Medical Dosimetry最新文献

{"title":"An assessment of the influence of trade-off optimization in commercial knowledge based planning library creation for tongue cancer patients.","authors":"Subhra S Biswal, Biplab Sarkar, Monika Goyal, Tharmarnadar Ganesh, Tanweer Shahid, Jibak Bhattacharya","doi":"10.1016/j.meddos.2024.10.006","DOIUrl":"https://doi.org/10.1016/j.meddos.2024.10.006","url":null,"abstract":"<p><p>This article aims to compare the dosimetric performance between knowledge-based plan (KBP) libraries with and without trade-off (TO) exploration using multicriterial optimization (MCO) for tongue cancer patients. The trade-off optimized library (KBP_MCO) contains a minimal number of constituent plans, whereas two nontrade-off optimized libraries contain a minimal and a large number of treatment plans, respectively. Three KBP libraries were created: KBP_100 and KBP_20, each comprising of 100 and 20 manually optimized plans, respectively. Additionally, another KBP library (KBP_MCO_20) was created by reoptimizing the constituent plans from KBP_20 using MCO techniques. A total of 70 tongue plans were validated through these libraries. Validation plans were evaluated for PTV and organ at risk (OAR) doses. Greenhouse-Geisser analysis (ANOVA) and the Bonferroni procedure (t-test) were used for statistical evaluation. The mean PTVD95% for KBP_100, KBP_20, and KBP_MCO_20 was 98.4% ± 0.3%, 98.9% ± 0.2%, and 98.7% ± 0.2%, respectively. The statistical significance of PTVD95% for the 3 possible combinations-KBP_100 vs KBP_20, KBP_100 vs KBP_MCO_20, and KBP_20 vs KBP_MCO_20 were statistically significant with p < 0.001. Spinal cord doses for KBP_100, KBP_20, and KBP_MCO_20 were 29.6 ± 1.8 Gy, 31.2 ± 2.5 Gy, and 26.8 ± 1.9 Gy, respectively, with p(KBP_100 vs KBP_20) = 0.14, p(KBP_100 vs KBP_MCO_20) = 0.001, and p(KBP_20 vs KBP_MCO_20) < 0.001. Only the first comparison showed a statistically insignificant variation. A trade-off optimized plan library with a minimal number of patients (20) yields better performance for serial structures (spinal cord and brainstem) compared to large manually optimized KBP libraries. For other organs at risk (OARs) and target dose coverage, although statistical differences were significant in most instances, the differences in physical dose were small and probably will not yield any significant clinical differences.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142792473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel application of an adapted virtual cone technique for the radiosurgical treatment of a 3 mm brain metastasis with a standard multileaf collimator.","authors":"Eric Lobb","doi":"10.1016/j.meddos.2024.10.005","DOIUrl":"https://doi.org/10.1016/j.meddos.2024.10.005","url":null,"abstract":"<p><p>The virtual cone is an innovative MLC-based technique for generating dose distributions comparable to those of physical stereotactic cones. Initially designed for functional radiosurgery applications using a high-definition multileaf collimator (MLC) with 2.5 mm leaf width, this technique has been adapted to a standard 5 mm MLC system for treating small brain metastases. The adapted technique uses preconfigured location-specific control point sequences to produce spherical dose distributions with sharp dose gradients, and facilitates efficient planning through parallelizable template-based workflows. This report highlights the use of the adapted virtual cone technique for treating a 57-year-old patient with a 3 mm brain metastasis from metastatic papillary thyroid carcinoma using a standard multileaf collimator.