AIM:Surface mould brachytherapy (SMBT) is an effective non-invasive treatment option for patients with skin cancer and other superficial tumours. We describe the detailed technique of uniquely treated patients of various histology using customized tailor-made surface moulds and evaluated clinical outcomes, toxicity profile, and quality of life of patients treated with SMBT. MATERIALS AND METHODS:In this retrospective study, we have evaluated nine patients treated with surface moulds using iridium-192-based high-dose-rate brachytherapy. RESULTS:The median age was 34 years. The histopathological diagnosis included squamous cell carcinoma (n=4), followed by giant cell tumour (n=2), and 1 each of angiosarcoma, dermatofibrosarcoma protuberans, and clear cell sarcoma. The most common radiotherapy dose schedule was 60-66 Gray at 2 Gray per fraction. After a median follow-up of 24 months, local control was 100%. At the end of five years, overall survival (OS) and disease-free survival (DFS) were 88.89%. The maximum acute skin and subcutaneous toxicity grade II was observed in 5 (55.6%) patients and grade III in 4 (44.4%) patients, maximum late toxicity was grade III in 3 (33.3%) patients. Poorer Dermatology Life Quality Index scores were statistically significantly associated with higher overdose index (>0) (P=.039), and V150% >40% (P=.039). CONCLUSION:SMBT is an effective modality to achieve excellent local control in patients of skin and superficial tumours. After five years, OS and DFS both were 88.89%. It was well tolerated with manageable grade II,III acute and late skin toxicities.

PURPOSE:To compare the effectiveness of the inverse planning simulated annealing (IPSA) and hybrid inverse planning optimization (HIPO) algorithms in interstitial HDR brachytherapy for treatment of cervical cancer. METHODS AND MATERIALS:A dosimetric study was conducted on 46 cervical cancer patients who underwent multi catheter interstitial cervical HDR brachytherapy using the Martinez Universal Perineal Interstitial Template (MUPIT). Dosimetric parameters, plan evaluation indices, and mean treatment time were assessed for each algorithm. All the parameters were compared using statistical analysis. RESULTS:With HIPO, significant improvements were observed in D90, D100, V100, and V200 (P < 0.05). Additionally, HIPO plans demonstrated lower doses to the bladder (B2cc) as compared to IPSA plans, whereas IPSA plans exhibited lower rectum (R2cc) and sigmoid (S2cc) doses, with statistical significance observed only for sigmoid doses. HIPO plans had better results in the plan evaluation indices such as CI, COIN, DHI, DNR, ODI, EI, NV100, GFB, GFR, GF, PQI1, PQI2, and PQS with statistical significance (P < 0.05) except for GFS. Moreover, HIPO plans had shorter mean treatment time compared to IPSA plans by 5.52 seconds, although this difference did not reach statistical significance. It was found that HIPO plans demonstrated superior dose-volumetric parameters for the high-risk clinical target volume (HR-CTV). CONCLUSIONS:In conclusion, HIPO emerged as the preferred algorithm for interstitial cervical HDR brachytherapy due to improved dose distribution in HR-CTV and plan quality as well.

Designing an intracavitary brachytherapy applicator with a 3D printer using Polyamide12 for Tandem-Ovoid configuration. Further, to evaluate its feasibility and initial clinical use for the treatment of cervical cancer patients with a High Dose Rate (HDR) brachytherapy system. SolidWorks, Computer Aided design software was used for the design of the intracavitary brachytherapy applicator. Hewlett-Packard Jet Fusion 4200 was used for printing different parts of applicators with Polyamide12 (PA12) material. Radiograph and CT images of printed material parts were taken in the air and water medium to see the visualization. Before use in the patient, necessary quality assurance tests were carried out by coupling it with a microSelectron HDR machine. X-ray markers were used to visualize the source path inside the uterine and vaginal tandems. Physical and clinical evaluations were performed with a prototype 3D-printed applicator to check its suitability for clinical use. Final Applicator design was created from multiple hit and trial methods in SolidWorks. Printed PA12 of ovoid parts having a mean Hounsfield unit (HU) value of − 75 HU. Quality tests on the PA12 intracavitary applicator performed with the microSelectron HDR brachytherapy machine were passed. The chances of uterine perforation were less due to the semi-rigidity of the PA12 applicator. The newly designed T-O-based applicator and dummy marker do not produce any artifacts on the CT images. A low-cost flexible plastic applicator was developed that allowed the user to guide the tandem into the uterus of a patient. The developed PA12 intracavitary brachytherapy applicator did not produce artifacts on CT images.

