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Introduction: Total skin electron beam therapy, commonly known as TSET, is a good choice of treatment for patients suffering from mycosis fungoides. The aim of this study was to introduce a new approach to the beam profile measurement using diodes and to calculate the monitor units required for the TSET treatment by the use of a simple setup of output measurement. Dosimetric measurements required for the treatment were taken to establish the Stanford technique in the department, and the measured data was compared with the published data. Materials and Methods: High-energy Linear Accelerator Clinac-DHX, Varian medical system, Palo Alto, CA, was commissioned for TSET. The output of the machine was measured by the use of a Parallel-Plate Chamber (PPC40) as per the TRS 398 recommendation. Diode dosimeters (EDD2 and EDD5) were used for beam profile measurements due to easy setup and to reduce the measurement time. Results: Homogeneous dose distribution within a field size of 80 cm x160 cm was observed with the variation of -5.0% on the horizontal axis and -5.4% on the vertical axis. The calculated monitor unit to deliver 200 cGy per fraction per field at the source to surface (SSD) of 416 cm was 489 MU. Conclusion: The technique described for the output measurements is simple and accurate. Results of the absorbed dose and MU measured were within good agreement compared to the published literature. [ABSTRACT FROM AUTHOR]

Introduction: Linear accelerator (LINAC) embedded with kV source-imager system is capable to do image-guided radiotherapy. The only disadvantage of cone-beam computed tomography image acquisition during treatment is the extra radiation dose to the patient. The aim of this study is to optimize the CBCT imaging doses likely to be received by the patient undergoing radiotherapy without affecting image quality. Material and Methods: The imaging dose to the patient was estimated on CTDI phantoms. The effect of additional filters of different materials (copper, brass, aluminum of thickness 0.1 mm each) was evaluated to find the optimized dose imaging technique. For the pelvis, a single imaging protocol available on the machine was used, whereas for the head and neck region, two protocols, high-quality head and standard-dose head were used. The image quality was assessed on CATPHAN-504 phantom using Owl CATPHAN® QA online tool. A new term "Image Assessment score" (IAS) was introduced to evaluate the image quality. Result: In the pelvis protocol, CBCT imaging doses with an additional 0.1-mm brass, copper, and aluminum filter were measured to be reduced by 7.1%, 4.7%, and 2.5%, respectively, whereas for high-quality head protocol, the dose reduction was 25.4% (with brass filter), 22% (with copper filter), and 3.1% (with aluminum filter). For the standard-dose head protocol, doses were reduced by 7.5%, 2.8%, and 2.1% with additional 0.1-mm brass copper and aluminum filters, respectively. Acceptable image quality was observed with all the filters. Conclusion: Although the reconstructed images were found somewhat noisier, they did not affect the purpose of imaging, that is, treatment position verification. It was observed that these extra filters further reduce the imaging dose without much affecting the image quality. [ABSTRACT FROM AUTHOR]

Introduction: Chemoradiation therapy (CRT) remains the treatment of choice for inoperable locally advanced esophageal cancer (LAEC). Several CRT regimens are existent in esophageal cancer, but definitive conclusions are lacking. We performed a pilot study to compare treatment outcome, survival, and toxicities in inoperable upper and middle third esophageal cancer patients undergoing CRT using either paclitaxel/carboplatin or cisplatin/5FU based regimen.Methods: Patients were randomised in two arms (arm A and arm B). In Arm A, taxane-based (Paclitaxel+carboplatin) and in arm B non-taxane-based (cisplatin+5FU) doublet chemotherapy drugs were given concurrently with external beam radiation therapy (EBRT). EBRT in two phases up to a total dose of 54 Gy/27#@2Gy/# was given. Response was subsequently assessed using Response evaluation criteria in solid tumors (RECIST v1.1) and toxicities utilizing Common Terminology Criteria for Adverse Events (CTCAE v 4.0).Result: The overall response rate (ORR) in the taxane-based group was higher than the non-taxane-based group, but was not significantly different (p=0.851). Regarding hematological toxicities, anaemia and reduced cell counts were more in the taxane group compared to the non-taxane group while non-hematological toxicities were comparable. Similarly, better survival with late toxicities were seen with taxane-based arm when compared to non-taxane-based arm, though it was not statistically significant.Conclusion: Our pilot analysis highlights the fact that paclitaxel/carboplatin CRT shows better response, survival, and comparable toxicities when compared to cisplatin/5FU, though statistically nonsignificant. Further randomised prospective trials with large sample size are warranted. [ABSTRACT FROM AUTHOR]

