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Author(s): Gurpreet Kaur [1]; Pardeep Garg [1]; Vinod Kumar Dangwal (corresponding author) [2]; Baltej Singh [3]; Garima Gaur [1]; Romikant Grover [1]; Simrandeep Singh [1]; Rachana Sharma [4] INTRODUCTION In [...], Introduction: The purpose of the study was to calculate, tumor control probability (TCP) and normal tissue complication probability (NTCP) in cervical cancer patients and to clinically correlate the outcomes with a follow-up period of 24 months. Materials and Methods: One hundred and fifty patients were included in the present study who received 46 Gy/23 fractions/4½ weeks of external beam radiotherapy with concurrent cisplatin chemotherapy, followed by intracavitary brachytherapy of 3 different fractionations regimens, i.e., 9.5 Gy per fraction of two fractions (50 patients in Arm1), 7.5 Gy per fraction of three fractions (50 patients in Arm2), and 6.0 Gy per fraction of four fractions (50 patients in Arm3). Results: The median TCP value for Arm1, Arm2, and Arm3 was 99.6%, 94%, and 98.1%, respectively, (P < 0.01). The median NTCP value for bladder in Arm1, Arm2, and Arm3 was 0.17%, 0.04%, and 0.07%, respectively, (P = 0.05). The median NTCP value for rectum in Arm1, Arm2, and Arm3 was 4.73%, 4.35%, and 3.17%, respectively, (P = 0.052). The overall survival (OS) of 90%, 86%, and 84% was found for Arm1, Arm2, and Arm3, respectively, at 24 months of follow-up. Conclusion: TCP, NTCP, and OS rates were found higher in Arm1 as compared to the other two arms. The complications found in all arms were less, low grade, and manageable. Hence, Arm1, i.e., 9.5 Gy per fraction of two fractions can be concluded as the optimum fractionation regime in terms of radiobiological parameters as well as overall patient comfort. Keywords: Brachytherapy, carcinoma uterine cervix, normal tissue complication probability, radiotherapy, tumor control probability

The Covid-19 pandemic limitation has led to a variety of psychiatric manifestations in humans. These effects were brought about by insufficient planning and a lack of awareness of the epidemic. Infrastructure, human resources, and steady supply are all important, as is the transportation of medications, food, and surgical supplies for the patients. Managing biomedical waste, which includes collecting and segregating it, comes last, includes its storage and transit. Including the challenges, they face with regards to the disposal of dead bodies. [ABSTRACT FROM AUTHOR]

This investigation aimed to measure and commission small unflat photon beams using the detectors described in our previous study10. Furthermore, the dosimetric parameters of small-field unflat and flat photon beams were compared to provide a better interpretation of beam energy and spectrum. The TrueBeam linear accelerator (TrueBeam LINAC, Varian Medical Systems) was employed in this study. The 10 and 6 MV unflat and flat photon beams were used to measure the output factor, depth dose, and beam profile of small-fields ranging in size from 1 cm x 1 cm to 6 cm x 6 cm. All measurements were performed according to the TRS-483 protocols established by the International Atomic Energy Agency. For both 10 and 6 MV, the output factors in unflat beam were significantly higher than in flat beam. The study found that unflat beam penumbras were slightly smaller than flat beam penumbras for both photon energies, which may improve tumor conformity and reduce doses to normal organs. The unflat photon beams had higher suface doses and lower depth doses at 10 cm than the flat photon beams for both energies, leading to considerably more beam energy degradation for unflat beams. The findings of this work are consistent with previously published data, and they will be useful for future research and LINAC commissioning. [ABSTRACT FROM AUTHOR]