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142741167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dosimetric comparison between laterality-specific and general knowledge-based planning models for nonsmall cell lung cancer.","authors":"Julia Seng, Kirk Luca, Justin Roper, Aparna H Kesarwala, Shadab Momin","doi":"10.1016/j.meddos.2024.10.003","DOIUrl":"https://doi.org/10.1016/j.meddos.2024.10.003","url":null,"abstract":"<p><p>To investigate the dosimetric impact of laterality-specific RapidPlan models for nonsmall cell lung cancer. Three RapidPlan models were developed and validated for Right, Left, and General conventional lung radiotherapy. Each model was trained using 50 plans. The right and left models consisted of plans corresponding to their respective laterality. Twenty-five cases were randomly chosen from each laterality-specific model to craft a general model. All models shared identical optimization objectives and the same target and OAR structures. Validation included 13 right-sided and 13 left-sided cases optimized using each RapidPlan model without intervention and normalized such that the prescription dose covered 95% of the target volume. Statistical analysis using a paired sample t-test (p < 0.01) assessed dosimetric endpoints based on RTOG 0617 criteria. For right-sided cases, spinal cord Dmax and D0.03cc were lowest in the left model and highest in the right model (21.08 Gy and 21.22 Gy vs 23.67 Gy and 24.08 Gy). D_max and D_0.03cc esophagus mean dose was also lower in the left model compared to the right model (p < 0.01) for both left and right-sided cases. However, overall plan quality exhibited no substantial difference between general and laterality-specific models. Despite observing small but statistically significant differences, there is no discernible difference in plan quality between laterality-specific and general models, suggesting that a single RapidPlan model is sufficient.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142734357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dosimetric effects of the leaf positioning error of the halcyon(2.0) dual-layer multileaf collimator (MLC) on the rectal cancer radiotherapy.","authors":"Jiajun Zheng, Yatian Liu, Jianfeng Wu, Li Sun, Dan Zong, Xia He","doi":"10.1016/j.meddos.2024.10.004","DOIUrl":"https://doi.org/10.1016/j.meddos.2024.10.004","url":null,"abstract":"<p><p>To study dosimetric effects of leaf positioning errors (LPEs) of the Halcyon(2.0) dual-layer MLC on the long-course chemoradiotherapy (LCCRT) with 45∼50.4 Gy in 25∼28 fractions for rectal cancer. Nine Halcyon(2.0)-based LCCRT plans of rectal cancer were retrospectively involved. Four types of LPEs were introduced: (1) Uniformly distributed dual-layer random LPEs (Dual-R); (2) Proximal-layer systemic LPEs (P-S); (3) Distal-layer systemic LPEs (D-S); (4) Dual-layer systemic LPEs (Dual-S). The sensitivities of D_98%, D_2% and the Equivalent Uniform Dose (EUD) of PTV to various LPEs were investigated as well as varying ranges of EUDs of OARs. The sensitivities of D_98% and EUD of PTV to Dual-R was -0.65%/mm and -0.38%/mm; the sensitivities of both indices to the P-S and D-S were similar to each other, ranging from 1.92%/mm to 2.87%/mm; both indices were more sensitive to the Dual-S and values were 4.97%/mm and 3.84%/mm respectively. The EUD changes of the bladder, and left and right femoral heads were from -13.23% to 14.82%. Single-side systemic LPEs lower than 0.7 mm are acceptable for Halcyon(2.0)-based LCCRT, while dual-layer systemic LPEs lower than 0.4 mm are acceptable, considering relative changes of 2% for D_98% of PTV as threshold.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142640084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of dose and anatomy variability for nasopharyngeal carcinoma radiotherapy with a new fully integrated CT-linac.","authors":"Fan Zhang, Jing Liu, Mi Zhou, Xutong Li, Lu Yue, Chong Zhao, Zhenyu Qi, Xiaowu Deng, Yinglin Peng, Zhiping Luo","doi":"10.1016/j.meddos.2024.09.005","DOIUrl":"https://doi.org/10.1016/j.meddos.2024.09.005","url":null,"abstract":"<p><p>The goal of this study was to investigate the variability of target volume and parotid gland dose distribution for nasopharyngeal carcinoma (NPC), and to explore the shifting patterns of parotid gland centroid and neck radius during radiotherapy. Twenty patients with NPC were enrolled. The target volume dose difference between planning dose and recalculated dose on weekly CT was analyzed. The recalculated doses on every weekly CT were cumulated to assess the difference between delivered dose and planning dose. The