Background: A purpose of the study was to investigate the dosimetric impact of contrast media on dose calculation using average 4D contrast-enhanced computed tomography (4D-CECT) and delayed 4D-CT (d4D-CT) images caused by CT simulation contrast agents for stereotactic body radiation therapy (SBRT) of liver cases. Materials and methods: Fifteen patients of liver SBRT treated using the volumetric modulated arc therapy (VMAT) technique were selected retrospectively. 4D-CECT, and d4D-CT were acquired with the Anzai gating system and GE CT. For all patients, gross target volume (GTV) was contoured on the ten phases after rigid registration of both the contrast and delayed scans and merged to generate internal target volume (ITV) on average CT images. Region of interest (ROI) was drawn on contrast images and then copied to the delayed images after rigid registration of two average CT datasets. The treatment plans were generated for contrast enhanced average CT, delayed average CT and contrast enhanced average CT with electron density of the heart overridden. Results: No significant dosimetric difference was observed in plans parameters (mean HU value of the liver, total monitor units, total control points, degree of modulation and average segment area) except mean HU value of the aorta amongst the three arms. All the OARs were evaluated and resulted in statistically insignificant variation (p > 0.05) using one way ANOVA analysis. Conclusions: Contrast enhanced 4D-CT is advantageous in accurate delineation of tumors and assessing accurate ITV. The treatment plans generated on average 4D-CECT and average d4D-CT have a clinically insignificant effect on dosimetric parameters. [ABSTRACT FROM AUTHOR]

Background Though conformal partial-brain irradiation is the standard adjuvant treatment for glioblastoma, there is no consensus regarding the optimal volume that needs to be irradiated. European Organisation for Research and Treatment of Cancer (EORTC) and The University of Texas MD Anderson Cancer Center (MDACC) guidelines differ from the Radiation Therapy Oncology Group (RTOG) in their approach toward peritumoral edema, whereas RTOG and MDACC guidelines differ from EORTC in the concept of boost phase. A scarcity of randomized comparisons has resulted in remarkable variance in practice among institutions. Methods Fifty glioblastoma patients were randomized to receive adjuvant radiotherapy using RTOG or MDACC protocols. Apart from dosimetric and volumetric analysis, acute toxicities, recurrence patterns, progression-free survival (PFS), overall survival (OS), and quality of life (QoL) were compared using appropriate statistical tests. Results Both groups were comparable with respect to demographic characteristics. Dosimetric analysis revealed significantly lower boost-phase planning treatment volumes and V60 Gy in the MDACC arm (chi-squared, P =.001 and.013, respectively). No significant differences were observed in doses with respect to organs at risk, acute toxicity, or recurrence patterns (chi-squared, P >.05). On the log-rank test, median PFS (8.8 months vs 6.1 months, P =.043) and OS (17 months vs 12 months, P =.015) were statistically superior in the MDACC group. Age, extent of resection, and proportion of whole brain receiving prescription dose were associated with improved PFS and OS on regression analysis. QoL of patients was significantly better in the MDACC group in all domains except cognitive, as assessed with the EORTC Quality of Life Questionnaire (QLQ-C30) and Brain Cancer Module (QLQ-BN20) (general linear model, P <.05). Conclusions Use of limited-margin MDACC protocol can potentially improve survival outcomes apart from QoL of glioblastoma patients, as compared with the RTOG protocol. [ABSTRACT FROM AUTHOR]

