Relative biological effectiveness of carbon ions for local tumor control of a radioresistant prostate carcinoma in the rat

Int J Radiat Oncol Biol Phys. 2011 Jan 1;79(1):239-46. doi: 10.1016/j.ijrobp.2010.07.1976. Epub 2010 Oct 8.


Purpose: To study the relative biological effectiveness (RBE) of carbon ion beams relative to X-rays for local tumor control in a syngeneic rat prostate tumor (Dunning subline R3327-AT1).

Methods and materials: A total of 198 animals with tumors in the distal thigh were treated with increasing single and split doses of either (12)C ions or photons using a 20-mm spread-out Bragg peak. Endpoints of the study were local control (no tumor recurrence within 300 days) and volumetric changes after irradiation. The resulting values for D(50) (dose at 50% tumor control probability) were used to determine RBE values.

Results: The D(50) values for single doses were 32.9 ± 0.9 Gy for (12)C ions and 75.7 ± 1.6 Gy for photons. The respective values for split doses were 38.0 ± 2.3 Gy and 90.6 ± 2.3 Gy. The corresponding RBE values were 2.30 ± 0.08 for single and 2.38 ± 0.16 for split doses. The most prominent side effects were dry and moist desquamation of the skin, which disappeared within weeks.

Conclusion: The study confirmed the effectiveness of carbon ion therapy for severely radioresistant tumors. For 1- and 2-fraction photon and (12)C ion radiation, we have established individual D(50) values for local tumor control as well as related RBE values.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / pathology
  • Adenocarcinoma / radiotherapy*
  • Adenocarcinoma / secondary
  • Animals
  • Carbon / adverse effects
  • Carbon / therapeutic use*
  • Cell Line, Tumor
  • Male
  • Photons / adverse effects
  • Photons / therapeutic use
  • Prostatic Neoplasms / pathology
  • Prostatic Neoplasms / radiotherapy*
  • Radiation Injuries, Experimental / pathology
  • Radiation Tolerance*
  • Radiation, Ionizing
  • Radiodermatitis / pathology
  • Rats
  • Relative Biological Effectiveness*
  • Skin / radiation effects
  • Tumor Burden / radiation effects
  • Xenograft Model Antitumor Assays / methods


  • Carbon