Comparative study of dose distribution between carbon ion radiotherapy and photon radiotherapy for head and neck tumor

Radiat Med. 2008 Aug;26(7):415-21. doi: 10.1007/s11604-008-0252-9. Epub 2008 Sep 4.


Purpose: A comparative treatment planning study has been performed between carbon ion radiotherapy (CIRT) and photon radiotherapy [three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT)] to assess the potential improvements and limitations that could result for locally advanced, nonresectable head and neck tumors.

Materials and methods: Seven patients, originally treated with CIRT, were randomly selected for the comparative study. The evaluations analyzed using dose-volume histogram parameters, conformity index, inhomogeneity coefficient, and dose to the organs at risk (OARs).

Results: The mean conformity index was 1.46, 1.43, and 1.22 for 3D-CRT, IMRT, and CIRT, respectively. The mean inhomogeneity coefficient was 0.05, 0.07, and 0.02 for 3D-CRT, IMRT, and CIRT respectively. Photon plans resulted in greater volumes of normal tissues at 10% to 95% isodose levels compared with the corresponding carbon ion plans where the volumes increased by a factor of 1.2 to 2.7 for 3D-CRT and 1.2 to 2.0 for IMRT.

Conclusion: CIRT has the potential to improve the target dose conformity, inhomogeneity coefficient, and OAR sparing when compared with 3D-CRT and IMRT. Compared with 3D-CRT, normal tissue exposure was reduced mainly in the mid-to low-isodose levels using IMRT. Additional improvement was obtained using CIRT.

Publication types

  • Comparative Study

MeSH terms

  • Carbon Radioisotopes / therapeutic use
  • Head and Neck Neoplasms / radiotherapy*
  • Humans
  • Photons / therapeutic use
  • Radiotherapy Dosage
  • Radiotherapy Planning, Computer-Assisted / methods*
  • Radiotherapy Planning, Computer-Assisted / statistics & numerical data
  • Radiotherapy, Conformal / methods*
  • Radiotherapy, Intensity-Modulated / methods


  • Carbon Radioisotopes