relationship of parotid gland centroid deviation with dose was studied, and the shrinking distances of neck radius were calculated for cervical vertebra 1, 2, 3 levels (C1, C2, C3). The ratio of GTVs and CTVs doses on weekly CTs to the doses on planning CT was all above 0.98; the dose of PTVs on weekly CT tended to decrease compared with planning. RMD was defined as the ratio of the mean dose of the left and right parotid glands (L-PG, R-PG) to the planning mean dose. The fitted relationships of RMD and the deviation of centroid (D) for L-PG and R-PG were: RMD=0.37*D+0.98 (R² = 0.62, p < 0.001) and RMD = 0.33*D+0.97 (R² = 0.72, p < 0.001), respectively. The order of neck radius shrinking distance at different levels was C1>C2=C3. In this study, we quantitatively analyzed the dosimetric variabilities of target volumes, and established linear models of parotid gland dose and its centroid deviation, which provides fractional and full-course dose evaluation during radiotherapy for NPC.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142584780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Members List & Corporate Members List, Winter 2024","authors":"","doi":"10.1016/j.meddos.2024.10.002","DOIUrl":"10.1016/j.meddos.2024.10.002","url":null,"abstract":"","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"49 4","pages":"Page 399"},"PeriodicalIF":1.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142551906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Directed Journal Reading (DJR) Program, Winter 2024","authors":"","doi":"10.1016/j.meddos.2024.10.001","DOIUrl":"10.1016/j.meddos.2024.10.001","url":null,"abstract":"","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"49 4","pages":"Page 398"},"PeriodicalIF":1.1,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142551905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of minimum monitor unit per dynamic control point on intensity‐modulated radiotherapy planning for nasopharyngeal carcinoma: A retrospective study","authors":"Xiwei Chen ,&nbsp;Yuan Cheng ,&nbsp;Weiwei Wu ,&nbsp;Yadi He ,&nbsp;Yangming Zhang ,&nbsp;Liwan Han ,&nbsp;Gaokui He ,&nbsp;Zhenghuan Li","doi":"10.1016/j.meddos.2024.09.003","DOIUrl":"10.1016/j.meddos.2024.09.003","url":null,"abstract":"<div><div>The present study aimed to improve the dose distribution of radiotherapy planning for nasopharyngeal carcinoma (NPC) by comparing the effects of various minimum monitor units (MUs) per dynamic control point (MMCP) values on the quality and execution efficiency of dynamic intensity-modulated radiotherapy (IMRT) planning. Thirty-four clinically implemented dynamic IMRT plans for patients with NPC were retrospectively selected. In total, 170 plans were obtained by modifying only the MMCP values (set as 1, 3, 5, 7, and 9) in the treatment planning system's (TPS) optimization parameters. These plans were divided into 5 groups. Analyzing the effects of MMCP on the target and organ dose at risk (OAR), also the execution efficiency of the treatment plan in each group and using a quality score system, we conducted an objective quantitative study of the dose distribution and execution efficiency. The target dose evaluation indicators (target coverage (TC), homogeneity index (HI), and conformity index (CI)) of all IMRT plans showed a trend of variation with an increase in MMCP values, and the difference was statistically significant when MMCP values were 5, 7, 9, and 1 (<em>p</em> &lt; 0.05). With an increase in MMCP, the dose to OAR slightly increased, but the difference was not statistically significant (<em>p</em> &gt; 0.05). With an increase in MMCP, the average number of MUs per segment significantly increased (<em>p</em> &lt; 0.01). The groups based on MMCP values of 1, 3, 5, 7, and 9 received quality score system of 1.188, 1.180, 1.171, 0.987, and 1.184, respectively, with the MMCP7 group achieving the lowest score, indicating that this plan had the highest overall quality. The MMCP value for dynamic IMRT planning in the Monaco TPS for patients with NPC should be set to 7 to achieve fewer segments, the best execution efficiency without significantly deteriorating the target and OAR dose.