Brachytherapy最新文献

{"title":"PO13","authors":"Saryleine Ortiz de Choudens, Christina Small-Tom, Lindsey McAlarnen, Susan Duyar, Rebekah Summey, Erin Bishop, Elizabeth Hopp, William Bradley, Denise Uyar, Janet S. Rader, Meena Bedi, Beth Erickson","doi":"10.1016/j.brachy.2023.06.114","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.114","url":null,"abstract":"Purpose Dose intensive image-based brachytherapy has become the gold standard treatment for cervical cancer, with an improvement in disease control and radiation-induced morbidity. A significant contribution to dose escalation has been the addition of needles to intracavitary applicators, with both hybrid and template-based insertions. These applications afford brachytherapists more flexibility of dose shaping and tumor coverage, while sparing organs at risk. Many of these procedures can now be performed in departmental brachytherapy suites within radiation oncology departments, where support from other hospital teams is not always readily available. One of the most feared complications during removal of interstitial brachytherapy applicators is a bleeding event, which can range from minor blood loss to life threatening bleeding. In particular, the use of needles that are inserted into the highly vascular vaginal, cervical and parametrial tissues can increase the risk of these events, including injury of venous and arterial structures. Being prepared for potential bleeding events is of the utmost importance in order to ensure a rapid and effective response. Materials and Methods Our goal is to establish a set of guidelines which can be used to prepare for and treat bleeding events during gynecologic brachytherapy. The proposed methods have been used at our institution and were developed in collaboration with the gynecology oncology team. Results First, we recommend pre-operative evaluation of blood counts following chemoradiation, pre-existing bleeding disorders, anticoagulant use, non-steroidal anti-inflammatory drug use, and disease location. A full pre-operative evaluation by a trained anesthesiologist can expedite this evaluation. Blood counts and electrolytes should be obtained on procedure day and prior to needle insertion, and if necessary, significant pre-procedure abnormalities addressed with transfusions or other supplements. Assessment of the location of residual disease and proximity to nearby vessels, as well as the projected location and number of needles is strategic. Considerations for removal of inpatient applications where multiple fractions have been delivered over several days should include timing of prophylactic anticoagulation discontinuation, pre-pull hemoglobin/hematocrit/platelet levels, and if needed, transfusion prior to applicator removal. For all patients, continuous monitoring of vitals before and during applicator removal, as well as dual IV access and blood type and crossing should be considered. IV fluids should be readily available should bleeding cause a drop in blood pressure. Preparation of a fully equipped vaginal packing kit complete with speculums, ring forceps, packing gauze, saline, lubricant and Monsel's solution is essential. For severe bleeding events, with rapid emergence of symptomatic anemia including tachycardia, hypotension, pallor, dizziness or other subjective symptoms, a rapid response team sh","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135434508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PO99","authors":"Kaile Li","doi":"10.1016/j.brachy.2023.06.200","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.200","url":null,"abstract":"","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135434511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PO44","authors":"Memory Fadziso Bvochora-Nsingo, Rohini Bhatia, Elliphine Gwangwava, Thabiso Itshabeng, Surbhi Grover","doi":"10.1016/j.brachy.2023.06.145","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.145","url":null,"abstract":"Purpose Cervical cancer is the most common cancer treated with radiation in Botswana. There is a single linear accelerator and a single HDR brachytherapy unit in the country, treating a median of 200 cervical cancer cases year. About 80% of these are treated with curative intent, using concurrent chemoradiation with brachytherapy boost. Patients in Botswana often present with advanced disease and very bulky tumours. Traditionally, patients who can not have brachytherapy are sent for external beam boost. This not only adds burden onto the very busy single Linac, but also outcomes of patients are