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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]

Objective To prospectively analyze the effect of three-dimensional chemoradiation on the bone mineral density of pelvic bones and its association with low back pain and disability in patients with locally advanced cervical cancer. Methods In biopsy proven locally advanced cervical cancer patients, bone mineral density and T scores for lumbar vertebrae 5, dorsal thoracic vertebrae 12, and T scores for the femoral neck were analyzed. Low back pain was scored using the visual analog scale while disability scoring was done using the Oswestry low back pain disability scale. Furthermore, a subgroup analysis for patients (classified according to menopausal status) was performed. Results In total, 106 patients were analyzed. A statistically significant decline in mean bone mineral density was observed at all three sites (vertebrae 5 and 12, and the femoral neck) post-chemoradiation therapy compared with pretreatment bone mineral density (0.671 vs 0.828, -2.083 vs -1.531, -2.503 vs -1.626; all p<0.001). Similarly, in subgroup analyses, at all three sites, pre-menopausal patients showed a statistically significant association (0.876 vs 0.697, -1.203 vs -0.2.761, -1.403 vs -2.232; all p<0.001) while a non-significant association was observed for post-menopausal patients at vertebrae 12 (-1.707 vs -1.719; p=0.09) with a statistically significant association at vertebrae 5 and the femoral neck (0.803 vs 0.656, -1.746 vs -2.648; p<0.01). Although statistically significant low back pain and disability scores were observed overall and irrespective of menopausal status, no correlation between bone mineral density and low back pain and disability was observed. Conclusion Pelvic bone mineral density decreases significantly after chemoradiation, irrespective of menopausal status. However, no correlation with low back pain and disability was observed. Pelvic bone mineral density analysis should be considered before chemoradiation in cervical cancer. [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]

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]

Objective: Conformal radiation is the standard of care in treatment of glioblastoma. Although co‐registration of magnetic resonance imaging (MRI) with early contrast enhanced computed tomography (CECT) is recommended for target delineation by consensus guidelines, ground realities in developing countries often result in availability of less‐than‐ideal MR sequences for treatment planning. Purpose of this study is to analyze the impact of incorporation of delayed‐CECT sequences for radiation planning in glioblastomas, as an adjunct or alternative to MRI. Methods: Case records of all patients of glioblastoma treated at our center between 2011 and 2014 were retrospectively evaluated. Gross treatment volumes were delineated on T1 contrast MRI (m‐GTV), early CECT (e‐GTV) and delayed CECT (d‐GTV); volumetric comparisons were made using repeated measures analysis of variance and pair‐wise analysis. Results: Although 96% of registered patients underwent postoperative MRI, only 38% of them had desirable sequences suitable for co‐registration. Median duration between acquisition of postoperative MRI and surgery was 45 days (range, 33–60), whereas that between MRI and treatment‐planning CT was 5 days (range, 1–10). Statistically significant differences (P < 0.0001) were obtained between mean volumes of e‐GTV (41.20cc), d‐GTV (58.09cc) and m‐GTV (60.52cc). Although the mean GTV increased by 46% between early CECT and MRI, the difference was only 4% between delayed CECT and MRI. Conclusion: Delayed CECT is superior to early CECT for co‐registration with MRI for target delineation, especially when available MR sequences are less‐than‐ideal for treatment planning, and can be considered as the most appropriate adjunct as well as an alternative to MRI, compared to early CECT. [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]

