DVH Analysis of Cobalt-60 treatment plans incorporating a recently developed MLC

International Journal of Cancer Therapy and Oncology

Roopa Rani Akula¹  Komanduri Ayyangar¹  Palreddy Yadagiri Reddy²  Gangarapu Sri Krishna³  Vuppu Srinivas³  Ayyalasomayajula Anil Kumar³ 

[1] Department of Physics, International Cancer Centre, Bhimavaram;Department of Physics, Osmania University, Hyderabad;Department of Radiotherapy, MNJ Institute of Oncology & Regional Cancer Centre, Hyderabad;

关键词: DVH Analysis, Conformity index, Homogeneity index, Conformation number, MLC Fields, ROPS TPS;   

DOI  :  10.14319/ijcto.43.1

来源: DOAJ

【 摘 要 】

Purpose: The aim of this investigation was to measure the gain in DVH indices when the recently developed MLC was used for Cobalt-60 treatments.

Methods: A prototype multileaf collimator (MLC) that was retrofitted to telecobalt-60 therapy machine was reported and is currently proposed for clinical trials in our institution. Ten patients’ plans that were previously planned through an ECLIPSE^® treatment planning system and were treated with open beams from Cobalt-60 machine were imported into Radiation Oncology Planning System [ROPS] and the dose calculations and dose volume histogram (DVH) analysis were performed. The plans were re-planned using the Cobalt-MLC, a feature available in the ROPS planning system. The DVH analysis consisted of conformity index (CI), homogeneity index (HI) and conformation number (CN). The results of this study are presented in this paper. The analysis specifically aimed at measuring the gain in these indices when the MLC was compared with open beams.

Results: DVH Comparison of ten sites using open and Cobalt MLC fields showed that the use of MLC results in reduced normal tissue dose, while maintaining the GTV dose. Lower value of CI for normal structures was observed demonstrating the sparing of critical organs when MLC was used. The index HI was studied to show the significance of hot spots outside the PTV. Hot spots were observed even with MLC beams for some cases due to less number of fields.

Conclusion: It has been demonstrated through DVH analysis that the use of the recently developed MLC for Cobalt Teletherapy machine results in benefit for the treatment of patients.

【 授权许可】

Unknown