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.

In this research work, a simple homemade cubic phantom was designed to validate the Image-Guided Radiotherapy (IGRT) set up and verified with the help of tungsten fiducial markers (size 2–3 mm) inserted into the cubic phantom. Phantom made up of Styrofoam, was scanned with the help of 16 slice Toshiba CT scanner where each slice was of 1 mm thickness and HU level set to −1000. A radio-opaque contrast medium was rubbed on the phantom to visualize the scanner images. Once the iso-center had been marked on a phantom with the help of in-room positioning laser and the fields (RT-LAT and AP) were applied on the contoured body of the phantom in Varian’s ARIA-11 Eclipse dosimeter software, the same position of the phantom was reproduced on Varian’s Linear Accelerator DHX. Known shifts of 3.0 to 30.0 mm from the marked iso-center were applied on the phantom by moving the couch in all six directions one by one. On each applied couch shift, an x-ray image of the phantom was acquired with the help of an MV portal imager of Linac in AP and RT-LAT direction. This image was superimposed with a reference image of phantom and shift accuracy calculated by ARIA-11 software was noted down. It turned out that irrespective of the position of the phantom on the couch, the calculated corrected shift and deviation from reference position was always between ± 1–2 mm which is the required accuracy for IGRT according to International Atomic Energy Agency (IAEA). This process was repeated 40 times and each time, the corrected shift came out to be ± 1–2 mm. We can conclude that our system is safe and accurate enough to perfectly position the actual patient for IGRT.

Introduction: To report the planning parameters, efficacy and toxicity of total body irradiation using volumetric modulated arc therapy (VMAT). Methods: From July 2019 till May 2021, nine patients treated with VMAT-based total body irradiation as a part of the myeloablative regimen for homologous stem cell transplant were evaluated. The CT acquisition, planning parameters, doses to target volume and critical structures were evaluated retrospectively. Results: Median age was 24 with median height 172 cm. Average Mean Lung dose was 9·5 Gy, mean dose to kidney was kidney dose 8·4 Gy, planning target volume (PTV) 95% was 98 % and mean heterogeneity index of PTV was 1·2 all patients. Total fraction delivery time including setup was 3·1 h while beam on time was 23 min. Main toxicity observed was mucositis and fatigue, while no Grade 3 or more acute radiation toxicity was observed. Conclusion: At our institution, high dose TBI performed with multi-isocentric VMAT is now a standard procedure. Though it is cumbersome and time-consuming process but VMAT offers an advantage of increased dose homogeneity in the target volume with reduction in doses to critical organs especially lungs and kidneys in comparison to standard source to skin distance technique, longer follow-up time is necessary to evaluate our method and long-term toxicity.

To report the efficacy and toxicity of neoadjuvant chemotherapy (NACT) before standard concurrent chemo radiation (CCRT) in locally advanced carcinoma of cervix. Methods: Between January 2007 and December 2016, 75 patients with locally advanced cervical cancer treated with neoadjuvant chemotherapy comprising carboplatin area under curve (AUC) 5 and Paclitaxel 175 mg/m 2 followed by chemo radiotherapy 45-59 Gy in 25-28 fractions with concurrent cisplatin and high dose rate (HDR) brachytherapy at our institution were analyzed. Clinical response rate, disease free survival, overall survival and toxicity was evaluated and documented using European organization for research and treatment of cancer (EORTC) criteria. Results: Baseline characteristics were median age at diagnosis 48 years; 86% squamous, and 14% adenocarcinoma histology; The international Federation of Gynecology and Obstetrics (FIGO) stage IB2-IIB (47%), III-IVA (53%). 64% had nodes involved and 84% had primary more than 4 cm in diameter. Complete or partial response rate was (95%) post-NACT and 92% (95% CI: 71-94) post-CRT. The median follow-up was 39.1 months. Overall and progression-free survivals at 4 years were 77% and 80% respectively. Grade ¾ hematological toxicities were 7% during NACT (11% hematological, 9% non-hematological) and 8% during CRT. The most common non hematological toxicity was diarrhea in 10%. The delayed toxicities at 24 months or later after CRT completion were rectal (11%), bladder (3%), and vaginal (28%). Conclusion: Neoadjuvant chemotherapy in locally advanced cervical cancer offers a favorable paradigm as reflected by acceptable toxicity and is associated with a high response rate in locally advanced cervical cancer. However, further randomized clinical trials are needed to support this evidence.