Gamma knife radiosurgery (GKRS) has emerged as a suitable primary treatment option for confined cavernous sinus tumors (CSTs) and residual/recurrent benign tumors extending from the surrounding neighborhood. The aim of this review was to further investigate the safety and efficacy of single-fraction GKRS for primary confined CSTs (hemangioma, meningioma, and schwannoma). This was a retrospective analysis of 16 patients of CSTs, primarily treated with GKRS between 2009 and 2017. The patients underwent follow-up clinical and radiological evaluation at a regular interval. Data on clinical and imaging parameters were analyzed. The published literature on GKRS for CSTs was reviewed. There were total 16 patients (eight meningiomas, seven hemangiomas, and one schwannoma). Patients presented with a headache (56.3%), ptosis (50%), and/or restricted extraocular movements (50%). There was 46.6% tumor volume (TV) reduction after single-fraction GKRS. Hemangiomas showed best TV reduction (64% reduction at > 3-year follow-up) followed by schwannoma (41.5%) and meningioma (25.4%). 56.3% of patients developed transient hypoesthesia in trigeminal nerve distribution. 44.4% of patients became completely pain-free. Among cranial nerves, the superior division of the oculomotor nerve showed best outcome (ptosis 62.5%) followed by an improved range of EOM. There was no adverse event in the form of new-onset deficit, vascular complication, or malignant transformation except for one out of the field failures. Among available treatment options, GKRS is the most suitable option by virtue of its minimally invasive nature, optimal long-term tumor control, improvement in cranial neuropathies, cost-effectiveness, favorable risk-benefit ratio, and minimal long-term complications. [ABSTRACT FROM AUTHOR]

Aim: The aim of the present study was to access the need of daily cone-beam computed tomography (CBCT) and the requirement of in-house protocols of image acquisition frequency to reduce unnecessary exposure to the patients undergoing radiotherapy treatment.Materials and Methods: The dose delivered during CBCT procedure (On-Board Imager, Trilogy, Varian medical system, Inc., Palo Alto, California) was assessed for pelvic and head and neck region. For dose estimation, cylindrical polymethyl methacrylate phantoms of 15 cm length, 16 cm, and 32 cm diameter were used to simulate the patient's head and neck and pelvic region thickness, respectively. More than 10 cm scatterer was added on either end of this phantom. Calibrated Ionization chamber DCT10 LEMO SN 1685 iba, dosimetry, Germany (10 cm active length) was used to measure the dose Index. The doses known as cone-beam dose index (CBDI100) were estimated for all the scanning protocols (kV and mAs setting) available on the machine. In this study, image acquisition frequency to correct the setup error was optimized. In-house protocol for image acquisition frequency during treatment has been suggested to reduce the dose. It was based on the principle of as low as reasonable achievable.Results: Optimized dose protocol observed was the "standard dose head" for which the CBDI100 was 2.43 mGy. Whereas for pelvic imaging, single protocol of 125 kV, 80 mA was available by which a dose of 7.61 mGy is likely to be received by the patient during scan. Maximum shift of 6 mm in lateral direction was observed to the patient of Pelvis region and 5 mm was observed in the longitudinal direction for the H and N patients. Angular shift measured in patient position was 3.8° and 3.1° for H and N and pelvic region, respectively.Conclusion: Three consecutive-day CBCT-imaging at the beginning of the treatment followed by once weekly CBCT and two-dimensional (2D) imaging in remaining days of treatment can be an optimized way of imaging for the patient having malignancy in the region of pelvic and abdomen. For H and N, once in a week, CBCT with standard dose head protocol, followed by 2D-imaging in remaining days can be an optimized way of imaging. [ABSTRACT FROM AUTHOR]

Purpose: This trial studies the feasibility and potential utility of stereotactic body radiation therapy in patients with unresectable liver metastasis.Aims: (1) The aim of this study is to assess the local response of the liver lesions poststereotactic body radiation therapy regarding number and size of lesions and (2) to evaluate the toxicity to organ (s) at risk.Materials and Methods: A total of 15 patients were enrolled in this study from November 2014 to October 2015. The inclusion criteria for this study were patients having 1-3 liver metastasis from any solid tumor except germ cell tumor or lymphoma with no evidence of progressive disease (PD) outside the liver. A planning four dimensional-computed tomography (CT) scan was taken. Planning target volume was generated by giving margin of 5 mm. Dose prescribed was 36 Gy in 3#. Response was defined by CT abdomen done at 3 and 6 months poststereotactic body radiation therapy as per RECIST guideline (v1.1).Results: At 3 months poststereotactic body radiation therapy, five patients had partial response, five patients had stable disease, and five patients had PD as per RECIST criteria. Out of 20 assessable lesions, 16 were controlled at 3 months poststereotactic body radiation therapy. The actuarial local control rate was 86% at 3 months and 77% at 6 months poststereotactic body radiation therapy. The median progression free survival was 7 months. Two patients experienced Grade 2 gastric toxicity and one patient experienced Grade 2 small bowel toxicity. No cases of radiation-induced liver disease were observed.Conclusions: This trial examines the feasibility of stereotactic body radiotherapy to liver metastasis in the Indian scenario. It shows excellent tolerability and is a safe therapeutic option for inoperable patients, showing good local control. [ABSTRACT FROM AUTHOR]