</div></div>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"50 1","pages":"Pages 96-101"},"PeriodicalIF":1.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142479169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling of silicone breast implants for radiotherapy treatment planning.","authors":"Joshua Kirby, Nick West","doi":"10.1016/j.meddos.2024.09.004","DOIUrl":"https://doi.org/10.1016/j.meddos.2024.09.004","url":null,"abstract":"<p><p>There has been no published work characterizing the attenuation of silicone breast implants in MV energy photon beams. As a result of systematic out of tolerance in-vivo dosimetry results, this report investigates whether the CT Hounsfield Units to electron density curve provides an accurate estimate of attenuation in silicone implants. A CT scan of a silicone breast implant centered on top of WT1 blocks was acquired with simple 6 MV and 10 MV plans created. Dose was calculated using the CT and a collapsed cone algorithm. The predicted dose was compared to doses measured with ionization chamber at 2 points downstream of the implant. Predicted dose from the treatment planning system was 0.9-1.7% lower than measured. The use of a density override on the implant of water (1 g/cm³) improved agreement to less than 1% for all energies and measurement depths. We conclude that the use of CT Hounsfield Units for silicone breast implants leads to an under-estimation of dose in MV photon fields. Dose accuracy has been shown to be improved in the treatment planning system when silicone breast implants have a density override of water.</p>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142479170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated tumor localization and segmentation through hybrid neural network in head and neck cancer","authors":"Ahmad Qasem MSc. ,&nbsp;Zhiguo Zhou Ph.D.","doi":"10.1016/j.meddos.2024.09.001","DOIUrl":"10.1016/j.meddos.2024.09.001","url":null,"abstract":"<div><h3>Purpose</h3><div>Head and Neck (H&amp;N) cancer accounts for 3% of cancer cases in the United States. Precise tumor segmentation in H&amp;N is of utmost importance for treatment planning and administering personalized treatment dose. We aimed to develop an automatic tumor localization and segmentation method in enhancing the clinical efficiency and ultimately improving treatment outcomes.</div></div><div><h3>Approach</h3><div>In this study, a hybrid neural network (HNN) was developed by integrating object localization and segmentation into a unified framework. It consists of 4 stages: preprocessing, HNN training, object localization and segmentation, and postprocessing. We utilized a dataset consisting of PET and CT images for 48 patients and designed a Hybrid Neural Network (HNN) which consists of YOLOv4 object detection model + U-Net model for image segmentation. YOLOv4 was used to identify regions of interests (ROI), while the U-Net was employed for the precise image segmentation. In our experiments we considered 2 object detection architectures to identify possible tumor regions, namely YOLOv4 and Faster-RCNN. The evaluation metrics for both were evaluated and compared.</div></div><div><h3>Results</h3><div>We evaluated the performance of 3 model combinations: YOLOv4 + U-Net, Faster-RCNN + U-Net, and U-Net alone. The models were evaluated based on Sensitivity, Specificity, F-Score, and Intersection over Union (IoU). YOLOv4 + U-Net achieved the best values with Sensitivity of 0.89, Specificity of 0.99, F-Score of 0.84, and IoU of 0.72.</div></div><div><h3>Conclusion</h3><div>A new hybrid neural network (HNN) for fully automatic tumor localization and segmentation was developed and the experimental results. showcased the HNN's impressive performance, indicating its potential to be a valuable H&amp;N tumor segmentation tool.</div></div>","PeriodicalId":49837,"journal":{"name":"Medical Dosimetry","volume":"50 1","pages":"Pages 80-90"},"PeriodicalIF":1.1,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142401782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}