There are no published data on the cost of cancer treatment for guiding reimbursement decisions in India. The present study was designed to estimate the cost of treating head and neck cancer (HNC) with the aim of determining package rates. The present study was undertaken in the Departments of Radiotherapy and Otolaryngology of a large tertiary care hospital in North India. Economic health system costs incurred were assessed using a bottom-up methodology. Data on all resources–capital or recurrent, incurred on the delivery of HNC treatment were collected from April 2014 to March 2015. Following the cost-of-illness approach, patients were interviewed to elicit out-of-pocket (OOP) expenditure. A total of INR 40,993,017 (USD 0.67 million) was spent on radiotherapy care for treating HNC during 1 year. Salaries constituted the major component (42.6%) of this cost, followed by equipment/furniture (29%), space rent (20.7%), overheads and consumables (7.7%). In addition, INR 47,191 (USD 773) per HNC patient was spent on the surgery. Furthermore, patients spent an average amount ranging from INR 12,575 (USD 206) to INR 65,257 (USD 1069) on the different treatment therapies. In terms of package rates, cobalt radiotherapy alone was the cheapest (INR 38,714, USD 634), while intensity modulated radiotherapy (IMRT) was most expensive (INR 192,914, USD 3161). The estimates from the present study could be used for developing package rates under various publicly financed health insurance schemes as well as for the planning for creation of new cancer centres. [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]

Introduction: In prostate cancer, higher radiation doses are often related to higher local control rates. However, the clinical effect of these higher doses on normal tissue toxicities is generally overlooked. We dosimetrically analyze sequential intensity modulated radiotherapy (IMRT) plans in high-risk prostate cancer patients and correlate them with acute and late normal tissue toxicities. Materials and Methods: Twenty‑five high‑risk prostate cancer patients were planned with three‑dimensional conformal radiotherapy to a dose of 50 Gy delivered in 25 fractions in 5 weeks, followed by seven‑field IMRT boost, to a dose of 24 Gy delivered in 12 fractions in 2.5 weeks, along with hormonal therapy. Acute and late toxicities were analyzed using Radiation Therapy Oncology Group toxicity criteria. Student’s t-test was used for correlating doses received by normal tissues with toxicity grade. Five-year disease-free survival (DFS) and biochemical relapse-free survival (RFS) were evaluated using Kaplan–Meier analysis. Results: Median follow-up of patients was 65 months. Of 25 patients, two developed acute Grade 2 rectal toxicity. Only 1 patient developed acute Grade 2 bladder toxicity. Late Grade 2 and 3 rectal toxicity was seen in 2 and 1 patient, respectively. Late Grade 2 and 3 bladder toxicity was seen in 1 patient each. Grade 2 or more acute rectal toxicity correlated significantly with rectal volume receiving >70 Gy (P = 0.04). The 5‑year DFS and biochemical RFS was 70.2% and 79.2%, respectively. One patient failed locally and seven failed at distant sites. Conclusion: Sequential IMRT with a dose of 74 Gy and maximum androgen blockade is well tolerated in high‑risk patients in Indian setup with adequate control rates. [ABSTRACT FROM AUTHOR]

Purpose: The quality of intensity-modulated radiotherapy (IMRT) highly depends on the choice of beam orientations and optimization algorithms used in the treatment planning. The present work reports dosimetric study of IMRT plans generated using preselected equiangular beam orientations (PSBO) and beam angle optimization (BAO) for the patients of prostate, head and neck, and esophagus carcinoma.Materials and Methods: The computed tomography (CT) datasets of 30 patients treated with IMRT for prostate, head and neck, and esophagus carcinoma were selected. Two IMRT plans were made for each patient. First plan was prepared for seven to nine fields PSBO in coplanar arrangement. The second plan was made using the BAO by a computerized algorithm compatible treatment planning system (TPS). The dose-volume histograms (DVHs) of PSBO and BAO plans were compared for all the patients. The treatment plans were compared using the parameters delivered monitor units (MUs), doses delivered to organs at risk (OARs), target coverage (conformity index (CI)), homogeneity index (HI), and quality index (QI).Results: DVHs generated showed that OARs receive almost identical or slightly better doses in case of BAO as compared to PSBO. CI, HI, and QI values were almost same for two plans. However, we have noticed significant reduction in MUs for all the plans generated using BAO.Conclusions: It is concluded that BAO provides superior plan with respect to MUs and should be used whenever possible in IMRT planning. [ABSTRACT FROM AUTHOR]