Introduction: Three-dimensional (3D) treatment planning of patient undergoing radiotherapy uses complex and meticulous computational algorithms. These algorithms use 3D voxel data of the patient to calculate the radiation dose distribution and display it over the CT image dataset for treatment plan evaluation. Aims and Objective: The purpose of the present study is the development and implementation of radiobiological evaluation of the radiotherapy treatment plan incorporating the tissue-specific radiobiological parameters. Material and Method: An indigenous program was written in MATLAB® software (version 2011b of Mathworks Inc.) to extract the patient treatment plan data from DICOM-RT files which are exported from the treatment planning system. CT-, Structures- and Dose-Cube matrices are reconstructed from the exported patient plan data. BED and EQD2 based dose volume histograms (DVHs), colorwash and iso-effective dose curves were generated from the physical Dose-Cube using the linear-quadratic (LQ) formalism and tissue-specific radiobiological parameters (α/β). Results and Conclusion: BED-and EQD2-colorwash and iso-effective curves along with BED and EQD2 dose volume histograms provide superior radiobiological information as compared to those of physical doses. This study provides supplementary recipes of radiobiological doses along with the physical doses which are useful for the evaluation of complex radiotherapy treatment plan of the patients. [ABSTRACT FROM AUTHOR]

Background: To evaluate the feasibility, safety and efficacy of dose fractionated gamma knife radiosurgery (DFGKRS) on a daily schedule beyond the linear quadratic (LQ) model, for large volume arteriovenous malformations (AVMs).Material and Methods: Between 2012-16, 14 patients of large AVMs (median volume 26.5 cc) unsuitable for surgery or embolization were treated in 2-3 of DFGKRS sessions. The Leksell G frame was kept in situ during the whole procedure. 86% (n = 12) patients had radiologic evidence of bleed, and 43% (n = 6) had presented with a history of seizures. 57% (n = 8) patients received a daily treatment for 3 days and 43% (n = 6) were on an alternate day (2 fractions) regimen. The marginal dose was split into 2 or 3 fractions of the ideal prescription dose of a single fraction of 23-25 Gy.Results: The median follow up period was 35.6 months (8-57 months). In the three-fraction scheme, the marginal dose ranged from 8.9-11.5 Gy, while in the two-fraction scheme, the marginal dose ranged from 11.3-15 Gy at 50% per fraction. Headache (43%, n = 6) was the most common early postoperative complication, which was controlled with short course steroids. Follow up evaluation of at least three years was achieved in seven patients, who have shown complete nidus obliteration in 43% patients while the obliteration has been in the range of 50-99% in rest of the patients. Overall, there was a 67.8% reduction in the AVM volume at 3 years. Nidus obliteration at 3 years showed a significant rank order correlation with the cumulative prescription dose (p 0.95, P value 0.01), with attainment of near-total (more than 95%) obliteration rates beyond 29 Gy of the cumulative prescription dose. No patient receiving a cumulative prescription dose of less than 31 Gy had any severe adverse reaction. In co-variate adjusted ordinal regression, only the cumulative prescription dose had a significant correlation with common terminology criteria for adverse events (CTCAE) severity (P value 0.04), independent of age, AVM volume, number of fractions and volume of brain receiving atleast 8 Gy of radiation.Conclusion: DFGKRS is feasible for large AVMs with a fair nidus obliteration rate and acceptable toxicity. Cumulative prescription dose seems to be the most significant independent predictor for outcome following DFGKRS with 29-30 Gy resulting in a fair nidus obliteration with least adverse events. [ABSTRACT FROM AUTHOR]