffective D(30) doses after three fractionated doses were 9.89 +/- 0.17 Gy through 13.70 +/- 0.54 Gy and 10.14 +/- 0.20 Gy through 13.30 +/- 0.41 Gy for Chiba and Darmstadt, respectively. Overall difference of RBE between the two facilities was 0-5% or 3-7% for gut crypt survival or HSG cell kill, respectively.


CONCLUSIONS
The carbon-ion beams at the National Institute of Radiological Sciences in Chiba, Japan and the Gesellschaft für Schwerionenforschung in Darmstadt, Germany are biologically identical after single and daily fractionated irradiation.
Uzawa
Akiko
A
Heavy-Ion Radiobiology Research Group, Research Center of Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan.
Ando
Koichi
K
Koike
Sachiko
S
Furusawa
Yoshiya
Y
Matsumoto
Yoshitaka
Y
Takai
Nobuhiko
N
Hirayama
Ryoichi
R
Watanabe
Masahiko
M
Scholz
Michael
M
Elsässer
Thilo
T
Peschke
Peter
P
D000818:Animals; D002244:Carbon / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D002470:Cell Survival; D003037:Cobalt Radioisotopes / Q000494:pharmacology; D005260:Female; D005858:Germany; D063193:Heavy Ion Radiotherapy; D006801:Humans; D007414:Intestinal Neoplasms / Q000473:pathology / Q000532:radiotherapy; D007564:Japan; D007583:Jejunum / Q000473:pathology / Q000528:radiation effects*; D051379:Mice; D008809:Mice, Inbred C3H; D012062:Relative Biological Effectiveness; D012468:Salivary Gland Neoplasms / Q000473:pathology / Q000532:radiotherapy; D014410:Tumor Stem Cell Assay / Q000379:methods
D003037:Cobalt Radioisotopes; D002244:Carbon