Purpose: To determine outcomes of interstitial high-dose-rate brachytherapy (HDR-BT) in patients with early stage oral tongue cancer. Material and methods: Ninety-two patients with stage I and II oral tongue cancer were treated with HDR-BT between 1999 and 2014: brachytherapy alone = 62 (67.4%), and combination of external beam radiotherapy (EBRT) and brachytherapy = 30 (32.6%). Median follow-up was 53.5 months. Patterns of failure, overall survival (OS), disease-free survival (DFS), local control rates (LCR), and nodal control rates (NCR) were determined. Results: 5-year OS, DFS, LCR, and NCR were 73.2%, 58.2%, 64.2%, and 83.8%, respectively. In total, 43 patients (46.7%) failed treatment: isolated local failures = 28 (30.4%), isolated nodal failures = 8 (8.7%), both local and regional failures = 7 (7.6%). While in T1 stage, 5 year LCR were significantly higher in brachytherapy alone group compared to combined EBRT and brachytherapy group (81.7% vs. 62.5%, p = 0.04), the isolated nodal failure rates were not significantly different among the two groups. For T2 stage, NCR were higher in combined EBRT and brachytherapy group compared to brachytherapy alone (92.9% vs. 74.3%). Acute mucositis (grade > 2) was seen more in brachytherapy alone group compared to the combined modality group (87% vs. 66%), and this correlated significantly with the higher biological equivalent dose (BED) in the brachytherapy alone group. Conclusions: Our study recommends treating patients with brachytherapy alone in T1 stage, and demonstrates the need for addressing nodal region either by neck dissection or nodal irradiation in T2 stage patients. Also, the study highlights the need for dose escalation (from the doses used in the study) in both T1 and T2 stage tumors when using interstitial brachytherapy either as sole modality or as a boost. [ABSTRACT FROM AUTHOR]

Purpose: To recognize neuropathic pain as a complication of high-dose-rate (HDR) interstitial brachytherapy of oral tongue and to evaluate the possible causes of neuropathy. Material and methods: Twenty one patients who underwent interstitial brachytherapy for early cancer of oral tongue were evaluated. The patients either underwent primary brachytherapy (42-48 Gy at 3-4 Gy/fraction) or a boost (18-24 Gy at 3 Gy/fraction) after external radiation to 40 Gy. Lingual nerve was the nerve concerned and the sublingual space (SLS) was contoured as its surrogate. Dosimetric parameters were correlated with onset of pain. Results: Ten patients out of 21 (47.61%) developed painful neuropathy. Five patients of six (5/6) who underwent primary brachytherapy developed neuropathy. Five out of 15 (5/15) patients who underwent brachytherapy as a boost developed neuropathy. The patients who underwent primary brachytherapy were ten times more likely to develop neuropathy. Among the patients receiving boost treatment, the equivalent dose at 2 Gy/fraction (EQD2) to 2 cc of SLS was higher (39.25 Gy) in the patients who developed pain compared to those without pain (10.29 Gy). Conclusions: This is the first report to recognize neuropathic pain as a complication of HDR brachytherapy of oral tongue. Patients undergoing primary brachytherapy were more likely to develop pain. Among other factors like dose to SLS, number of catheters, size of the primary tumor, and the dose rate, only dose to 2 cc of the SLS correlated with onset of pain. The SLS (containing the lingual nerve) may be considered an organ at risk to prevent the occurrence of this complication. [ABSTRACT FROM AUTHOR]