Introduction: The fundamental principle of the Fricke gel dosimeter involves the oxidation of ferric ions upon exposure to radiation. However, a significant limitation of this dosimeter is the post-irradiation diffusion of ferric ions, which can result in the degradation of spatial dose information. Material and Methods: Gels were prepared using 300 bloom gelatin, deionized water, sulfuric acid, ferrous ammonium sulfate, and xylenol orange dye (Sigma-Aldrich). The solution was then poured into 10 ml plastic cuvettes.. The gel samples were refrigerated at various temperatures for 1 to 10 days and irradiated within a water bath environment utilizing a telecobalt unit (Phoenix, Theratronics) employing parallel opposed beams. Spectrophotometric analysis at a wavelength of 585 nm was used to measured optical density changes with dose.. This procedure was repeated across gel formulations prepared under differing pH conditions. Results: The gel's optimum pH value, which was stored for 10 days at 5° C, showed a linear response up to 10 Gy, although the storage time was longer than that of the gels with low (0.3) and high pH (1.3). The auto oxidation rate was determined and found to be less for non-irradiated gel batches stored at 5° C in relation to the gel samples at room temperature and freezing temperature. Conclusion: The dose response of the dosimeter is highly dependent on its pH, composition, alkaline residuals, and pre-irradiation storing conditions.. We observed the optimum pH is 1, at which the dosimeter shows a maximum response. Storing gel samples at 5°C notably reduces the Fe2+ to Fe3+ auto-oxidation rate.

The purpose of this study was to compare intravaginal brachytherapy (IVBT) with interstitial brachytherapy (ISBT) in patients presenting with residual or recurrent disease after inadvertent hysterectomy for cervical cancer. Records of consecutive patients with cervical cancer, registered in the Radiotherapy Outpatient Department (RTOPD) between March 2018 and March 2021, who had inadvertent hysterectomy followed by external beam radiotherapy (EBRT) and IVBT (n = 15) or ISBT (n = 15) were analyzed retrospectively. All the patients received a dose of 45–50 Gy/25 fractions in 5 weeks by EBRT with concurrent cisplatin. A dose of 6 Gy/fraction/week for two consecutive weeks was prescribed at 5 mm from the surface of the vaginal cylinder in the IVBT arm. Patients in the ISBT arm were treated with 6 Gy/fraction for four fractions over two days with Martinez Universal Perineal Interstitial Template (MUPIT). Overall survival (OS) and disease-free survival (DFS) were the primary endpoints. Acute and late toxicities were the secondary endpoints. Median follow-up (FU) was 24.3 months and 32.8 months in the IVBT and ISBT arms respectively. Most of the patients failed within 12–18 months after brachytherapy. The 3-year OS for IVBT and ISBT arms were 54% and 93% respectively (p = 0.011). The 3-year DFS for IVBT and ISBT arms were 42% and 93% respectively(p = 0.023). Both the arms had similar acute & late toxicities. ISBT had significantly better survival outcomes in terms of OS, and DFS with similar toxicity as compared to IVBT in patients with residual or recurrent disease after inadvertent hysterectomy for cervical cancer.

Purpose:The present study evaluated the dosimetric impact and compared the dose variations between the advanced collapsed cone engine (Task Group 186) and Task Group 43 plans for cervical cancer using tandem and ovoid applicators. Material and methods:Thirty cervical cancer patients underwent iridium-192 (192Ir) high-dose-rate (HDR) intra-cavitary brachytherapy using tandem and ovoid applicator. Original treatment plans for all patients were created using TG-43 dose calculation formalism. Subsequently, these plans were re-calculated using ACE (TG-186) algorithm and were not re-optimized, so that dwell time and dwell positions were identical in both plans. High-risk clinical target volume and organs at risk were contoured in each dataset. Significant air gaps within region of interest and use of high density applicator materials were also considered. The assessment encompassed a point-based evaluation, extraction of dosimetric parameters from dose-volume histogram (DVH), and plan evaluation indices for each algorithm. Results:Compared with ACE (TG-186) plans, TG-43 plans predicted higher doses for point A, point B, D90, D100, V100, V150, V200, and V300 for HR-CTV (p < 0.05). Similarly, TG-43 plans indicated higher doses for bladder point, rectum point, D0.1cm 3, D10cm 3, and D2cm 3 for bladder, rectum, and sigmoid (p < 0.05). Additionally, overall plan quality score (PQS) was significantly greater in plans calculated with ACE (TG-186) formalism than in TG-43 plans (p < 0.05). In TG-186 (ACE) plans, gradient index (GI) was found to be lower than that in TG-43 plans (p < 0.05). Conclusions:TG-43 tends to overestimate doses compared with ACE (TG-186); nonetheless, both methods meet clinical standards. Material differences in the applicator are notable, and dose overestimations by TG-43 are within 5%.