compromised. We highlight here seven cases with novel insertions for patients who would have been deemed ineligible for brachytherapy. Materials and Methods We retrospectively revised the records of cervical cancer patients treated with brachytherapy in January 2023, 29 in total. Brachytherapy was delivered in the final week of external beam radiation, or after completion for bulky tumours. The mean age was 46 years and most patients (22, 76%) presented with stage IIB or IIIB, six patients had undergone hysterectomy for stage IB disease. Applicators available were tandem and ovoids, tandem and ring, tandem and cylinder, and cylinder post hysterectomy. Twelve patients (41%) needed interstitial needles. However, seven patients(24%) would previously have been deemed unsuitable for brachytherapy with these applicators due to: 1. Bulky disease with poor response to external beam brachytherapy (three patients). 2. Effaced or destroyed cervix and cavitation at vault post EBRT, traditional tandem and cylinder would not fit (three patients) 3. Stenosis at vault smallest ovoids could not fit and tandem and cylinder would not give adequate dose to bulky tumour (one patient). Results We successfully used three non-conventional methods to complete brachytherapy using available applicators, to treat the 7 patients who would have been deemed ineligible for brachytherapy. Fig. 1. illustrates images from three of the seven patients treated this way. Patient 1: A 55 year old patient with bulky local disease and poor response to EBRT. On day 55, mass still bulky; failed to insert traditional instruments. We inserted tandem and interstitial wires only with no ovoids. Patient 2: A 42 year old patient with stage IIB cancer of the cervix. Cervix had been completely destroyed post external beam radiation, which then created a small cavity at the vault. No gross residual disease. An intrauterine tandem was inserted, then a small (2cm) cylinder was placed into the vault cavity, followed by three 3.5cm cylinders. Patient 3: A 60 year old patient with Stage IIIB cancer of the cervix with bulk of tumour on the left.The smallest ovoids could not fit at the vault, yet tandem and cylinder would not give enough dose coverage especially to the left. A tandem and left ovoid only were inserted, with interstitial wires on the left. All three patients managed to complete radical chemo radiatio","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135434521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PO80","authors":"Juan Wang, Zezhou Liu, Yansong Liang, Jinxin Zhao, Huiming Yu, Hongtao Zhang, Ke Xu","doi":"10.1016/j.brachy.2023.06.181","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.181","url":null,"abstract":"Purpose To explore the value of modified intraoperative real-time 125I seed implantation planning for lumbar lymph nodes metastases. Method We collected 26 lymph nodes metastases patients, who received 125I seed implantation from January 2015 to December 2021. 13 patients procedure were guided by modified intraoperative real-time treatment plan, and the rest were guided by conventional treatment plan. To compare the differences of the dosimetric parameters between pre-plan and post-plan of the 2 groups, and the percentage difference of the dosimetric parameters between the 2 groups. Then evaluate the curative effect and side effects after 6-month. Result There were no significant differences in dosimetric parameters between pre-plan and post-plan in modified intraoperative real-time treatment plan group, and showed significant differences in V150between pre-plan and post-plan in conventional treatment plan group(z=-3.045,P<0.001), and the rest dosimetric parameters of conventional treatment plan group showed no significant differences beforeand after operation(P>0.05). The percentage difference of V150 between the 2 groups showed statistically significant(z=2.103 ,P=0.004), and the rest dosimetric parameters showed no significant differences(P>0.05).6 months after the brachytherapy, the effective rate of Modified intraoperative real-time treatment plan group was 77%(10/13), and 46%(6/13) in Conventional treatment plan group, and no peritonitis and hemorrhage were observed. Conclusion The application of modified real-time planning improved accuracy of dosimetric, reduced the high dose rate area, and provide guarantee for 125I seed implantation planning for lumbar lymph nodes metastases. To explore the value of modified intraoperative real-time 125I seed implantation planning for lumbar lymph nodes metastases. We collected 26 lymph nodes metastases patients, who received 125I seed implantation from January 2015 to December 2021. 