Background: Treatment of periampullary cancer involves Whipple surgery, followed by adjuvant radiotherapy and chemotherapy. Postoperative radiotherapy is particularly useful in managing high-risk patients (tumors involving the pancreas, poorly differentiated histology, involved lymph nodes and positive margins). Here, we review our results of treatment of 84 patients treated by surgery and adjuvant radiotherapy and chemotherapy. Material and Methods: A retrospective analysis of 84 patients of periampullary cancers treated in our department between January 2007 and December 2012 was carried out. All patients underwent Whipples surgery followed by postoperative radiotherapy 45-50 Gy/25-28 number in those presenting with high-risk features. Radiotherapy was delivered using three-dimensional conformal technique with 6 MV photons using three field treatment plans. Chemotherapy was given for 6 cycles using gemcitabine and oxaliplatin regimen repeated 2 weekly. Results: Eighty four postoperative patients with high-risk features were available for the final analysis. There were 69 males and 15 female patients. There were 34.5% stage I, 57.1% stage II and 8.3% stage III patients. At end of adjuvant treatment with radiotherapy and chemotherapy 70% patients had a complete response, 7.5% had residual disease, 15% showed progressive disease, 5% were dead and 2.5% defaulted the treatment. The mean number of chemotherapy cycles received was 2.6. At 1 year follow-up the probability of disease free survival was 80% for node-negative patients versus 73% for node-positive disease (P = 0.27). Patients with stage up to IIA had a 1 year disease free survival of 83% versus 40% for patients with stage beyond IIA (P = 0.024). Conclusions: Our results showed a trend favoring lymph node negative status with disease free survival. With computed tomography based planning, adequate delineation of draining nodes is possible, and radiation toxicity has significantly decreased. Adequate coverage of nodal basins during radiotherapy planning is important, and stage of the disease seems to be an important prognostic factor. [ABSTRACT FROM AUTHOR]

Background. Quantifying the interfraction dose variations in the organs at risk (OAR) in HDR intracavitary brachytherapy (HDR ICBT). Methods. Rectum and bladder were contoured in 44 patients of cervical carcinoma on CT after each fraction of HDR ICBT (9 Gy/2 fractions). Interfraction dose variations (VARact) were calculated. Rigid image registration of consecutive fraction images allowed quantification of the hypothetical variation in dose (VARhypo) arising exclusively due to changes in applicator placement and geometry. VARhypo was regressed against the VARact to find out to what extent the applicator variation could explain the VARact in the OAR. The rest of the variation was assumed to be due to organ deformation. Results. The VARact in the dose to 2 cc of bladder and rectum were 1.46 and 1.16 Gy, respectively. Increased dose was seen in 16 and 23 patients in the subsequent fraction for bladder and rectum, respectively. Doses to OAR would have exceeded constraints in 16% patients if second fraction was not imaged. VARhypo explained 19% and 47% of the VARact observed for the bladder and rectum respectively. Conclusions. Significant interfraction variations in OAR doses can occur in HDR ICBT. Organ deformations are mostly responsible for this variation. [ABSTRACT FROM AUTHOR]

Introduction: Dosimetric study to compare high dose rate (HDR) vaginal vault ovoid brachytherapy plan versus intensity-modulated radiation therapy (IMRT) boost plan for doses delivered to target volume and organs at risk (OAR) in postoperative patients of cervical carcinoma following whole pelvic radiotherapy (WPRT). Materials and Methods: Fifteen postoperative patients of cervical carcinoma suitable for vaginal ovoid brachytherapy following WPRT of 46 Gy/23 fractions/4.5 weeks were included. All were treated with brachytherapy (two sessions of 8.5 Gy each). The equivalent dose for IMRT was calculated by computing biologically effective dose of brachytherapy by linear quadratic model. Dose of brachytherapy (two sessions of 8.5 Gy) was equivalent to IMRT dose of 26 Gy/13 fractions. Doses to target volume and OAR were compared between HDR and IMRT plans. Results: Target volume was well covered with both HDR and IMRT plans, but dose with brachytherapy was much higher (P < 0.05). Mean doses, doses to 0.1, 1, 2, and 5cc, 1/3rd, 1/2, and 2/3rd volume of bladder and rectum were significantly lower with HDR plans. Conclusion: In postoperative patients of cervical carcinoma, HDR brachytherapy following WPRT appears to be better than IMRT for tumor coverage and reducing dose to critical organs. [ABSTRACT FROM AUTHOR]