Purpose To correlate the late bladder toxicity with the dose received by sub-volumes of bladder and urethra in patients treated with Interstitial brachytherapy for locally advanced cervical cancer. Material and Methods A total of 37 untreated patients, with ECOG 0-2 registered from January 2020 to March 2023 with histologically proven carcinoma cervix from stage IIB to IVA were included in the study. All the patients received external beam radiation therapy (EBRT) on 6 MV LINAC using VMAT to a dose of 45 Gy to the pelvis and 55 Gy to the positive nodal disease (Pelvic & Paraaortic) with simultaneous integrated boost (SIB) along with weekly concurrent cisplatin. Post-EBRT response assessment was done with MRI whole abdomen. An interstitial brachytherapy dose of 6 Gy per fraction for 4 fractions minimum of 6 hours apart was prescribed to HR CTV, contoured as per ICRU 89. All the patients were scanned with a 1 mm slice thickness & 3-D planning was done on the Oncentra treatment planning system. OAR volumes (bladder, bladder trigone, bladder wall, Periurethral tissue, urethra, rectum, rectal wall) were contoured. Toxicities were recorded on each follow-up and were graded as per RTOG criteria. Results The median follow-up was 31.2 months (6.5-49.6 months). 40.5 % of patients had late bladder toxicity with a mean duration of appearance at 21.8 months and a median duration of 22 months (10-39.5 months). 16.2 % of patients had Grade 1, 16.2% had Grade 2, and 8.1% had Grade 3 late bladder toxicity. Doses to 2cc, 1cc, 0.1 cc volume of Bladder wall (p<0.001), 2cc & 1cc volume of periurethral tissue (p=0.001 & p=0.004, respectively) and 1cc & 0.1cc volume of the urethra (p=0.019 & p=0.007) were significantly associated with the development of late bladder toxicity. It has been found that there is a threshold dose for bladder subvolumes (2cc,1cc,0.1cc) for the development of different grades of toxicity, given in Table 1. However, since the volume of the urethra is less the threshold doses have to be taken for 1cc and 0.1 cc volume. Conclusion The dose of 99.3 Gy and 67.6 Gy to 2cc of the bladder wall and periurethral tissue, respectively, are associated with the development of grade 3 late bladder toxicity. Preventive efforts can be taken at the time of planning to limit the dose to these subvolumes when possible, in order to reduce late bladder toxicity

Purpose: The present study evaluated the dosimetric impact and compared the dose variations between the advanced collapsed cone engine (Task Group 186) and Task Group 43 plans for cervical cancer using tandem and ovoid applicators. Material and methods: Thirty cervical cancer patients underwent iridium-192 (192Ir) 192 Ir) high-dose-rate (HDR) intra-cavitary brachytherapy using tandem and ovoid applicator. Original treatment plans for all patients were created using TG-43 dose calculation formalism. Subsequently, these plans were re-calculated using ACE (TG-186) algorithm and were not re-optimized, so that dwell time and dwell positions were identical in both plans. High-risk clinical target volume and organs at risk were contoured in each dataset. Significant air gaps within region of interest and use of high density applicator materials were also considered. The assessment encompassed a point-based evaluation, extraction of dosimetric parameters from dose-volume histogram (DVH), and plan evaluation indices for each algorithm. Results: Compared with ACE (TG-186) plans, TG-43 plans predicted higher doses for point A, point B, D90, 90 , D 100 , V 100 , V 150 , V 200 , and V 300 for HR-CTV (p p < 0.05). Similarly, TG-43 plans indicated higher doses for bladder point, rectum point, D 0.1cm 3 , D 10cm3 , and D 2cm3 for bladder, rectum, and sigmoid (p p < 0.05). Additionally, overall plan quality score (PQS) was significantly greater in plans calculated with ACE (TG-186) formalism than in TG-43 plans (p p < 0.05). In TG- 186 (ACE) plans, gradient index (GI) was found to be lower than that in TG-43 plans (p p < 0.05). Conclusions: TG-43 tends to overestimate doses compared with ACE (TG-186); nonetheless, both methods meet clinical standards. Material differences in the applicator are notable, and dose overestimations by TG-43 are within 5%. J Contemp Brachytherapy 2024; ; 16, 4: 289-296

