Brachytherapy最新文献

{"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}

{"title":"PO12","authors":"Ke Xu","doi":"10.1016/j.brachy.2023.06.113","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.113","url":null,"abstract":"","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"69 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":"135434436","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":"PO109","authors":"Juan Wang, Guohui Cao","doi":"10.1016/j.brachy.2023.06.210","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.210","url":null,"abstract":"","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"15 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":"135434513","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":"PO60","authors":"Kevin Martell, Breanna Fang, Philip McGeachy, Tyler Meyer, Siraj Husain, Kundan Thind","doi":"10.1016/j.brachy.2023.06.161","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.161","url":null,"abstract":"Purpose Isolated intraprostatic recurrence of prostate adenocarcinoma post radiotherapy presents a clinically challenging situation as surgical salvage options are associated with high morbidity. Brachytherapy can be used in these cases but supportive data are limited. The present study aims to present the acute toxicity results from patients who received salvage high-dose-rate prostate brachytherapy (sHDR-BT) for intraprostatic recurrence of prostate adenocarcinoma. Materials and Methods Fourteen consecutive patients treated with sHDR-BT between 2019 and 2022 were prospectively evaluated. To be considered for sHDR-BT, patients were required to have had received curative intent prostate radiotherapy previously and have biochemical failure. Patients were evaluated with bone scan and CT imaging of the chest abdomen and pelvis or PSMA-PET imaging. All patients had MRI of the prostate and trans-rectal ultrasound (US) guided biopsy proven confirmation of intraprostatic recurrence of disease. For patients who received prior BT, sHDR-BT was standardized with prescribed dose of 27Gy in 2 fractions to prostatic regions with confirmed disease on MR or biopsy. For patients had no history of prior BT, sHDR-BT was standardized with a prescribed dose of 21Gy in 2 fractions to the entire prostate with integrated boost irradiation of 27Gy in 2 fractions to the prostatic zones with confirmed disease on MR or biopsy. All plans were designed using trans-rectally acquired US image sets in Oncentra Prostate®. Post-treatment monitoring consisted of either in person or telephone (due to COVID-19) evaluation with AUA and CTCAE symptom assessments at 1, 3 and 12 months post treatment and yearly thereafter. Descriptive statistics were used to describe outcomes and the Mann-Whitney-Wilcoxon or Fisher-Freeman-Halton test used for comparisons. Results Median (inter-quartile-range) age prior to salvage treatment was 72 (67-76) years for the cohort. Seven (50%) patients had received external beam radiotherapy (EBRT) monotherapy (74-78Gy) as initial treatment for prostate cancer. One (7%) received EBRT (46Gy) + low-dose-rate BT (LDR-BT) (110Gy) and six (43%) received LDR-BT (144Gy) monotherapy as initial treatment. Four (29%) had received elective nodal irradiation (46Gy) with EBRT. Median time from initial radiotherapy to biopsy confirmation of recurrent disease was 77 (54-111) months. At baseline prior to sHDR-BT, 7 (50%) patient had significant lower urinary tract symptoms. Median AUA score was 8 (3-20) prior to sHDR-BT [Table 1]. 3 (21%) patients reported irregular bowel function and 2 (14%) reported hematochezia prior to sHDR-BT. At first fraction of sHDR-BT rectal D100cc was 8 (6-9)Gy, urethra D10% was 12 (11-15)Gy, urethra Dmax was 15 (13-16)Gy. At second fraction of sHDR-BT rectal D100cc was 8 (7-9)Gy, urethra D10% was 12 (12-14)Gy and urethra Dmax was 13 (12-16)Gy. At 1-month post treatment, median AUA score was 13 (18-21; p=0.48). On review of CTCAE scoring, at 1-mont","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"69 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":"135434527","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":"Miscellaneous Posters PO101","authors":"Melisa Pasli, Sara Cowles, Jasmin Jo, Mahmoud Yaqoub, Hilal A. Kanaan, Andrew Ju, Matthew Sean Peach","doi":"10.1016/j.brachy.2023.06.202","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.202","url":null,"abstract":"Purpose Controversy exists regarding radiotherapy of patients with connective tissue disorders due to increased radiosensitivity. GammaTile® (GT Medical Technologies, Tempe, Arizona) is a novel brachytherapy strategy for intracranial radiotherapy. The suspension of the seeds in this matrix results in more uniformed dose delivery throughout the periphery of resection cavities, potentially reducing necrosis risk and conserving surrounding brain parenchyma. We hypothesized that GammaTile® would result in decreased dose to the scalp and incision wound in a patient with a Grade 3 glioma and limited scleroderma with active disease in the overlying scalp. Materials and Methods Preoperative MRI was used to estimate the number of tiles needed to deliver 60 Gy to a 5mm depth from the resection cavity. The tiles were placed after a right frontotemporal craniotomy with maximal safe resection. Day 1 post-implant dosimetry was performed with MRI and CT utilizing MIM to contour the sources and planning target volume (PTV); a 5mm expansion from the surgical cavity along tumor involved surfaces. A