13 patients procedure were guided by modified intraoperative real-time treatment plan, and the rest were guided by conventional treatment plan. To compare the differences of the dosimetric parameters between pre-plan and post-plan of the 2 groups, and the percentage difference of the dosimetric parameters between the 2 groups. Then evaluate the curative effect and side effects after 6-month. There were no significant differences in dosimetric parameters between pre-plan and post-plan in modified intraoperative real-time treatment plan group, and showed significant differences in V150between pre-plan and post-plan in conventional treatment plan group(z=-3.045,P<0.001), and the rest dosimetric parameters of conventional treatment plan group showed no significant differences beforeand after operation(P>0.05). The percentage difference of V150 between the 2 groups showed statistically significant(z=2.103 ,P=0.004), and the rest dosimetric parameters showed no significant differences(P>0.05).6 months after the brachytherapy, the","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135434526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PO47","authors":"Magdalena Anna Stankiewicz","doi":"10.1016/j.brachy.2023.06.148","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.148","url":null,"abstract":"Purpose High-dose-rate (HDR) brachytherapy is a vital part of treatment in patients with locally advanced cervical cancer. Current guidelines recommend the use of image-guided adaptive brachytherapy (IGABT). Several fractionation schedules are used in external beam radiotherapy (EBRT) and brachytherapy (BT). A retrospective analysis of patients treated with radio(chemo)therapy and HDR brachytherapy due to cervical cancer was conducted. We compared the efficacy of two fractionation schedules implemented in our department. Materials and Methods Schedule one (\"5x6 Gy\") consisted of five fractions of 6 Gy delivered within 2.5 weeks. In the majority of patients, the dose was prescribed to point A. Schedule two (\"4x7 Gy\") consisted of four fractions of 7 Gy delivered within two weeks. In all patients, the dose was prescribed to CTV. Local control (LC) and distant metastasis-free survival (DMFS) were calculated. The Kaplan-Meier estimator, log-rank and Mann-Whitney U test were used in statistical analysis. One hundred seventeen patients were included in this analysis. Median age was 57 years (range: 29 - 79). The disease stage was re-assessed according to FIGO 2018 classification. Forty-five percent of patients had FIGO IIIC1 disease, 29% - FIGO IIIB, 15% - FIGO IIB and 6% - FIGO IIIC2. The vast majority of patients (96%) had were diagnosed with planoepithelial carcinoma, 2,5% with cervical adenocarcinoma, one patient with clear cell carcinoma and one with serous carcinoma. The \"5x6 Gy\" fractionation was administered in 79% of patients. The median overall treatment time (OTT) was 58 days (range: 45 - 139 days). The median CTV D90 EQD2 sum of EBRT and BT was 89 Gy (range: 65 - 114 Gy). Results In the \"5x6 Gy\" subgroup, the follow-up was significantly longer (p=0.00006), CTV D90 EQD2 was significantly higher (p=0.0001), and OTT was significantly longer (p=0.02). No other significant differences were observed between the subgroups. They were well balanced in terms of patients' age (p=0.6), histopathological grade of the tumour (p=0.2) and FIGO stage (p=0.07). In the whole group, 5-year LC was 91%, 5-year regional nodal control was 86%, and 5-year DMFS was 80%. The comparison of the two fractionation schedules (\"5x6 Gy\" vs \"4x7 Gy\") revealed that higher CTV D90 EQD2 was not associated with better local or distant control. There were no differences in LC (p=0.79), regional nodal control (p=0.7) or DMFS (p=0.83) between the subgroups. However, better regional nodal control and longer DMFS were observed in patients with OTT≤60 days (p=0.035 and p=0.017, respectively). Conclusions Both fractionation schedules have similar efficacy. A shorter overall treatment time is associated with better regional nodal control and DMFS. However, a longer follow-up is needed to confirm these findings. High-dose-rate (HDR) brachytherapy is a vital part of treatment in patients with locally advanced cervical cancer. Current guidelines recommend the use of image-guided adaptive b","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135434368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PO29","authors":"Firas Mourtada, Ayesha