PURPOSE: To study the effect of various dose-volume parameters on the severity of vaginal stricture (VS) and the correlation of the latter with the posterior-inferior border of symphysis (PIBS) points in locally advanced cervical cancer patients treated with concurrent chemoradiation and brachytherapy.METHODS AND MATERIALS: A prospective study was done on 45 histologically proven locally advanced cervical cancer patients between January 2020 and March 2021. All of them were treated with concurrent chemoradiation with 6 MV photon linear accelerator to a dose of 45 Gy/25 fractions in 5 weeks. Twenty-three patients were treated with intracavitary brachytherapy with a dose of 7 Gy/fraction/week for three fractions. Twenty-two patients were treated with interstitial brachytherapy, with 6 Gy/fraction for four fractions, each fraction 6 h apart. Grading of VS was done as per Common Terminology Criteria for Adverse Events version 5.RESULTS: The median followup was 21.5 months. About 37.8% of patients had VS with a median duration of 8.0 months (4.0-12 months). About 22.2% had Grade 1, 6.7% had Grade 2, and 8.9% had Grade 3 toxicity. Doses at PIBS and PIBS -2 points had no correlation with vaginal toxicity, however, the dose at PIBS + 2 was significantly associated with VS ( p = 0.004). The treated length of the vagina at the time of brachytherapy ( p = 0.001), initial tumor volume ( p = 0.009), and vaginal involvement after completion of external beam radiotherapy (EBRT) ( p = 0.01) were also statistically significant with the development of VS of Grade 2 or more.CONCLUSIONS: Dose at PIBS + 2, treated length of the vagina with brachytherapy, initial tumor volume, and post-EBRT vaginal involvement are strong predictors for the severity of VS. (c) 2023 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

The quality of life (QoL) of patients with cervical cancer is of paramount concern in addition to their survival outcomes. The rationale of this study was to assess the QoL of the patients of locally advanced cervical cancer treated with chemoradiation and to estimate its difference when treated with two different brachytherapy (BT) techniques: Intracavitary (ICRT) or Interstitial brachytherapy (ISBT). Forty-five, previously untreated, carcinoma cervix patients of FIGO stage IIB to IVA who were registered at the Institute of medical sciences, Banaras Hindu University, from December 2019 to March 2021 were included in the study. The patients were randomized into two BT arms, ICRT & ISBT, using simple randomization. The QoL was studied using structured European Organization for Research and Treatment of Cancer (EORTC) quality of life questionnaires C30 (QLQ-C30), and Cervical Cancer Module (Cx24). The baseline observations were recorded on the day of registration and then after three months of completion of treatment. These patients were treated with 6 MV photon with VMAT to a dose of 45Gy-55Gy in 25 fractions followed by ICRT (7Gy/#,3 #, 1#/week) or ISBT (6 Gy/#, 4#, 6 hours apart over 2 consecutive days). BT planning was done on Oncentra treatment planning system. At 3 months of treatment completion, mean scores of global health status were 84.93 and 77.8 in the ICR and ISBT arm (p=0.019). The mean scores for physical functioning, emotional functioning, and social functioning were 92.81 and 94.3 (p=0.039), 96.75 and 87.16 (p= 0.000), 56.76 and 53.34 (p=0.002) for ICR and ISBT arms respectively. The difference in mean scores of fatigue, menopausal symptoms, the sexual worry was significant. The increment in peripheral neuropathy scores was more in the ISBT arm as compared to the ICRT arm (p=0.05) post-treatment completion. There was also a significant increase in sexual activity and an improvement in sexual enjoyment scores for the patients treated with ISBT (p=0.02). QoL was improved in both treatment arms. However, the improvement was significantly more in the patients treated with intracavitary brachytherapy as compared to those treated with interstitial brachytherapy.