Background: The aim of the current study was to compare three different dose‑calculating algorithms, i.e., superposition (SP), fast SP (FSP), and convolution (CV), for breast cancer patients treated with intensity‑modulated radiotherapy (IMRT) and field‑in‑Field forward plan IMRT (FiF‑FP‑IMRT). Materials and Methods: The current retrospective study involved 100 postmastectomy breast cancer patients who were given radiotherapy using IMRT and FiF‑FP‑IMRT planning techniques. All the initially SP‑calculated plans were recalculated with the same monitor units for FSP and CV algorithm without change in any of the other planning parameters. The isodose distribution and various plan evaluating parameters, for example, conformity index (CI), homogeneity index, and uniformity index target volume and normal structure doses were compared and analyzed for all the different algorithm calculated plans. Results: In the IMRT plans, all the target and normal structure dose‑volume parameters showed a significant difference between all the three different algorithms with P < 0.05. In the FiF‑FP‑IMRT plans, CV algorithm showed a significant difference in most of the target and normal structure dose‑volume parameters. Among quality indexes, only CI showed a significant difference between all the algorithms in both the planning techniques. R50 showed a significant difference with the CV algorithm in both the planning techniques. Conclusion: The change in the dose calculation algorithm resulted in dosimetric changes which must be evaluated by the medical physicists and oncologists while evaluating treatment plans. In the current study with breast patients, the results obtained for target and normal structure doses using the CV algorithm are overestimated as compared to SP and FSP algorithms, producing variable results in air and bony normal structures. However, the ipsilateral lung V5 parameter and the ipsilateral humeral head mean dose were found to be underestimated by the CV algorithm as compared to the SP and FSP algorithm in both the planning techniques. [ABSTRACT FROM AUTHOR]

Introduction: The dose prescription point in high dose rate (HDR) intracavitory brachytherapy (ICBT) of cervical cancer is Manchester point A but the localization of this point has a wider variation. To minimize these variations, the American Brachytherapy Society (ABS) introduced a new definition of point A and named it as point H. In this study, these two points have been compared in terms of dosimetric parameters. Material and Methods: Twenty HDR ICBT of cervical cancer patients were retrospectively evaluated with Manchester point A and ABS point H. Target volume covered by prescribed dose (TV), dose to 2cc (D2cc) of the bladder and rectum were noted for both points. Statistical analysis using a two-tailed paired t-test was performed to compare dosimetric parameters of both the points of prescription. The maximum value, minimum value, and mean ± standard deviation along with the p value have been noted. Results: On average, point H was 4.0mm ± 6.4mm shifted (superior/inferior) from point A, along the tandem direction. The average TV when the prescription was done at point H (TVH) was 33.7cc ± 10.1cc which was higher than the average TV when the prescription was done at point A (TVA) of 33.3cc ± 9.4 cc.D2cc increased from 63% ± 23% to 68% ± 24% for the rectum and 52% ± 18% to 56% ± 20% for the bladder when the prescription point changed from A to H. Conclusion: As observed, average TV, D2cc of the bladder, and rectum were higher in the case of point H prescription plan (PH) as compared with point A prescription plan (PA). The dose difference between PH and PA was found to be statistically significant, so careful consideration is needed to implementation of new point H in clinical practice. [ABSTRACT FROM AUTHOR]

Background: Surface/skin dose measurement is one of the most challenging tasks for clinical dosimetry in radiotherapy and comparison with almost all the commercially available treatment planning systems (TPSs) brings a significant variation with the measured dose. Aims and Objectives: In the current study, doses calculated from the TPS in the near-surface region for conformal plans (both three-dimensional conformal radiotherapy [3DCRT] and intensity-modulated radiotherapy [IMRT]) of 35 breast cancer patients were evaluated and compared with the doses measured with Markus chamber. Materials and Methods: The computed tomography (CT) images of a solid water slab phantom with a Markus chamber (at different depths ranging from 1 mm to 5 mm from the surface) were taken and imported into the TPS. All the conformal treatment plans made in TPS were executed on a linear accelerator and dose agreements between TPS calculated and chamber measured doses were analysed. Results: Results showed that this TPS underestimated the calculated doses in the superficial region by up to 26% and 21%, respectively, with respect to mean and maximum dose values obtained within the effective volume of the chamber used. Conclusion: The uncertainty of doses in the superficial region should be kept in mind when evaluating treatment plans for superficial tumours in TPS. [ABSTRACT FROM AUTHOR]