Pub Date : 2023-09-01DOI: 10.1016/j.brachy.2023.06.216
Miren Gaztañaga, Virginia Álvarez, Javier De Areba, Saadia Tremolada, Pino Alcántara, Elena Cerezo, Juan Antonio Corona, Anxela Doval, Fernando Puebla, Noelia Sanmamed, Manuel Gonzalo Vázquez
Purpose Perioperative accelerated partial breast irradiation with multicatheter interstitial brachytherapy is an alternative to the postoperative option that offers advantages in terms of specificity and comfort for patients as it avoids a second procedure. Since the simulation CT scan is performed 48 hours after the intervention, immediate tissue changes as air gaps can occasionally be observed. To our knowledge, there is no literature published on this regard, so the aim of this study was to assess the impact of significant air gaps when planning and treating multicatheter perioperative breast cancer brachytherapy. Methods and Materials Two consecutive cases with air gaps > 6 cc were included. For each case, a planning CT scan was performed 48 hours after the surgical procedure (tumorectomy + catheter insertion). Treatment planning was performed according to the department protocol and administered in an ultra-fractionated scheme: 3 fractions of 745 cGy every 12 hours. A second CT scan was performed right after the last treatment fraction, before the catheter removal. The air gaps have been contoured in both pre and post-treatment CTs and their volumes have been compared. The scans have been fused and the dosimetric differences have been evaluated. A total of 13 catheters have been analyzed in both scans. Results A volume reduction (-10% and -30% for each case) has been observed in the post-treatment air gap. Of the 13 catheters compared in the CT scans fusion, the catheter position displacement inside CTV was ≤ 1.5 mm in 12 of them (median displacement 1 mm), with one catheter displaced 2.7 mm in the post-treatment CT. Mean CTVD90 and V100 variation in the pre and post-treatment scans were -1.5 and -1.7% respectively. Dose variations in surrounding organs were: Skin Dmax -10 and -3%, Ribs Dmax +15 and +15% and Ipsilateral Lung Dmax +12 and +13%. Dosimetric disparities did not exceed tolerance and coverage limits in any case. Conclusions With two cases analyzed, the volumetric reduction of the air gaps does not seem to affect the geometry of the implants, with most of the catheters remaining stable in their initial position. Discrete changes in the coverage parameters and doses to OARs fulfill the pre-established constraints. The confirmation of these results as well as the clinical relevance of these changes has to be examined in future studies including more patients. Perioperative accelerated partial breast irradiation with multicatheter interstitial brachytherapy is an alternative to the postoperative option that offers advantages in terms of specificity and comfort for patients as it avoids a second procedure. Since the simulation CT scan is performed 48 hours after the intervention, immediate tissue changes as air gaps can occasionally be observed. To our knowledge, there is no literature published on this regard, so the aim of this study was to assess the impact of significant air gaps when planning and treating multicatheter perioperati
{"title":"PO115","authors":"Miren Gaztañaga, Virginia Álvarez, Javier De Areba, Saadia Tremolada, Pino Alcántara, Elena Cerezo, Juan Antonio Corona, Anxela Doval, Fernando Puebla, Noelia Sanmamed, Manuel Gonzalo Vázquez","doi":"10.1016/j.brachy.2023.06.216","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.216","url":null,"abstract":"Purpose Perioperative accelerated partial breast irradiation with multicatheter interstitial brachytherapy is an alternative to the postoperative option that offers advantages in terms of specificity and comfort for patients as it avoids a second procedure. Since the simulation CT scan is performed 48 hours after the intervention, immediate tissue changes as air gaps can occasionally be observed. To our knowledge, there is no literature published on this regard, so the aim of this study was to assess the impact of significant air gaps when planning and treating multicatheter perioperative breast cancer brachytherapy. Methods and Materials Two consecutive cases with air gaps > 6 cc were included. For each case, a planning CT scan was performed 48 hours after the surgical procedure (tumorectomy + catheter insertion). Treatment planning was performed according to the department protocol and administered in an ultra-fractionated scheme: 3 fractions of 745 cGy every 12 hours. A second CT scan was performed right after the last treatment fraction, before the catheter removal. The air gaps have been contoured in both pre and post-treatment CTs and their volumes have been compared. The scans have been fused and the dosimetric differences have been evaluated. A total of 13 catheters have been