Purpose: To explore the feasibility and efficacy of interstitial brachytherapy application for nonresectable and chemo-resistant malignant liver and lung lesions. Materials and Methods: Percutaneous high-dose-rate interstitial brachytherapy (HDR ISBT) was applied in nine lesions of seven middle-aged patients with advanced carcinoma (five patients with liver lesion and two patients with lung lesion). All patients were surgically ineligible. All patients had already received systemic chemotherapy. Under computed tomography (CT) guidance (for lung lesion) or ultrasonography (USG) guidance (for liver lesion), a single stainless steel brachytherapy needle was inserted percutaneously in patients with lesion size <= 4 centimeter (cm) and multiple needles were inserted in patients of lesion size >4cm. A single dose of 15 Gy to 20 Gy with HDR ISBT was prescribed at the periphery of the lesion. The needles were removed just after treatment. Patients were kept under observation for 24 h after treatment. Results: The median size of the lesion was 6.5 cm. In all the cases of liver lesion, more than 75% shrinkage of tumor volume in follow-up at 6 mo was observed. It was more than 50% for lung lesion. None of the patients had developed significant complications as on the median follow up period of 15 mo (ranges 3-27 mo). Conclusions: Percutaneous CT-guided high-dose-rate interstitial brachytherapy is a minimally invasive, safe, and feasible treatment option with minimal complication for inoperable, chemo resistant, advanced cancers with encouraging treatment outcomes.

The study was conducted with the aim to compare four radiotherapy schedules in terms of overall survival (OS), disease-free survival (DFS), acute & late toxicities in locally advanced cervical cancer. A total of 73 patients (ECOG 0-1) with histologically proven cervical cancer, FIGO stage IIB-IVA were included in the study (December 2020 to July 2022). All the patients were treated with 6 MV Linear Accelerator with Volumetric modulated arc therapy (VMAT) to the whole pelvis. This was followed by High dose rate brachytherapy (HDR-BT) with intracavitary (ICRT) or interstitial (ISBT) application. Patients were randomized into four treatment arms: Arm A- EBRT: 45 Gy/ 25 fractions/ 5 weeks; ISBT: 6 Gy / fraction, 4 fractions, twice daily. Arm B- EBRT: 50 Gy/ 25 fractions/ 5 weeks; ISBT: 6 Gy / fraction, 4 fractions, twice daily. Arm C- EBRT: 45 Gy/ 25 fractions/ 5 weeks; ICRT: 7 Gy / fraction, 4 fractions, weekly. Arm D- EBRT: 45 Gy/ 25 fractions/ 5 weeks; ICRT: 7 Gy / fraction, 3 fractions, weekly. Positive lymph nodes were treated with simultaneous integrated boost (SIB) of 55 Gy in 25 fractions and concurrent cisplatin at 40mg/m2 in all four arms. The patients were contoured and planned on CT based planning system. Response assessment was done with functional MRI after completion of EBRT & after 3 months of treatment completion. The median follow-up of the study was 19.4 months. The mean OS in arms A, B, C & D was 32.3, 15.7, 15.3 & 34.5 months respectively (p= 0.954). The mean DFS in arms A, B, C & D was 31.9, 11.9, 11.0, and 28.8 months respectively (p= 0.562). Grade 3/4 acute hematological toxicity was seen in arm A (18.2%), C (5.6%) & D (17.3%). Grade 3/4 GI toxicity was present in arms C (5.6%) & D (13%). Radiation proctitis was significantly more in the arm A & B (p=0.007). All the treatment arms were similar in survival outcomes and acute toxicities. However, radiation proctitis was significantly more in patients receiving ISBT.

