An institutional review: dosimetry comparison between simultaneous integrated boost IMRT and VMAT for prostate cancer

Abstract

Purpose: A comparative study was performed about the plan parameters and quality indices between volumetric arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) for the treatment of high-risk prostate cancer patients. The aim of this retrospective study was to compare the two methods of external beam radiotherapy IMRT and VMAT in terms of plan quality and efficacy. Material and method: Fifteen high-risk prostate patients were planned for radiotherapy using 6 MV photon. Three dose levels were contoured having Planning Tumour Volume 1 (PTV1 = 48 Gy), Planning Tumour Volume 2 (PTV2 = 57.6 Gy) and Planning Tumour Volume 3 (PTV3 = 60 Gy). Setup margins were given using the CHIP trial method. The prescribed PTV3 dose was 60 Gy in 20 fractions which is biologically equivalent to 74 Gy in 37 fractions using α/β = 3. In case of IMRT, seven fixed beam angles 30, 60, 105, 180, 255, 300 and 330 were used and the dose was optimised using the sliding window method. In case of rapid arc technique, one or two full arcs were used for dose optimisation while keeping all the dose constraints and other planning parameters same used in IMRT. The plan evaluation parameters and Organ at risks (OARs) doses were calculated using a dose volume histogram (DVH). Results: The average D2, D5, D95 and PTVmean for PTV3 were 61.22, 61.13, 58.12, 60.00 Gy and 62.41 62.24 59.53 61.12 Gy for IMRT and VMAT, respectively. The averages V60 for bladder and V30 for rectum were 22.81, 25 and 67, 65% for IMRT and VMAT, respectively. The average homogeneity index (HI), conformity index (CI) and gradient index (GI) were 1.04, 1.4833, 14.79 and 1.04, 1.704, 7.89 for IMRT and VMAT, respectively. Conclusion: VMAT takes less dose-delivery time and lesser number of monitoring units than IMRT, thus it compensates the intrafractional movements during dose delivery. The Dose GI in VMAT was much better than IMRT. This indicates sharper dose fall off near the normal tissue. No other major differences were observed in terms of plan evaluation parameters between IMRT and VMAT techniques. So, we conclude that VMAT technique is more efficient than IMRT in terms of plan quality and dose delivery.

Analytical dosimetric study of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) for prostate cancer

“…So, VMAT-1A and VMAT-2A techniques shortened the treatment time delivered by 7F IMRT and 9F IMRT techniques which were more comfortable for the patient and helpful in decreasing the machine workload in a busy department. Our data were compared with those published by (Mukhtar et al 2021 ), who found that VMAT was more efficient and had lesser dose delivery time and MU than IMRT.…”

Comparative Study of Eclipse and RayStation Multi-Criteria Optimization-Based Prostate Radiotherapy Treatment Planning Quality

“…Eclipse version 16.1 and RayStation version 12A were used for MCO-based treatment planning for each included CT dataset with TrueBeam linear accelerator and Millennium multi-leave collimator (Varian Medical Systems, Inc., Palo Alto, CA, USA), 2 full arcs and beam energy of 6 MV photons selected [ 31 , 32 ]. The first and second arcs rotated from 175 to 185 degrees counterclockwise, and from 185 to 175 degrees clockwise, respectively.…”

“…Table 2 shows the dose/volume treatment objectives used for the MCO-based planning of the two systems as per in-house protocol [ 17 , 33 ]. Rectum D 50% (V 50 ≤ 50%) and PTV 76 D 98% were selected as trade-off criteria because of their conflicting natures [ 17 , 23 ], i.e., when the dose received by at least 50% of the rectal volume decreased for minimizing the adverse effects of prostate RT, the effectiveness of the prostate cancer treatment also decreased as a result of the reduction of dose received by 98% volume of PTV 76 , and vice versa [ 31 , 32 ].…”

Clinical Differences Among Volumetric Modulated Arc Therapy, Intensity Modulated Radiation Therapy, and 3D- Conformal Radiation Therapy in Prostate Cancer: A Brief Review Study

“…A significantly higher 10-year ST incidence in the pelvis was found in patients using IMRT and VMAT compared with 3D-CRT (10.7% versus 6%). Fifteen high-risk patients with PC treated with 6 MV photon beams were enrolled in the study to compare IMRT and VMAT in terms of plan quality and efficacy [28]. For IMRT, seven fixed beam angles were used, and the dose was optimized using the SW method.…”