analyzed in both scans. Results A volume reduction (-10% and -30% for each case) has been observed in the post-treatment air gap. Of the 13 catheters compared in the CT scans fusion, the catheter position displacement inside CTV was ≤ 1.5 mm in 12 of them (median displacement 1 mm), with one catheter displaced 2.7 mm in the post-treatment CT. Mean CTVD90 and V100 variation in the pre and post-treatment scans were -1.5 and -1.7% respectively. Dose variations in surrounding organs were: Skin Dmax -10 and -3%, Ribs Dmax +15 and +15% and Ipsilateral Lung Dmax +12 and +13%. Dosimetric disparities did not exceed tolerance and coverage limits in any case. Conclusions With two cases analyzed, the volumetric reduction of the air gaps does not seem to affect the geometry of the implants, with most of the catheters remaining stable in their initial position. Discrete changes in the coverage parameters and doses to OARs fulfill the pre-established constraints. The confirmation of these results as well as the clinical relevance of these changes has to be examined in future studies including more patients. Perioperative accelerated partial breast irradiation with multicatheter interstitial brachytherapy is an alternative to the postoperative option that offers advantages in terms of specificity and comfort for patients as it avoids a second procedure. Since the simulation CT scan is performed 48 hours after the intervention, immediate tissue changes as air gaps can occasionally be observed. To our knowledge, there is no literature published on this regard, so the aim of this study was to assess the impact of significant air gaps when planning and treating multicatheter perioperati","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"106 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":"135434426","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}
Pub Date : 2023-09-01DOI: 10.1016/j.brachy.2023.06.151
Michael Jason Gutman, Tianming Wu, Christina Son, Hania Al-Hallaq, Yasmin Hasan
Purpose Triple tandem brachytherapy (TTB) provides superior coverage of the uterus and minimizes dose to OARs compared to single or dual tandem therapy, per prior dosimetric analysis of 3 representative cases (1). We report the technical feasibility and dosimetry of TTB in a cohort of patients with medically inoperable endometrial cancer (EC). Materials and Methods An IRB approved retrospective review was performed of all medically inoperable EC patients treated definitively with TTB ± external beam radiotherapy (EBRT) between 2014-2021 at a single institution (n=30). Patients underwent off-line MRI which was fused for planning (n=24, 80%) and all underwent intraoperative transabdominal ultrasound for dilation and device placement. Patients had FIGO stage 1a-4b disease; patients with ≥ stage 2 disease received TTB +/- ovoids. Kaplan-Meier estimates were generated to estimate local failure-free survival (LFFS). The equivalent dose in 2-Gy fractions (EQD2) constraints for dose to 2cc (D2cc) of the bladder, rectum, and bowel were <90Gy, <75Gy, and <65Gy, respectively, per ABS guidelines. The cumulative D90% (minimum dose to 90% of volume) in EQD2 was calculated for GTV and CTV and the organs at risk (OAR) for each patient. Statistics reported are median values and ranges. The dwell time contribution from each tandem was collected. Results Of 30 patients, 93.3% received EBRT and TTB. Mean age at time of diagnosis was 65.3 years (range: 40.5-88.7 years). The median BMI was 48.1 (range: 27.8-69). The median prescribed doses were 45 Gy (range: 21-50.4 Gy) for EBRT and 22.25 Gy in 5 fractions (range: 16.5-49.1 Gy) for brachytherapy. The median cumulative EQD2 to the GTV was 78.6 Gy (range: 67.8- 86.6) and to the CTV was 67.6 Gy (range: 48- 79.8), of which the TTB contributed a median EQD2 of 33.8 Gy and 23.3 Gy to the GTV and CTV, respectively. The central tandem was not placed for 4 patients (13.3%) due to concern for posterior cervix and/or posterior uterine wall perforation. In the entire cohort, the central tandem contributed at least 10% and 15% of the dwell time in 77% (n=23) and 60% (n=18) of patients, respectively (Figure 1). In one third of patients, the central tandem contributed ≥30% of the dwell time. The lateral tandems contributed the majority (82%, range: 32-100%) of total dwells. Median follow up was 32.1 months (1.7-93.6 months). Kaplan-Meier-estimated 1-/5-yr LFFS was 96.2%/84.1%. The cumulative D2cc: 71.0Gy (range: 25.2-91.2Gy) to the bladder, 53.6Gy (range: 25.2-76.2Gy) to the rectum, and 58.1Gy (range: 14.1-72Gy) to the small bowel. No procedure-related perforation, bleeding or acute complication occurred intra- or post-operatively. Conclusions TTB + EBRT for inoperable EC patients was safe and acceptable target coverage was achieved in most cases. While posterior/central tandem insertion may not be feasible for all patients in our experience, this limitation was not prohibitive to adequate dose distribution and local control. Furthe
