Dosimetry analysisof VMATVS IMRT technique in adjuvant radiotherapy of post operated oral cavity cancers in a tertiary care cancer centre.

Dr. Rahul Swarup Singh; Dr. Rajendra Prasad Patel; Dr. Manjula Beck; Dr. Prof. Vivek Choudhary; Dr. Vikram Bali Rathor

Volume : IX, Issue : V, May - 2020

Dosimetry analysisof VMATVS IMRT technique in adjuvant radiotherapy of post operated oral cavity cancers in a tertiary care cancer centre.

Dr. Rahul Swarup Singh, Dr. Rajendra Prasad Patel, Dr. Manjula Beck, Dr. Prof. Vivek Choudhary, Dr. Vikram Bali Rathor

Abstract :

Introduction: Adjuvant Radiotherapy after surgery in head and neck cancer confers best over all survival is the established fact. IMRT is way better than 3DCRT in delivering more homogenous dose with lesser toxicities to the surrounding organs at risk causing less morbidity and significantly increased overall survival and disease free survival. IMRT is associated with more treatment time and in a busy government cancer centre like ours it can be implemented in a limited number of patients. VMAT planning comes out to a promising technique as the delivery time and MU is significantly reduced. At our centre we are treating the head and neck cancer with VMAT technique since 2011. The purpose of this study was to do the dosimetric analysis of both VMAT and IMRT technique in post operated oral cavity cancer patients. Material and method: We selected 60 post operated oral cavity cancer patients who were planned for adjuvant radiation during 2017–18. After simulating them with proper protocol we contoured various treatment volumes and organs at risk and optimized the plan in treatment planning system{1}. Optimization was done with both IMRT and VMAT technique and then dosimetry analysis of target volumes and OARs were evaluated and then plan with better dose distribution was executed for treatment. Result: – double arc VMAT technique yielded better dose distribution than 7 field IMRT. The V95% and V107% in PTV60 and PTV54 were similar in VMAT and IMRT .the average treatment time in double arc VMAT was 3.58 minute where as in a static 7 fields IMRT it was 21.34 minutes (excluding the mode up time). The mean MU of VMAT was 771 and that of IMRT was 1792.13. Conclusion: Double arc VMAT technique for radiotherapy planning of oral cancer provides similar dose distribution to target volumes with better sp� of organs at risk with significant reduction in treatment time when comp� it with IMRT, hence it can be applied for the treatment of oral cavity cancer so as to cater more number of patients under machine.