title: The dosimetric impact of different photon beam energy on RapidArc radiotherapy planning for cervix carcinoma.
abstract: The main purpose of this study is to know the effect of three different photon energies viz., 6, 10, and 15 mega voltage (MV) on RapidArc (RA) planning for deep-seated cervix tumor and to develop clinically acceptable RA plans with suitable photon energy. RA plans were generated for 6, 10, and 15 MV photon energies for twenty patients reported with cervix carcinoma. RA plans were evaluated in terms of planning target volume (PTV) coverage, dose to organs at risk (OARs), conformity index (CI), homogeneity index (HI), gradient measure, external volume index of dose distribution produced, total number of monitor units (MUs), nontumor integral dose (ID), and low dose volume of normal tissue. A two-sample paired t-test was performed to compare the dosimetric parameters of RA plans. Irrespective of photon energy used for RA planning, plans were dosimetrically similar in terms of PTV coverage, OARs sparing, CI and HI. The numbers of MUs were 13.4 ± 1.4% and 18.2 ± 1.5% higher and IDs were 2.7 ± 0.8% and 3.7 ± 0.9% higher in 6 MV plans in comparison to that in the 10 and 15 MV plans, respectively. V1Gy, V2Gy, V3Gy, and V4Gy were higher in 6 MV plans in comparison to that in 10 and 15 MV plans. Based on this study, 6 MV photon beam is a good choice for RA planning in case of cervix carcinoma, as it does not deliver additional exposure to patients caused by photoneutrons produced in high energy beams.
authors: Department of Radiotherapy, Medical Physics Division, Rajiv Gandhi Cancer Institute and Research Centre, Rohini, New Delhi, India.
authors: Lalit
authors: L
authors: Kumar
authors: Department of Radiotherapy, Medical Physics Division, Rajiv Gandhi Cancer Institute and Research Centre, Rohini, New Delhi, India.
authors: Girigesh
authors: G
authors: Yadav
authors: Department of Radiotherapy, Medical Physics Division, Rajiv Gandhi Cancer Institute and Research Centre, Rohini, New Delhi, India.
authors: Kothanda
authors: K
authors: Raman
authors: Department of Radiotherapy, Medical Physics Division, Rajiv Gandhi Cancer Institute and Research Centre, Rohini, New Delhi, India.
authors: Manindra
authors: M
authors: Bhushan
authors: Department of Radiotherapy, Medical Physics Division, Rajiv Gandhi Cancer Institute and Research Centre, Rohini, New Delhi, India.
authors: Manoj
authors: M
authors: Pal
keywords: Dose distribution; RapidArc; neutron dose; photon energy