{"title":"PO50","authors":"Michael Jason Gutman, Tianming Wu, Christina Son, Hania Al-Hallaq, Yasmin Hasan","doi":"10.1016/j.brachy.2023.06.151","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.151","url":null,"abstract":"Purpose Triple tandem brachytherapy (TTB) provides superior coverage of the uterus and minimizes dose to OARs compared to single or dual tandem therapy, per prior dosimetric analysis of 3 representative cases (1). We report the technical feasibility and dosimetry of TTB in a cohort of patients with medically inoperable endometrial cancer (EC). Materials and Methods An IRB approved retrospective review was performed of all medically inoperable EC patients treated definitively with TTB ± external beam radiotherapy (EBRT) between 2014-2021 at a single institution (n=30). Patients underwent off-line MRI which was fused for planning (n=24, 80%) and all underwent intraoperative transabdominal ultrasound for dilation and device placement. Patients had FIGO stage 1a-4b disease; patients with ≥ stage 2 disease received TTB +/- ovoids. Kaplan-Meier estimates were generated to estimate local failure-free survival (LFFS). The equivalent dose in 2-Gy fractions (EQD2) constraints for dose to 2cc (D2cc) of the bladder, rectum, and bowel were <90Gy, <75Gy, and <65Gy, respectively, per ABS guidelines. The cumulative D90% (minimum dose to 90% of volume) in EQD2 was calculated for GTV and CTV and the organs at risk (OAR) for each patient. Statistics reported are median values and ranges. The dwell time contribution from each tandem was collected. Results Of 30 patients, 93.3% received EBRT and TTB. Mean age at time of diagnosis was 65.3 years (range: 40.5-88.7 years). The median BMI was 48.1 (range: 27.8-69). The median prescribed doses were 45 Gy (range: 21-50.4 Gy) for EBRT and 22.25 Gy in 5 fractions (range: 16.5-49.1 Gy) for brachytherapy. The median cumulative EQD2 to the GTV was 78.6 Gy (range: 67.8- 86.6) and to the CTV was 67.6 Gy (range: 48- 79.8), of which the TTB contributed a median EQD2 of 33.8 Gy and 23.3 Gy to the GTV and CTV, respectively. The central tandem was not placed for 4 patients (13.3%) due to concern for posterior cervix and/or posterior uterine wall perforation. In the entire cohort, the central tandem contributed at least 10% and 15% of the dwell time in 77% (n=23) and 60% (n=18) of patients, respectively (Figure 1). In one third of patients, the central tandem contributed ≥30% of the dwell time. The lateral tandems contributed the majority (82%, range: 32-100%) of total dwells. Median follow up was 32.1 months (1.7-93.6 months). Kaplan-Meier-estimated 1-/5-yr LFFS was 96.2%/84.1%. The cumulative D2cc: 71.0Gy (range: 25.2-91.2Gy) to the bladder, 53.6Gy (range: 25.2-76.2Gy) to the rectum, and 58.1Gy (range: 14.1-72Gy) to the small bowel. No procedure-related perforation, bleeding or acute complication occurred intra- or post-operatively. Conclusions TTB + EBRT for inoperable EC patients was safe and acceptable target coverage was achieved in most cases. While posterior/central tandem insertion may not be feasible for all patients in our experience, this limitation was not prohibitive to adequate dose distribution and local control. Furthe","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":"135434430","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}
Pub Date : 2023-09-01DOI: 10.1016/j.brachy.2023.06.172
Hong Zhang, Catherine Liu
Purpose High-Dose-Rate Brachytherapy (HDR-BT) is an effective yet under-utilized treatment option for localized prostate cancer. Many studies have shown excellent long-term biochemical-failure-free survival outcomes with limited toxicity from HDR-BT as monotherapy for low- or intermediate-risk prostate cancer. However, due to higher start-up costs, less reimbursement, and inadequacy in residency training, far fewer radiation facilities are offering BT than external beam radiation (EBRT). Here, we performed a single-center, retrospective cohort study to evaluate the travel burdens put on patients who received BT as monotherapy at our high-volume center and if they had chosen external beam radiation close to home for localized prostate cancer. Materials and Methods From 1/1/2019 to 12/31/2022, 69 men were treated with HDR-BT as monotherapy at our brachytherapy center, receiving 27 Gy in 2 fractions, one week apart. Sixty-eight men had low- or intermediate-risk prostate cancer (Table). The travel burden for HDR-BT as monotherapy was estimated by collecting the distance between each patient's home address to our BT center (BT-D). The distance between each patient's home address and the nearest EBRT facility (EBRT-D) was also collected. The total travel burden for EBRT was then calculated, assuming a standard regiment of 28 