The purpose of this study is to compare Lyman-Kutcher-Burman (LKB) model versus Niemierko model for normal tissue complication probability (NTCP) calculation and Niemierko model versus Poisson-based model for tumor control probability (TCP) calculation in the ranking of different treatment plans for a patient undergoing radiotherapy. The standard normal tissue tolerance data were used to test the NTCP models. LKB model can reproduce the same complication probability data of normal tissue response on radiation, whereas Niemierko model cannot reproduce the same complication probability. Both Poisson-based and Niemierko models equally reproduce the same standard TCP data in testing of TCP. In case of clinical data generated from treatment planning system, NTCP calculated using LKB model was found to be different from that calculated using Niemierko model. When the fractionation effect was considered in LKB model, the calculated values of NTCPs were different but comparable with those of Niemierko model. In case of TCP calculation using these models, Poisson-based model calculated marginally higher control probability as compared to Niemierko model. [ABSTRACT FROM AUTHOR]

Context: The increasing popularity of intensity-modulated radiotherapy (IMRT) stems from its ability to generate a more conformal plan than hitherto possible with conventional planning. As a result, IMRT is in widespread use across diverse indications. However, the inherent nature of IMRT delivery makes it monitor unit inefficient and leads to increased normal tissue integral dose. This in turn may result in an increased risk of radiation-induced second malignancies. Aim: To calculate the risk of second malignancy post-IMRT. Settings and Design: Observational study in a tertiary care institute. Materials and Methods: Eighteen previously untreated patients with head and neck cancers (n = 10) and prostate cancer (n = 8) were selected. In these patients, selected infield organs around the planning target volume were contoured, viz. brain and thyroid in patients with head and neck cancer and bladder, rectum and small intestine in patients with carcinoma prostate. The estimates of radiation-induced malignancies in these organs and the whole of the body were derived using the concept of Organ Equivalent Dose. Statistical Analysis Used: Descriptive statistics (SPSS version 12). Results: The modal estimated incidence of radiation-induced malignancies was 129.87, 1.4, 0.10, 3.42, 7.789 and 129.85 per 10,000 person-years for the brain, thyroid, bladder, rectum, small intestine and whole body respectively. Conclusions: The estimated risk of radiation-induced malignancies in the thyroid and rectum was similar to the available literature, while the risk for bladder carcinomas was lower than that reported. However, the calculated risk of radiation-induced tumors of the brain was more than that reported with conventional radiation therapy. We propose that estimation of the risk of radiation-induced malignancies should be a part of the plan evaluation process and special care should be taken before using this modality in young patients with benign tumors in the head and neck region. [ABSTRACT FROM AUTHOR]

Aim: Compare the planning target volume (PTV) coverage in three different shielding techniques in cranial irradiation. Settings and Design: Tertiary care center, prospective study. Materials and Methods: The whole brain and meninges were contoured in ten planning CT scans, and expanded by 5 mm for the PTV. Shielding was designed using the French Society of Pediatric Oncology (SFOP) guidelines (SFOP plan), in-house recommendation (with 1 cm margin from the orbital roof and sphenoid wing) on a igitally Reconstructed Radiograph (DRR) and a third plan was generated using a 3D conformal radiation technique (3DCRT). The coverage of the PTV was noted using the isodose covering 95% of the PTV(D95), minimum dose within the PTV(Dmin), and maximum dose within the PTV(Dmax). The location of PTV not covered by the 95% isodose curve was noted. The median dose and maximum dose (Dmax) to both eyes and maximum dose Dmax for the lens were noted. Statistical Analysis: General linear model method repeated the measure of analysis of variance test (ANOVA). Results: PTV coverage was significantly poorer in the SFOP and in-house plans as compared to 3DCRT plan (P=0.04). Median volume of PTV not covered by 95% isodose curve was 4.18 cc, 1.01 cc, and 0 cc in SFOP, in-house, and 3DCRT plan, respectively. Conclusions: In the absence of volumetric planning techniques, SFOP guidelines lead to inadequate coverage and the in-house method is recommended. [ABSTRACT FROM AUTHOR]