Ali, Wookjin Choi, Rani Anne, Wayne Pinover, Beth Erickson, Ann Klopp, Daniel Petereit, David Gaffney, Emma Fields, Junzo Chino, Catheryn Yashar, Mitchell Kamrava, Marisa Kollmeier, Reza Taleei, Shuying Wan, Yevgeniy Vinogradskiy","doi":"10.1016/j.brachy.2023.06.130","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.130","url":null,"abstract":"A novel mobile cone-beam computed tomography (CBCT) imaging device (Elekta Inc.) aims to improve efficiency with on-demand imaging in the HDR vault during and after applicator insertion. We evaluated whether inter-observer contour variability of standard organs-at-risk (OARs) was similar using this novel CBCT (Ring-CBCT) as compared to diagnostic-quality simulation CT (CT-Sim) for cervical cancer HDR brachytherapy. A patient with stage IIB cervical cancer was implanted with the CT/MR Venezia Tandem (6-cm, 30-deg) with 26-mm dia. Lunar Ovoids. Images were acquired with Ring-CBCT (Elekta ImagingRing v 2.5.2) using 120 kVp, 8 mA, and 0.6x0.6x1.2 mm voxel size, and CT-Sim (Siemens SOMATOM go.Open Pro) using department standard pelvis imaging protocol (120 kVp, 1.17x1.17x1 mm voxel size, 0.8 pitch). Zypher transfer system (Orfit Inc.) was used to move patient to reduce applicator motion. Bladder, rectum, sigmoid, and lower bowel were independently contoured by 11 brachytherapists on Ring-CBCT and CT-Sim in Oncentra TPS. After each session, the physician answered a survey with a score from 1-10 for a qualitative evaluation of their comfort level for each contour. Inter-observer contour variability was quantitatively evaluated using Average Surface Distance, 95% Housdorff Distance, 100% Housdorff Distance, Surface Overlap, Surface Dice, and Volumetric Dice comparisons between a reference contour (RA) and each physician's contour. Wilcoxon signed-rank test was applied to test the statistical difference between the metrics on CT-sim and Ring-CBCT. Eleven physicians completed all four OAR contours on both imaging modalities and completed all surveys. The questionnaire results revealed there was greater confidence in the CT contours when compared to the Ring-CBCT contours. Comfort levels were a median of 10 (9-10) vs. 8 (6-10 (p<0.01) for bladder, 9 (8-10) vs. 8 (4-10) (p<0.01) for rectum, 8.5 (8-10) vs. 6.5 (2-10) (p<0.001) for sigmoid and 8 (7-10) vs. 5 (1-10) (p<0.001) for bowel, respectively. Inter-observer variations in OAR delineation on CT-sim and Ring CBCT are shown in Table 1. Overall, CT-sim showed lower interobserver variation when compared to the Ring-CBCT. There were no statistically significant differences between contour variability with Ring-CBCT when compared to contour variability assessed with CT-sim for most OARs and metrics evaluated. Bladder showed the most prevalent statistically significant variability differences between CT-Sim and Ring-CBCT as evaluated by surface metrics (Average Surface Distance and Hausdorff Distance). Using a multi-center approach and a comprehensive suite of comparison metrics, this study provides the first report of image quality assessment of a novel Ring CBCT for HDR applications. Our data show that for the presented patient, the contours generated using the Ring-CBCT show similar variability when compared to contours generated using standard of care CT-Sim imaging. Based on the physician survey however, OA","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135434373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PO21","authors":"Alvin Kumar, Avtar Raina","doi":"10.1016/j.brachy.2023.06.122","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.122","url":null,"abstract":"Brachytherapy (BT) has been utilized for the treatment of anal cancer for many decades. A previous systematic review had shown benefit of BT boost in patients undergoing curative intent chemo-radiotherapy for anal canal cancer. Despite this, the use of BT boost is still restricted to a few chosen institutions and is typically not mentioned as a therapeutic alternative in the well-known international standards. Barriers to its widespread implementation have been identified as specialised knowledge, complexity, and equipment. There is also not much evidence in literature regarding the use of BT as a sole modality for treating early stage anal cancers. Christchurch Oncology has 12 years’ of clinical experience with High Dose rate intracavitary/ interstitial brachytherapy for Gynaecological and Prostate cancers, however this is our first experience of treating anal cancer with brachytherapy. We present a case study of a patient with localised