fractions was used. Results Of the 69 patients who received BT for prostate cancer, the average age was 67.9 years, the overwhelming majority were white (96%), and all had insurance. The median and average EBRT-D were 5.5 and 8.3 miles, respectively. The median and average BT-D were 21 and 37.4 miles, respectively. However, due to the fewer visits required for BT (2 versus 28 trips), the total BT travel burden (median 84 miles, average 150.0 miles) was significantly less than for these patients if they had chosen EBRT instead (median 308 miles, average 462.5 miles) (p<0.01). On average, by choosing BT instead of EBRT, these patients reduced their travel burden by 312.5 miles. Conclusions We observed a significantly decreased overall travel burden for HDR-BT as monotherapy compared with EBRT in our cohort of patients with localized prostate cancer, despite a longer travel distance to our BT center than a nearby EBRT facility. Our study supports that HDR-BT as monotherapy remains a practical and preferred option for patients with localized prostate cancer, not only for its proven safety and efficacy but also decreased overall travel burden compared with definitive EBRT therapy. High-Dose-Rate Brachytherapy (HDR-BT) is an effective yet under-utilized treatment option for localized prostate cancer. Many studies have shown excellent long-term biochemical-failure-free survival outcomes with limited toxicity from HDR-BT as monotherapy for low- or intermediate-risk prostate cancer. However, due to higher start-up costs, less reimbursement, and inadequacy in residency training, far fewer radiation facilities are offering BT than external be
{"title":"PO71","authors":"Hong Zhang, Catherine Liu","doi":"10.1016/j.brachy.2023.06.172","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.172","url":null,"abstract":"Purpose High-Dose-Rate Brachytherapy (HDR-BT) is an effective yet under-utilized treatment option for localized prostate cancer. Many studies have shown excellent long-term biochemical-failure-free survival outcomes with limited toxicity from HDR-BT as monotherapy for low- or intermediate-risk prostate cancer. However, due to higher start-up costs, less reimbursement, and inadequacy in residency training, far fewer radiation facilities are offering BT than external beam radiation (EBRT). Here, we performed a single-center, retrospective cohort study to evaluate the travel burdens put on patients who received BT as monotherapy at our high-volume center and if they had chosen external beam radiation close to home for localized prostate cancer. Materials and Methods From 1/1/2019 to 12/31/2022, 69 men were treated with HDR-BT as monotherapy at our brachytherapy center, receiving 27 Gy in 2 fractions, one week apart. Sixty-eight men had low- or intermediate-risk prostate cancer (Table). The travel burden for HDR-BT as monotherapy was estimated by collecting the distance between each patient's home address to our BT center (BT-D). The distance between each patient's home address and the nearest EBRT facility (EBRT-D) was also collected. The total travel burden for EBRT was then calculated, assuming a standard regiment of 28 fractions was used. Results Of the 69 patients who received BT for prostate cancer, the average age was 67.9 years, the overwhelming majority were white (96%), and all had insurance. The median and average EBRT-D were 5.5 and 8.3 miles, respectively. The median and average BT-D were 21 and 37.4 miles, respectively. However, due to the fewer visits required for BT (2 versus 28 trips), the total BT travel burden (median 84 miles, average 150.0 miles) was significantly less than for these patients if they had chosen EBRT instead (median 308 miles, average 462.5 miles) (p<0.01). On average, by choosing BT instead of EBRT, these patients reduced their travel burden by 312.5 miles. Conclusions We observed a significantly decreased overall travel burden for HDR-BT as monotherapy compared with EBRT in our cohort of patients with localized prostate cancer, despite a longer travel distance to our BT center than a nearby EBRT facility. Our study supports that HDR-BT as monotherapy remains a practical and preferred option for patients with localized prostate cancer, not only for its proven safety and efficacy but also decreased overall travel burden compared with definitive EBRT therapy. High-Dose-Rate Brachytherapy (HDR-BT) is an effective yet under-utilized treatment option for localized prostate cancer. Many studies have shown excellent long-term biochemical-failure-free survival outcomes with limited toxicity from HDR-BT as monotherapy for low- or intermediate-risk prostate cancer. However, due to higher start-up costs, less reimbursement, and inadequacy in residency training, far fewer radiation facilities are offering BT than external be","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"107 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":"135434441","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}