2D array of ionization chambers can be used for both absolute and relative dose verification of patient-specific intensity-modulated radiotherapy (IMRT) quality assurance. After an analysis of the dose linearity and spatial resolution of this 2D array (I'mRT MatriXX), the signal sampling time of 200 ms was selected for data acquisition. Multiple-sequence acquisitions at the nearest 4 positions with the shift of half of the distance between the centers of two adjacent ion chambers increase the spatial resolution up to four times when used with this I'mRT MatriXX. IMRT verification of head-and-neck case, which requires a large area for dosimetric verification, can be done with limited size of 24x24 cm², depending on the user requirements. It is found that the convolution method can also be used to improve the IMRT dose verification with the same parameters of the passing criteria significantly, viz., up to 99.87% agreement, by smoothening the treatment planning system profile. [ABSTRACT FROM AUTHOR]

Background: Intensity-modulated radiotherapy using simultaneous integrated boost (SIB-IMRT) is an attractive method for the treatment of head and neck cancers with sparing of the salivary function. Aims: To assess the feasibility, toxicity, and tumor control using SIB-IMRT in locally advanced head and neck cancers in the Indian setting. Settings and Design: The study was conducted in a regional cancer center in northern India. A review of the treatment result of the first 20 patients is presented. Methods and Materials: SIB-IMRT was planned for 20 patients—14 patients were treated with the SIB-72 schedule delivering a dose of 72 Gy, 66 Gy, and 57 Gy to the PTVGTV, PTVCTV1, and PTVCTV2 in 33 fractions. Six patients were treated with the SIB-66 schedule delivering 66 Gy, 60 Gy, and 54 Gy to the above-mentioned volumes in 30 fractions. Patients were monitored for toxicity using the CTCAE v 3.0 criteria. Descriptive analysis of toxicity and actuarial estimates of the loco-regional control and survival are presented. Results: Grade III mucositis was seen in 65% patients. None of the patients had Grade III dermatitis. The projected 2-year overall survival was 95%. Conclusion: SIB-IMRT schedules evaluated were found to be safe and effective and are being subjected to further prospective studies. [ABSTRACT FROM AUTHOR]

Purpose: To derive and validate an index to correlate the bladder dose with the catheter balloon dose using limited computed tomography (CT) slices. Materials and Methods: Applicator geometry reconstructed from orthogonal radiographs were back-projected on CT images of the same patients for anatomy-based dosimetric evaluation. The correlation indices derived using power function of the catheter balloon dose and the bladder volume dose were validated in 31 patients with cervical cancer. Results: There was significant correlation between International Commission on Radiation Units (ICRU)-38 balloon reference dose (Dr) and the dose received by 25% bladder volume (D25) (P < 0.0001). Significant correlation was also found between the reference dose of mid-balloon point (Drm) and the dose to D25 (P < 0.0001). Average percentage difference [100 x (observed index - expected index) / expected index] of observed value of I'25 (index for the dose to D25 bladder with respect to mid-balloon reference point) from that of expected value was 0.52%, when the index was modeled with reference dose alone. Similarly the average percentage difference for I'10cc (index for the dose to 10 cc volume of bladder with respect to mid balloon point) was 0.84%. When this index was modeled with absolute bladder volume and reference dose, standard deviation of the percentage difference between observed and expected index for Drm reduced by approximately 2% when compared to Dr. Conclusion: For clinical applications, correlation index modeled with reference dose and volume predicts dose to absolute volume of bladder. Correlation index modeled with reference dose gives a good estimate of dose to relative bladder volume. From our study, we found Drm to be a better indicator of bladder dose than Dr. [ABSTRACT FROM AUTHOR]