primary anal cancer that was referred to our department to determine if brachytherapy would be an option. This 80yr old fit/independent female had adjuvant pelvic radiation treatment for a cervical cancer (Stage 1B) SCC in 1981 receiving a dose of 45Gy/20#. She was recently diagnosed with SCC of Anal Canal (cT1 N0) and further curative external beam radiation was deemed too high risk in terms of toxicities and morbidities and patient was reluctant to accept abdominoperineal resection for reasons relating to quality of life when dealing with a permanent stoma. Even though there is not much evidence for using brachytherapy as a sole modality for curative treatment for anal cancer, given the limited treatment options available, this would not be an unreasonable approach. Staging Colonoscopy, FDG PET CT scan, and MRI highlighted a superficial tumour that extended a total of 16mm from proximal anal canal to mid anal canal from 12-7 o'clock position without invasion or lymphadenopathy. A pre-BT MRI was performed with the Nucletron Multichannel applicator (MCA) in situ. The plan was optimised in Oncentra Brachy (OCB) V4.6.2 using a combination of central channel and superficial channels. A prescription dose of 33Gy/6# was chosen and the final dose coverage of the targets are listed below: Dose reporting for targets: Dose per fraction / Dose per treatment EQD2Gy (a/b =10) HRCTV: D90= 5.8Gy/ 45.4Gy D100= 5.3Gy / 41.0Gy IRCTV: D90= 4.8Gy / 35.6Gy D100= 4.2Gy / 29.9Gy Following completion of BT, patient developed radiation dermatitis with some soreness around the perianal area that was treated with local suppositories and hydrocortisone cream. At 3 and 6 months follow-up, there was no signs of active dermatitis or any bowel incontinence Brachytherapy (BT) has been utilized for the treatment of anal cancer for many decades. A previous systematic review had shown benefit of BT boost in patients undergoing curative intent chemo-radiotherapy for anal canal cancer. Despite this, the use of BT boost is still restricted to a few ","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135434393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PO91","authors":"Sophia Rooks, Reza Taleei, Nicole Simone, P. Rani Anne, Firas Mourtada","doi":"10.1016/j.brachy.2023.06.192","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.192","url":null,"abstract":"Purpose To commission and retrospectively compare dosimetry of Elekta's Advanced Collapsed Cone Engine (ACE) calculation algorithm with the standard TG 43-based dose formalism on an IPSA-optimized and CT-based HDR clinical breast plan. Materials and Methods At our institution, we commissioned ACE for HDR brachytherapy using the “Breast Test Case” data from iroc.mdandderson.org. This used a generic Ir-192 source and was published by the AAPM Working Group on Commissioning of Model-Based Dose Calculation Algorithms in Brachytherapy (UN35). A previous breast cancer case treated with Hologic's Contura multi-catheter HDR applicator was selected from our clinical database to evaluate the ACE dose engine. The Oncentra treatment planning system (v. 4.6) was used in this study. The HDR plan was first calculated with the TG-43 dose formalism and optimized using inverse planning by a simulated annealing algorithm (IPSA). Using the same relative dwell weights provided by IPSA from the TG-43 plan, dose was then recalculated using the ACE algorithm. The ACE calculation used Oncentra's High Accuracy level with a 1.0-mm-cubed dose grid. The planning target volume (PTV) and organs at risk (including regions with significant inhomogeneity) were contoured. Dose Volume Histograms (DVH's) of the PTV_eval and organs at risk were calculated with both TG-43 and ACE dose formalisms for each plan. Absolute and percent differences were also calculated for each metric. Results As shown in Table 1, the ACE calculated dose relative to the TG-43 calculated dose is consistently lower for all dosimetric parameters. The dose calculation differed by up to 9% or 112 cGy in the selected parameters. See comparison table for more details. The calculation time was 16 minutes using the standard GPU provided by Elekta hardware. Conclusion The IROC “Breast Test Case” ACE commissioning was a straightforward procedure and easy installation. Total commissioning time was less than an hour. The ACE calculated dose relative to the TG-43 calculated dose in the selected patient case was consistently lower for all dosimetric parameters. This algorithm offers a more accurate reconstruction of the dose distribution (by comparison