Pub Date : 2023-09-01DOI: 10.1016/j.brachy.2023.06.136
Suman Gautam, Alexander F. I Osman, Dylan Richerson, Binod Manandhar, Sharmin Alam, William Y. Song
Purpose The purpose of this work is to develop a voxel-wise dose prediction system using convolutional neural network (CNN) for cervical cancer high-dose-rate (HDR) intracavitary brachytherapy treatment planning with tandem-and-ovoid (T&O) or tandem-and-ring (T&R) applicators. Materials and Methods A 3D U-NET CNN was implemented to generate voxel-wise dose predictions based on high-risk clinical target volume (HRCTV) and organs at risk (OAR) contour information. A multi-institutional cohort of 77 retrospective clinical HDR brachytherapy plans treated to a prescription dose in the range of 4.8-7.0 Gy/fx was used in this study. Those plans were randomly divided into 60%/20%/20% as training, validating, and testing cohorts. Data augmentation techniques like flip diagonally, flip left and right, flipping up and down, and rotating 90 degrees were implemented in the training and validation cohort data to increase the number of plans to 252. The model was trained using the mean-squared loss function, Adam optimization algorithm, a learning rate of 0.001, 250 epochs, and a batch size of 8. The model performance was evaluated on the testing dataset by analyzing the outcomes in terms of maximum dose values and derived dose-volume-histogram (DVH) indices from 3D dose distributions and comparing the generated dose distributions against the ground-truth dose distributions using dose statistics and clinically meaningful dosimetric indices. Results The proposed 3D U-Net model showed competitive accuracy in predicting 3D dose distributions that closely resemble the ground truth dose distributions. The average value of mean absolute error was 0.108±3.617 Gy for HRCTV, 0.074±1.315 Gy for bladder, 0.093±0.981 Gy for rectum, and 0.035±2.789 Gy for sigmoid. The median absolute error was 0.126 Gy for HRCTV, 0.041 Gy for the bladder, 0.0013 Gy for rectum, and 0.019 Gy for sigmoid. Our results showed that the predicted mean D2cc OAR doses in the bladder, rectum, sigmoid were 3.51±1.25, 3.11±1.23 and 4.02±2.23 Gy in comparison to 4.21±1.23, 4.20±1.02, 4.80±1.59 Gy in clinical plans respectively. The predicted D90 of the HRCTV was 6.72±0.99 Gy in comparison with 6.83±1.72 Gy in clinical plans. The predicted maximum dose to bladder, sigmoid, and rectum were 7.51±1.10, 3.81±1.27, 3.61±1.16 Gy in comparison to 7.33±1.03, 4.66±2.06, 4.33±1.75 Gy in clinical plans, respectively, indicating a good potential to predict useful dosimetric indices and facilitate an improvement in brachytherapy treatment workflow. The proposed model needs less than 5 seconds to predict a full 3D dose distribution of 64 × 64 × 64 voxels for any new patient plan, thus making it sufficient for near real-time applications and aid in decision-making in clinic. Conclusions The 3D U-Net model we have implemented demonstrates competitive capability in predicting accurate dose distributions and DVH indices with consistent quality. The proposed model can be used to predict 3D dose distributions for near real-
{"title":"PO35","authors":"Suman Gautam, Alexander F. I Osman, Dylan Richerson, Binod Manandhar, Sharmin Alam, William Y. Song","doi":"10.1016/j.brachy.2023.06.136","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.136","url":null,"abstract":"Purpose The purpose of this work is to develop a voxel-wise dose prediction system using convolutional neural network (CNN) for cervical cancer high-dose-rate (HDR) intracavitary brachytherapy treatment planning with tandem-and-ovoid (T&O) or tandem-and-ring (T&R) applicators. Materials and Methods A 3D U-NET CNN was implemented to generate voxel-wise dose predictions based on high-risk clinical target volume (HRCTV) and organs at risk (OAR) contour information. A multi-institutional cohort of 77 retrospective clinical HDR brachytherapy plans treated to a prescription dose in the range of 4.8-7.0 Gy/fx was used in this study. Those plans were randomly divided into 60%/20%/20% as training, validating, and testing cohorts. Data augmentation techniques like flip diagonally, flip left and right, flipping up and down, and rotating 90 degrees were implemented in the training and validation cohort data to increase the number of plans to 252. The model was trained using the mean-squared loss function, Adam optimization algorithm, a learning rate of 0.001, 250 epochs, and a batch size of 8. The model performance was evaluated on the testing dataset by analyzing the outcomes in terms of maximum dose values and derived dose-volume-histogram (DVH) indices from 3D dose distributions and comparing the generated dose distributions against the ground-truth dose