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Multiple fractions of High Dose Rate (HDR) brachytherapy along with external beam therapy is the common method of treatment for cancer of the uterine cervix. Urinary bladder and rectum are the organs at risk (OARs) that receive a significant dose during treatment. To reduce the dose to these organs, a majority of hospitals use vaginal gauze packing, as it is a simple, nontraumatic, and easy method. This article describes the design and development of an inflatable balloon that can be used along with the applicator as a substitute for gauze packing. The balloon has two parts-the bladder part (B-part) and the rectum part (R-part), both of them are independently inflatable. The selection of the material, its width, length, and thickness are described. A mould/former for making the balloon was designed. Polished steel was used as the mould. This was dipped in specially prepared natural rubber latex (NRL) solution several times; the layers were dried and stripped to get the balloon. The composition of NRL and the compounding recipe of the latex are also described. Physical tests like tensile strength, elongation at break, bursting volume, and radiation attenuation caused by the balloon, were checked. Biological tests for assessing type I and type IV allergies, like dermal irritation and skin irritation tests, were also done.

Aim:The aim of this study is to measure and compare the surface dose of treated breast and contralateral breast with the treatment planning system (TPS) calculated dose using calibrated optically stimulated luminescent dosimeter (OSLD) in an indigenous wax breast phantom.Materials and Methods:Three-dimensional conformal plans were generated in eclipse TPS v. 13 to treat the left breast of a wax phantom for a prescribed dose of 200 cGy. The plans were calculated using anisotropic analytical algorithm (AAA) and Acuros algorithm with 1-mm grid size. Calibrated OSLDs were used to measure the surface dose of treated and contralateral breasts.Results:Large differences were observed between measured and expected doses when OSLDs were read in “reading mode” compared to the “hardware mode.” The consistency in the responses of OSLDs was better (deviation <±5%) in the “hardware mode.” Reasonable agreement between TPS dose and measured dose was found in regions inside the treatment field of treated breast using OSLDs for both algorithms. OSLD measured doses and TPS doses, for the points where the angle of incidence was almost normal, were in good agreement compared to all other locations where the angle of incidence varied from 45° to 70°. The maximum deviation between measured doses and calculated doses with AAA and with Acuros were 2.2% and-12.38%, respectively, for planning target volume breast, and 76% and 77.51%, respectively, for the opposite breast.Conclusion:An independent calibration factor is required before using the OSLDs for in vivo dose measurements. With reference to measured doses using OSLD, the accuracy of skin dose estimation of TPS with AAA was better than with Acuros for both the breasts. In general, a reasonable agreement between TPS doses calculated using AAA and measured doses exists in regions inside treatment field, but unacceptable differences were observed for the points lateral to the opposite breast for both AAA and Acuros.

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Orthogonal film-based treatment planning is the most commonly adopted standard practice of treatment planning for cancer of the uterine cervix using high dose rate brachytherapy (HDR). This study aims at examining the variation in rectal and bladder doses when the same set of orthogonal films was given to different observers. Five physicists were given 35 pairs of orthogonal films obtained from patients who had undergone HDR brachytherapy. They were given the same instructions and asked to plan the case assuming the tumor was centrally placed, using the treatment-planning system, PLATO BPS V13.2. A statistically significant difference was observed in the average rectal (F = 3.407, P = 0.01) and bladder (F = 3.284, P = 0.013) doses and the volumes enclosed by the 100% isodose curve (P < 0.01) obtained by each observer. These variations may be attributed to the differences in the reconstruction of applicators, the selection of source positions in ovoids and the intrauterine (IU) tube, and the differences in the selection of points especially for the rectum, from lateral radiographs. These variations in planning seen within a department can be avoided if a particular source pattern is followed in the intrauterine tube, unless a specific situation demands a change. Variations in the selection of rectal points can be ruled out if the posterior vaginal surface is clearly seen.

Purpose: To measure and compare the skin doses received by treated left breast and contralateral breast (CB) during whole breast radiotherapy using five treatment techniques in an indigenously prepared wax breast phantom. Materials and methods: Computed tomography (CT) images of the breast phantom were used for treatment planning and comparison of skin dose calculated from treatment planning system (TPS) with measured dose. Planning target volume (PTV) and the CB were drawn arbitrarily on the CT images acquired for the breast phantom with 10 numbers of calibrated optically stimulated luminescent dosimeters (OSLDs) fixed on the surface of both breasts. The TPS calculated surface doses of PTV breast and CB for five treatment planning techniques, viz., conventional wedge (CW), irregular surface compensator-based (ISC), field-in-field (FiF), intensity-modulated radiotherapy (IMRT) and rapid arc (RA) techniques were obtained for comparison. The plans were executed in Clinac iX Linear Accelerator with the OSLDs fixed at the same locations on the phantom as in simulation. The TPS calculated mean dose at the surface of the treated left breast and CB was noted for the 10 OSLDs from dose-volume histogram (DVH) and compared with the measured dose. Also, the mean chamber dose at the centre of the left breast was noted from the DVH for comparing with ion chamber measured dose. Results: With reference to the results, it is seen that the dose to the CB is lowest in ISC technique and FiF technique and greatest in IMRT technique. The CW technique also delivered a dose comparable to IMRT to the CB of the phantom. The dose to the surface of PTV breast was highest and comparable in CW plans and FiF plans (68% and 67%) and lowest in IMRT and RA plans (50% each). Findings: Analysis of the results shows that the FiF and ISC techniques are preferred while planning breast radiotherapy due to the reduced dose to the CB.