Purpose.- To evaluate the impact of dwell time deviation constraint (DTDC) on the quality of IPSA optimized treatment plans in comparison with graphical plans using plan quality scores (PQS). Material and methods. - Seventy optimized plans (graphical & IPSA with different DTDC values) of ten cervical cancer patients were generated. Various DVH parameters like D-90, V-100, V-150, V-200, V-300 were compared to evaluate the impact of DTDC on target coverage and high dose regions inside target for different plans. Similarly, for the OAR dose, values of D-2cc were compared. Various planning parameters like CI, COIN, DHI, DNR, ODI, EI and gain factor (GF) for different OARs were calculated. Based on theseindices a plan quality score (PQS) was formulated and calculated. PQS values were used to see the impact of DTDC on plan quality of IPSA in comparison with dosimetric quality of graphical plan. Results. - We have found that target coverage is similar for IPSA and graphically optimized treatment plans. However, dose homogeneity was improved in IPSA compared to graphical optimization where as conformality was better in graphically optimized plans. OAR dose was less in IPSA plans. High-dose regions inside the target were also reduced in IPSA comparatively. However, IPSA plans optimized with various values of DTDC did not necessarily reduce high-dose regions beyond 0.6. Plan quality scores (PQS) were 6.31, 6.31, 6.34, and 6.17 for the graphically optimized plan, IPSA with DTDC values of 0.0, 0.4, and 1.0 respectively. Conclusion. - We found that IPSA is dosimetrically advantageous over graphical optimization. IPSA witha DTDC value of 0.4 improved overall plan quality. However, DTDC value beyond 0.6 produces dosimetrically sub-optimal plans hence the use of DTDC should be very selective and limited. (c) 2023 Societe francaise de radiotherapie oncologique (SFRO). Published by Elsevier Masson SAS. Allrights reserved.

Purpose: To find out the simple relationship between Total Reference Air Kerma (TRAK) and various isodose volumes. Calculated isodose volumes were compared with experimental data for revised Manchester and International Commission on Radiation Units and measurements (ICRU)-89 Point A-based treatment plans. The accuracy of the formula was compared with the results of other relationships available in the literature. Materials and Methods: Dosimetric data from 62 intracavitary brachytherapy (ICBT) treatment plans of 31 patients with cervical cancer were studied. Each patient had treatment plans normalized to revised Manchester and ICRU-89 Points A (Aflange and Aicru89). For each treatment plan, TRAK values, V350, V700, V1050, and V1400 were obtained. The modeling curve was plotted between Isodose volume (Vd) and the ratio of d/TRAK obtained from Aflange plans to get a mathematical relation. The results of this formula were compared with the experimental data and outcomes of other formulas available in the literature. A paired-sample t-test was performed to assess the statistical significance. Results: In the case of revised Manchester-based Aflange normalization plans, the mean isodose volume of V350, V700, V1050, and V1400 were 285.98 ± 32.3 cm3, 101.96 ± 10.63 cm3, 52.71 ± 4.72 cm3, and 31.44 ± 2.33 cm3 respectively. Likewise, for ICRU-89 based Aicru89 normalization plans, the mean isodose volumes of V350, V700, V1050, and V1400 were 304.11 ± 26.17 cm3, 108.88 ± 8.29 cm3, 56.62 ± 3.69 cm3 and 34 ± 2.23 cm3 respectively. The mean difference was significant. The Mathematical relationship developed was [INLINE:1]. No correlation was found between TRAK and D0.1cm3,D2cm3 for organs at risk. Conclusions: The developed formula calculated isodose volumes within the accuracy of ± 3% in ICBT plans.

Purpose: A comparison of simultaneous integrated boost (SIB) with sequential boost (SEQ) using intensity-modulated radiotherapy along with concurrent cisplatin in locally advanced head and neck cancer (HNC) was made with regard to their survival outcomes and toxicity profile. Materials and Methods: A total of 34 patients were enrolled between October 2016 and March 2019. They were randomized into two arms, SIB and SEQB. All patients were treated with 6 MV photon beam on Linear Accelerator with weekly concurrent cisplatin at 35 mg/m2. Overall survival (OS) and disease-free survival (DFS) were the primary end points and acute and late toxicities were the secondary end points. Results: The median follow-up period was 40.6 and 37.3 months for SIB and SEQB, respectively. At the end of 5 years, the median OS was 40.6 and 37.3 months (P = 0.947) and the median DFS was 35.1 and 37.3 months in the SIB and SEQB arms, respectively (P = 0.991). Complete response at 3 months was 64.7% and 76.5% and partial response was 23.5% and 17.6%, whereas progressive disease was 11.8% and 5.9% in SIB and SEQB arms, respectively. Acute dermatitis, mucositis, dysphagia, and salivary gland toxicities were higher in the SIB arm compared to the SEQB arm. Conclusion: SIB and SEQ arms were comparable in terms of OS and DFS. However, the acute toxicities were higher in the SIB arm, although the difference was not significant, compared to the SEQB arm.