distributions using dose statistics and clinically meaningful dosimetric indices. Results The proposed 3D U-Net model showed competitive accuracy in predicting 3D dose distributions that closely resemble the ground truth dose distributions. The average value of mean absolute error was 0.108±3.617 Gy for HRCTV, 0.074±1.315 Gy for bladder, 0.093±0.981 Gy for rectum, and 0.035±2.789 Gy for sigmoid. The median absolute error was 0.126 Gy for HRCTV, 0.041 Gy for the bladder, 0.0013 Gy for rectum, and 0.019 Gy for sigmoid. Our results showed that the predicted mean D2cc OAR doses in the bladder, rectum, sigmoid were 3.51±1.25, 3.11±1.23 and 4.02±2.23 Gy in comparison to 4.21±1.23, 4.20±1.02, 4.80±1.59 Gy in clinical plans respectively. The predicted D90 of the HRCTV was 6.72±0.99 Gy in comparison with 6.83±1.72 Gy in clinical plans. The predicted maximum dose to bladder, sigmoid, and rectum were 7.51±1.10, 3.81±1.27, 3.61±1.16 Gy in comparison to 7.33±1.03, 4.66±2.06, 4.33±1.75 Gy in clinical plans, respectively, indicating a good potential to predict useful dosimetric indices and facilitate an improvement in brachytherapy treatment workflow. The proposed model needs less than 5 seconds to predict a full 3D dose distribution of 64 × 64 × 64 voxels for any new patient plan, thus making it sufficient for near real-time applications and aid in decision-making in clinic. Conclusions The 3D U-Net model we have implemented demonstrates competitive capability in predicting accurate dose distributions and DVH indices with consistent quality. The proposed model can be used to predict 3D dose distributions for near real-","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"135 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":"135434533","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}
Pub Date : 2023-09-01DOI: 10.1016/j.brachy.2023.06.198
Abigail Dare, Zachary Horne
Purpose To compare dosimetric values for interstitial HDR brachytherapy cases using both manual and inverse planning techniques and refine optimization results for clinical use. Materials and Methods Ten plans for prior interstitial brachytherapy were selected for analysis representing a variety of treatments: Elekta's Venezia applicator with needles (4), Best Medical's Syed/Neblett gynecological template (3), and Best Medical's prostate template (3). Each plan, previously manually optimized (MO), was optimized in Oncentra (Elekta) using both IPSA and HIPO inverse planning algorithms. For the first plan of each type, optimization parameters were iteratively adjusted from comparison to the MO treated plan. The parameters were then saved as a template to apply to future plans of the same type. Dosimetric quantities were recorded for each optimization type for comparison. For the optimized cases, the metrics collected were clinically relevant values representing target coverage and OAR constraints. Results For target coverage (HRCTV D90%), IPSA produced lower coverage on average for Venezia (-15.5%) and Syed (-0.2%) cases when compared to the MO plan and higher for prostate (4.3%). HIPO resulted in higher coverage for Venezia (1.3%) and prostate (1.5%) and lower for Syed (-0.7%). OAR doses were assessed normalized to HRCTV D90% equal to prescription dose. IPSA had lower OAR metrics on average for Syed (-8.3%) and prostate (-3.2%) and higher for Venezia (0.1%). HIPO gave lower OAR metrics for Venezia (-1.9%) and Syed (-4.2%) and higher for prostate (2.2%). Conclusions Overall, HIPO was more consistent in comparable or improved results to the clinically treated MO plan. Treatment planning time for clinical interstitial cases has reduced, and we have adopted a hybrid optimization approach starting with HIPO inverse optimization and then performing manual changes as needed. Future work includes refining optimization parameters to be globally applicable for each treatment type and warrant less manual optimization. To compare dosimetric values for interstitial HDR brachytherapy cases using both manual and inverse planning techniques and refine optimization results for clinical use. Ten plans for prior interstitial brachytherapy were selected for analysis representing a variety of treatments: Elekta's Venezia applicator with needles (4), Best Medical's Syed/Neblett gynecological template (3), and Best Medical's prostate template (3). Each plan, previously manually optimized (MO), was optimized in Oncentra (Elekta) using both IPSA and HIPO inverse planning algorithms. For the first plan of each type, optimization parameters were iteratively adjusted from comparison to the MO treated plan. The parameters were then saved as a template to apply to future plans of the same type. Dosimetric quantities were recorded for each optimization type for comparison. For the optimized cases, the metrics collected were clinically relevant values representing target coverag
