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Introduction: Head and Neck tumors are mainly treated with concurrent chemoradiation. Treatment delivery with Megavoltage beam has the advantage of skin sparing effect but still skin reactions have been a major side effect since 2D era. Initially these reactions were due to the delivery with bilateral opposed portals but with advent of IMRT/ VMAT, it has been possible to escalate the tumor dose with the need of strict immobilization with thermoplastic mask. This thermoplastic mask may have a bolus effect and can result in increase in surface dose resulting in skin reactions. The aim of this study was to evaluate if any bolus effect of thermoplastic mask exists. Materials and Methods: A total of 15 patients of histologically proven carcinoma oropharynx and hypopharynx were taken. Patients were scanned for planning CT with thermoplastic mask. Another scan was taken in the same position but without thermoplastic mask. Same contouring and planning were done on both the scans. Plans were made and ascertained that all OAR’s and target volumes should get similar doses. Skin contoured on both the scans was evaluated for the dose received. Results: Mean dose received by skin in patients with thermoplastic mask was 48.15 GY while Mean dose received by skin in patients without thermoplastic mask was 43.18 GY. A paired t-test was applied on the dataset which revealed a statistically significant difference between the skin doses with and without mask with a p value of < 0.05. Conclusion: Increase in skin dose can be attributed of the bolus effect of thermoplastic mask. This bolus effect should be considered once high dose to skin is observed during planning or patient develops skin reaction.

Background: In head and neck squamous cell carcinomas (HNSCC), residual disease, loco regional recurrence or development of second primary are causes of treatment failure. A combination of either surgery or chemotherapy or radiotherapy is used. The aim of this study was to evaluate recurrent/ relapsed HNSCC who were treated with re-irradiation, its toxicities and survival analysis. Materials and Methods: 72 patients were analysed retrospectively who had undergone re-irradiation at our institute. All patients were histologically proven cases of recurrent/relapsed HNSCC. Treatment was done using conformal radiotherapy techniques like IMRT or IGRT technique. Results: Patients who had recurrent disease and second primary were 38 (52.8%) and 34 (47.2%) respectively. The time interval between radiotherapy treatments ranged from 7 months to 25 years. Salvage surgery preceded radiotherapy in 16 (22.2%) patients and 56 patients (78.8%) underwent radical radiotherapy. The PTV volume ranged from 15.6 to 672.2 cc (median: 117 cc) and median dose was 54Gy. Mucositis and skin reactions were associated in patients with larger PTV volumes and lower time interval between the radiation treatments. The median DFS and OS was 13 months and 29 months respectively. OS at 1 year and 2 years was 58.3% and 36.1%. Patients who received radiation dose of >54Gy and who had >24 months interval between the radiation treatments fared better. Conclusions: Treatment approaches have to be personalized in cases of recurrent HNSCC. For re-irradiation in HNSCC we found better outcomes when there is adequate time period (> 24 months) between the radiation treatments and with dose > 54Gy.

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Objectives: Image-guided radiotherapy maximizes therapeutic index of brain irradiation by reducing setup errors during treatment. The aim of study was to analyze setup errors in the radiation treatment of glioblastoma multiforme and if decrease in planning target volume (PTV), margin is feasible using daily cone beam CT (CBCT) and 6D couch correction. Materials and Methods: Twenty-one patients (630 fractions of radiotherapy) were studied in which corrections were made in 6° of freedom. We determined setup errors, impact of setup errors of initial three fractions CBCT versus rest of the treatment with daily CBCT, and mean difference in setup errors with or without application of 6D couch and volumetric benefit of reduction of PTV margin from 0.5 cm to 0.3 cm. Results: The mean shift in the conventional directions, namely, vertical, longitudinal, and lateral was 0.17 cm, 0.19 cm, and 0.11 cm. There was significant change in vertical shift when first three fractions were compared with rest of the treatment with daily CBCT. When the effect of 6D couch was nullified, all directions showed increased error with longitudinal shift being significant. The number of setup errors of magnitude >0.3 cm was more significant when only conventional shifts were applied as compared with 6D couch. There was significant decrease in volume of brain parenchyma irradiated when margin of PTV was reduced from 0.5 cm to 0.3 cm. Conclusion: Daily CBCT along with 6D couch correction can reduce setup error which allows reduction in PTV margin during radiotherapy planning in turn improving the therapeutic index.