Purpose To co-relate vaginal stricture with the radiotherapy dose at the posterior inferior border of symphysis (PIBS) points in the patients with locally advanced cervical cancer. Material and Methods A total of 45 untreated patients, with ECOG 0-2 registered from January 2020 to March 2021 with histopathologically proven carcinoma cervix from stage IIB to IVA were included in the study. All the patients received external beam radiation therapy (EBRT) on 6 MV Linear Accelerator with Volumetric modulated arc therapy (VMAT) to a dose of 45 Gy in 25 fractions to the pelvis and 55 Gy in 25 fractions to the positive nodal disease (Pelvic & Paraaortic) with simultaneous integrated boost (SIB) along with weekly concurrent cisplatin at 40 mg/m2. Twenty-three patients were treated with Intracavitary Brachytherapy (ICRT) with a dose of 7 Gy per fraction for three weekly fractions. All the patients were scanned with 1 mm slice thickness & 3-D planning was done on Oncentra treatment planning system. The contouring of targets was done as per ICRU 89 in case of ISBT. Twenty-two patients were treated with interstitial brachytherapy (ISBT), with 6 Gy per fraction for four fractions. The dose was prescribed to HR CTV and point A for ISBT and ICRT respectively. The time gap between two fractions for patients treated with ISBT was at least six hours. Evaluation of disease status and treatment response was done with Functional MRI Pelvis before, during, and 3 months after completion of radiotherapy. Late vaginal morbidity was assessed as per CTCAE v5.0. Results The mean duration of follow-up was 12.17 months (1-24.3 months).35.6 % of patients had vaginal stricture with a mean duration of appearance at 7.55 months and a median duration of 8.0 months (3.9-12 months). 24.4% had grade 1 vaginal toxicity, 6.7% had grade 2 vaginal toxicity, 4.4% had grade 3 toxicity. Doses at PIBS 0, PIBS minus points had no correlation with vaginal toxicity, however, dose at PIBS plus 2 was significantly associated with vaginal stricture (p =0.03). Threshold doses and time of appearance of vaginal toxicity are shown in table 1. Conclusion Dose at PIBS + 2 is a strong predictor for vaginal stricture. Efforts during brachytherapy planning should be taken to reduce the dose to PIBS +2 so as to reduce the probability of vaginal stricture.

Purpose:Development and validation of a simple and convenient computational program in MATLAB environment for estimating the tumor control probability (TCP) and the normal tissue complication probability (NTCP), as a decision support system for routine plan evaluation. Materials and Methods:We developed an in-house software using MATLAB 2016b (Mathworks) for estimating TCP and NTCP named as RBMODELV1. The program contains Niemierko free equivalent uniform dose (EUD) program code provided in authors research article. For rest of radiobiological (RB) models in the software separate coding is performed. The program accepts cumulative dose-volume histogram file in (.txt) format containing two columns dose and volume. A set of two RB parameters were prepared, default and user-dependent in excel sheet named as RBDATA. We cross-validated results of RBMODELV1 software with BioSuite software for Poisson's TCP model and Lyman-Kutcher-Burman (LKB) model. A set of total 20 patient's data of head and neck site took under study and respective TCP and NTCP calculated by all the RB models and compared. Results:This is the first study in which we tried to establish correlation between the mean doses (EUD) received by parallel structure (parotid gland and oral cavity) and predicted percentage of NTCP values. It is found that mean dose in the range of 35-40 Gy for parotid gland can result in more than 50% NTCP predicted by all four RB models. Similarly oral cavity receiving mean dose in the range of 53-58 Gy can results in more than 35% NTCP predicted by all the four models. There is <3% variation observed between TCP calculated by BioSuite and RBMODELV1 software and <4% variation observed between predicted NTCP for parotid gland and oral cavity OAR from LKB model by both the software. Conclusion:We created simple software RBMODELV1 which can be used as a research tool as well as decision support system.