{"title":"PO97","authors":"Abigail Dare, Zachary Horne","doi":"10.1016/j.brachy.2023.06.198","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.198","url":null,"abstract":"Purpose To compare dosimetric values for interstitial HDR brachytherapy cases using both manual and inverse planning techniques and refine optimization results for clinical use. Materials and Methods Ten plans for prior interstitial brachytherapy were selected for analysis representing a variety of treatments: Elekta's Venezia applicator with needles (4), Best Medical's Syed/Neblett gynecological template (3), and Best Medical's prostate template (3). Each plan, previously manually optimized (MO), was optimized in Oncentra (Elekta) using both IPSA and HIPO inverse planning algorithms. For the first plan of each type, optimization parameters were iteratively adjusted from comparison to the MO treated plan. The parameters were then saved as a template to apply to future plans of the same type. Dosimetric quantities were recorded for each optimization type for comparison. For the optimized cases, the metrics collected were clinically relevant values representing target coverage and OAR constraints. Results For target coverage (HRCTV D90%), IPSA produced lower coverage on average for Venezia (-15.5%) and Syed (-0.2%) cases when compared to the MO plan and higher for prostate (4.3%). HIPO resulted in higher coverage for Venezia (1.3%) and prostate (1.5%) and lower for Syed (-0.7%). OAR doses were assessed normalized to HRCTV D90% equal to prescription dose. IPSA had lower OAR metrics on average for Syed (-8.3%) and prostate (-3.2%) and higher for Venezia (0.1%). HIPO gave lower OAR metrics for Venezia (-1.9%) and Syed (-4.2%) and higher for prostate (2.2%). Conclusions Overall, HIPO was more consistent in comparable or improved results to the clinically treated MO plan. Treatment planning time for clinical interstitial cases has reduced, and we have adopted a hybrid optimization approach starting with HIPO inverse optimization and then performing manual changes as needed. Future work includes refining optimization parameters to be globally applicable for each treatment type and warrant less manual optimization. To compare dosimetric values for interstitial HDR brachytherapy cases using both manual and inverse planning techniques and refine optimization results for clinical use. Ten plans for prior interstitial brachytherapy were selected for analysis representing a variety of treatments: Elekta's Venezia applicator with needles (4), Best Medical's Syed/Neblett gynecological template (3), and Best Medical's prostate template (3). Each plan, previously manually optimized (MO), was optimized in Oncentra (Elekta) using both IPSA and HIPO inverse planning algorithms. For the first plan of each type, optimization parameters were iteratively adjusted from comparison to the MO treated plan. The parameters were then saved as a template to apply to future plans of the same type. Dosimetric quantities were recorded for each optimization type for comparison. For the optimized cases, the metrics collected were clinically relevant values representing target coverag","PeriodicalId":93914,"journal":{"name":"Brachytherapy","volume":"46 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":"135434534","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}
Pub Date : 2023-09-01DOI: 10.1016/j.brachy.2023.06.207
Irina Vasilievna Horot
Ways of the treatment of non-melanomas skin cancer are still under discussion. Recurrences after different modalities usage are still high. It applies to surgery, external irradiation and brachytherapy. Using brachytherapy, we can achieve very high local doses. Moreover, they can be higher, the lower the volume of irradiation. In this sense, brachytherapy has its own characteristics that greatly distinguish it from other approaches, but there are still many unresolved questions in brachytherapy itself. For example, irradiating the tumor with an application method or with injection applicators into the tumor, how to normalize the dose, adhering to the prescribed restrictions. Purpose The aim of the work was to compare the results of three brachytherapy methods in non melanoma skin cancer. Patients and Methods We work at Microselectron, 30 channels. Planning of the isodose distribution is based on CT scans. 