hypothetical standard external beam (EBRT) plan was generated in Eclipse with a 1cm expansion from the cavity and a 5mm expansion to PTV. A similar volume to GammaTile was generated using the CybrerKnife planning system with a 5 mm expansion of the cavity to PTV. Both plans were dosed to 59.3 Gy in 33 fractions to 95% coverage. All dose clouds were imported into Velocity and converted to equivalent dose in 2Gy (EQD2). Organs at risk (OARs) including the scalp and incision scar were contoured and dose volume histograms (DHVs) generated in Velocity. The patient underwent physical exam at 1, 3, and 6 months and MRI brain at 3 and 6 months, with photo documentation of the scalp. Results A total of 10 tiles were ordered and ultimately used with no tiles split to cover a 39.76 cc resection cavity as indicated on Day 1 post implant imaging. The resulting PTV was 31.18 cc with the V100% (60 Gy) of 99% and D90 of 118.7%. Compared to the GammaTile dose cloud, those generated by both EBRT plans resulted in greater irradiation to the surgical scar (Figure 1A-C, green line). Figure 1D-F shows the DVH between GammaTile (green), standard EBRT (red) and CybrerKnife (blue) for the scar, scalp and normal brain parenchyma. Overall, there was significant reduction in dose to these OARs with GammaTile. In particular, the maximum dose delivered to the scar and scalp by GammaTile was reduced to half of that from other external beam techniques (∼25-30 Gy vs ∼55 Gy). MRI imaging at 3 and 6 months lacked evidence of disease recurrence or radionecrosis. At the 6 month follow up visit, the surgical scar was well healed and there were no skin changes to the surrounding scalp at any time during follow up. Conclusions Compared to EBRT techniques, GammaTile brachytherapy is able to deliver considerably less dose to the scalp and scar incision in a Grade 3 glioma patient with limited scleroderma and ac","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"104 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":"135434599","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":"PO41","authors":"Palanikumar Gunasekar, Susan Mathews, Francis V. James, Aswin Kumar, John Joseph, Sharika V. Menon, K.M. Jagathnath Krishna","doi":"10.1016/j.brachy.2023.06.142","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.142","url":null,"abstract":"Purpose Cervical cancer is the second most common cancer among Indian women. Radical chemo-radiotherapy is the standard of care for the majority of patients in India since most patients get diagnosed late and have locally advanced disease. Traditional Manchester system based brachytherapy planning and dose delivery continues to be widely practiced. Cervical cancer with disease extension beyond upper vagina presents a unique problem for brachytherapy dose delivery. Ovoid in tandem in the vagina is considered ‘Non-standard application’ in the traditional Manchester system where a lower dose to ‘Point A’ is accepted respecting the tolerances. Even in the era of image based brachytherapy, the number and position of the source channels limit the extent of dose optimization possible within the various normal tissue tolerances. The Rotterdam applicator, with both Ovoids and vaginal cylinder, offers the possibility of improved dose delivery in this group of patients. The potential dosimetric advantage was tested in this study. Methods Consecutive cervical cancer patients with vaginal disease beyond mid vagina at presentation were selected for Rotterdam Application. All patients had MR imaging in addition to standard CT planning. High Risk target volume (HRCTV) and organs at risk (OAR) were contoured on MR images as per the GEC-ESTRO guidelines and dose optimized plans were generated on Oncentra planning system V4.6. Residual disease in the vagina was part of the HRCTV and the length of vagina to be treated (tandem vaginal loading) was decided by the extent of initial disease involvement. The prescription dose was 8 Gy and dose constraints to OARs were (≤6 Gy/fx) to rectal D2cc and (≤7.5 Gy/fx) to the bladder D2cc (Subir Nag HDR BT dosimetry data). Two sets of treatment plans were generated for each application 1) with central tandem loading only (IUT PLAN) and 2) Rotterdam plan where ovoids were loaded in addition to central tandem. The HRCTV D90, D2cc Bladder, D2cc Rectum were documented and compared between the two plans. Data was analyzed statistically using paired t-test (normally distributed) or Wilcoxon signed rank test (Non-normal). A p-value < 0.05 is considered to be statistically significant. Results Between 1st January 2021 and 30th June 2022, 24 patients were eligible for Rotterdam application. However, applicator placement was not feasible in 6 patients (25%) with severe upper vaginal narrowing. MR image based plans were generated for 31 applications. The mean age of the patients included in the study was 59 years. Stage wise distribution was as follows IIB-3, IIIB-4, IIIC1-4, IIIC2-2, & IVA-5. At the time of brachytherapy, 10 patients had minimal residual disease involving cervix and upper vagina. None of the patients had residual disease involving lower vagina. The mean HRCTV volume was 30cc (range- 14.29 cc- 51.92cc). The prescription goal of 8Gy or greater was achieved in 18 Rotterdam applications while with standard loading, 12 applicat","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"18 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":"135434600","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}