to Monte Carlo, per UN35). The highest percent differences in dose calculation were found in the PTV_eval and skin region for this case. This study provides a framework for future studies of ACE dosimetric impact for breast cancer brachytherapy, and more breast cancer patient plans will be analyzed with summary statistics reported. This will be a particularly useful framework when correlating lower skin dose estimate with cosmetic outcomes. To commission and retrospectively compare dosimetry of Elekta's Advanced Collapsed Cone Engine (ACE) calculation algorithm with the standard TG 43-based dose formalism on an IPSA-optimized and CT-based HDR clinical breast plan. At our institution, we commissioned ACE for HDR brachytherapy using the “Breast Test Case” data from iroc.mdand","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135434412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PO64","authors":"Shyamal Patel, Dilini Pinnaduwage, Nitika Thawani, Stephen Sorensen, Shyam Jani, Steven Ellefson, Aidnag Diaz, Shiv Srivastava","doi":"10.1016/j.brachy.2023.06.165","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.165","url":null,"abstract":"Purpose When utilizing a hydrogel spacer for HDR prostate brachytherapy, hydrogel can be inserted at time of HDR catheter implantation or on a separate visit prior to HDR. The insertion of gel at time of HDR can be more difficult due to interference from the perineal template with imbedded catheters. To assess whether time of hydrogel placement impacted its insertion geometry, we compared patients who had hydrogel placed by a single provider at either the time of HDR brachytherapy (templated insertion - TI) or in advance of prostate stereotactic body radiation therapy (non-templated insertion - NTI). The ultimate aim of this study was to determine whether patients undergoing HDR should have hydrogel placed prior to catheter implantation for improved rectal dosimetry. Materials and Methods The last consecutive 25 patients treated with HDR brachytherapy with hydrogel (TI) and the last consecutive 25 patients treated with prostate SBRT with hydrogel (NTI) in 2022 were included for analysis. CT planning scans for all patients were reviewed and insertion geometry was recorded as represented by measurements of the anteroposterior rectoprostatic separation at the gland apex, mid, and base. Prostate clinical target volume (CTV) measurements for all patients were recorded. Additionally, rectal D0.1cc, D1cc, and D2cc measurements were also noted for the 25 HDR TI patients. Data were analyzed using a one-way MANOVA to determine significance of templated insertion. Subsequently multiple regression analyses were performed to evaluate the impact of insertion geometry and CTV measurements on rectal dosimetry. Results The differences in AP separations between TI and NTI were nonsignificant. The mean TI and NTI separations (cm) were 1.08 vs. 1.18 for apex, p=0.40; 1.40 vs. 1.42 for mid, p=0.84; and 1.52 vs. 1.47 for base, p=0.77. In HDR patients with templated insertion, AP separations at the apex and mid gland were significant in predicting rectal D0.1cc (β -0.49 and -0.51, p<0.001), D1cc (β -0.46 and -0.56, p<0.001) and D2cc (β -0.45 and -0.55, p<0.001). The base separations were not significant. CTVs also did not significantly predict for rectal dosimetry. Conclusions Placement of hydrogel spacer at time of HDR brachytherapy does not appear to adversely affect hydrogel insertion geometry and consequently rectal dosimetry when compared to placement in advance. We will continue our practice of inserting hydrogel at time of HDR brachytherapy as this method is efficient and also more convenient for patients. When utilizing a hydrogel spacer for HDR prostate brachytherapy, hydrogel can be inserted at time of HDR catheter implantation or on a separate visit prior to HDR. The insertion of gel at time of HDR can be more difficult due to interference from the perineal template with imbedded catheters. To assess whether time of hydrogel placement impacted its insertion geometry, we compared patients who had hydrogel placed by a single provider at either the time of HDR ","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135434417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PO114","authors":"Evangelia Kaza, Phillip M. Devlin, Ivan Buzurovic","doi":"10.1016/j.brachy.2023.06.215","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.215","url":null,"abstract":"","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135434420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}