370 patients have been treated since 2012. Essential is the question of how many applicators to use and how to distribute them spatially. We use all available methods - iron needles and flexible applicators for interstitial brachytherapy, as well as application methods with individual masks and individual applicator placement. We use boluses to equalize the dose and the arrangement of applicators in several rows. A change in the location of the applicators changes something in the dose distribution that can be used to improve the distribution. That is, for example, to increase the dose value at the center of the tumor and increase the dose-fall gradient at the edges. When we use the applicator method with an individual mask our doses amounted to 36 Gy, 6 Gy, 6 fractions 5 times per week. The normalization of the dose depends on the tumor size, location and some other parameters. In the case of rigid needles insertion we prescribe 8 Gy twice per week, 4 fractions, total dose is equal to 32 Gy. In the case of intratissue irradiation with flexible applicators the total dose is equal to 42.5 Gy, 5.2 Gy, 8 fractions 5 times per week. Interstitial method is used as a rule in the case of volumetric tumors. Results Using iron needles has several advantages - extraction of needles takes place immediately after the delivery of dose in every fraction. The swelling disappears during one hour after extraction, and wound healing after irradiation happens faster. It is especially significant in treating eyelids. However, all three methods are comparable in results when the dose is properly normalized. Conclusion We came to the conclusion that the choice of the method of irradiation, as well as the normalization of the dose in brachytherapy for non-melanoma skin cancer, depends mainly on the characteristics of the tumor and its location. Ways of the treatment of non-melanomas skin cancer are still under discussion. Recurrences after different modalities usage are still high. It applies to surgery, external irradiation and brachytherapy. Using brachytherapy, we
{"title":"PO106","authors":"Irina Vasilievna Horot","doi":"10.1016/j.brachy.2023.06.207","DOIUrl":"https://doi.org/10.1016/j.brachy.2023.06.207","url":null,"abstract":"Ways of the treatment of non-melanomas skin cancer are still under discussion. Recurrences after different modalities usage are still high. It applies to surgery, external irradiation and brachytherapy. Using brachytherapy, we can achieve very high local doses. Moreover, they can be higher, the lower the volume of irradiation. In this sense, brachytherapy has its own characteristics that greatly distinguish it from other approaches, but there are still many unresolved questions in brachytherapy itself. For example, irradiating the tumor with an application method or with injection applicators into the tumor, how to normalize the dose, adhering to the prescribed restrictions. Purpose The aim of the work was to compare the results of three brachytherapy methods in non melanoma skin cancer. Patients and Methods We work at Microselectron, 30 channels. Planning of the isodose distribution is based on CT scans. 370 patients have been treated since 2012. Essential is the question of how many applicators to use and how to distribute them spatially. We use all available methods - iron needles and flexible applicators for interstitial brachytherapy, as well as application methods with individual masks and individual applicator placement. We use boluses to equalize the dose and the arrangement of applicators in several rows. A change in the location of the applicators changes something in the dose distribution that can be used to improve the distribution. That is, for example, to increase the dose value at the center of the tumor and increase the dose-fall gradient at the edges. When we use the applicator method with an individual mask our doses amounted to 36 Gy, 6 Gy, 6 fractions 5 times per week. The normalization of the dose depends on the tumor size, location and some other parameters. In the case of rigid needles insertion we prescribe 8 Gy twice per week, 4 fractions, total dose is equal to 32 Gy. In the case of intratissue irradiation with flexible applicators the total dose is equal to 42.5 Gy, 5.2 Gy, 8 fractions 5 times per week. Interstitial method is used as a rule in the case of volumetric tumors. Results Using iron needles has several advantages - extraction of needles takes place immediately after the delivery of dose in every fraction. The swelling disappears during one hour after extraction, and wound healing after irradiation happens faster. It is especially significant in treating eyelids. However, all three methods are comparable in results when the dose is properly normalized. Conclusion We came to the conclusion that the choice of the method of irradiation, as well as the normalization of the dose in brachytherapy for non-melanoma skin cancer, depends mainly on the characteristics of the tumor and its location. Ways of the treatment of non-melanomas skin cancer are still under discussion. Recurrences after different modalities usage are still high. It applies to surgery, external irradiation and brachytherapy. Using brachytherapy, we ","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":"135434209","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}
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