International Journal of Medical Physics, Clinical Engineering and Radiation Oncology最新文献_第3页

Distance to Isocenter Directly Affects Margin and Inappropriate Margin Increases the Risk of Local Control Failure in LINAC-Based Single-Isocenter SRS or SRT for Multiple Brain Metastases 在基于linac的单等中心SRS或SRT治疗多发性脑转移时，与等中心的距离直接影响切缘，切缘不合适增加局部控制失败的风险

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology Pub Date : 2022-01-01 DOI: 10.4236/ijmpcero.2022.112010

Jun-fang Gao

引用次数: 0

Use of High Definition Multileaf Colimator for the Treatment of Trigeminal Neuralgia 应用高清晰度多叶准直仪治疗三叉神经痛

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology Pub Date : 2022-01-01 DOI: 10.4236/ijmpcero.2022.113013

Eduardo Cabello Murillo, Ana Milanés Gaillet, Gustavo Pozo Rodriguez, Ángel Gaitán Simón, P. Hernández, Marta Rodríguez, A. F. Sanchez, R. D. Fuentes

引用次数: 0

Empirical Formalism for the Phantom Scatter Factor of Small Fields: Using Different Density Media 小场幻像散射系数的经验形式:使用不同密度介质

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology Pub Date : 2022-01-01 DOI: 10.4236/ijmpcero.2022.111004

Saed J. Al Atawneh

引用次数: 0

Extracting 3D Angiography Data from Simulated Computed Tomography Angiography Scans Using Low Iodine Contrast Agent 利用低碘造影剂从模拟计算机断层血管造影扫描中提取3D血管造影数据

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology Pub Date : 2022-01-01 DOI: 10.4236/ijmpcero.2022.113012

A. Alyassin

{"title":"Extracting 3D Angiography Data from Simulated Computed Tomography Angiography Scans Using Low Iodine Contrast Agent","authors":"A. Alyassin","doi":"10.4236/ijmpcero.2022.113012","DOIUrl":"https://doi.org/10.4236/ijmpcero.2022.113012","url":null,"abstract":"The purpose of this research is to investigate the feasibility of using low contrast agent concentration with X-ray computed tomography in visualizing and diagnosing the human vascular system while minimizing the risk of tox-icity to the patient. This research investigated the effect of several iodine contrast agent concentrations on the ability to extract and visualize human vessels using simulated computed tomography scans. Monte Carlo simulation was used to perform these computed tomography acquisitions. The simulated patient was based on actual computed tomography angiography data, where a technique was developed to simulate brain vessels with contrast agents rang-ing from 0 mg to 20 mg of iodine. The simulation used segmented patient data along with basic image processing techniques to model the various levels of iodine concentrations. Cone beam computed tomography projections of a patient injected with and without iodine were acquired in the simulations. Subtraction of the corresponding projections was performed to generate images caused by the contrast agent. Then, histogram analysis of these differ-ences was used to assess the validity of extracting and visualizing the human vessels. The smallest amount of iodine, 0.5 mg, helped better visualize the brain vessels and 2 mg of iodine was high enough to show almost 90% of the vessels. Additionally, the vessels were clearly visible in all the subtracted images. This research showed very promising outcomes in using low concentrations of iodine. Thus, this study proposes for the pharmaceutical companies and others interested to clinically investigate and evaluate the efficacy of using low concentrations of iodine and the associated side effects.","PeriodicalId":14028,"journal":{"name":"International Journal of Medical Physics, Clinical Engineering and Radiation Oncology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73801103","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}

引用次数: 0

Dosimetric Effects of Thermoplastic Immobilizing Devices on Surface Dose 热塑性固定装置对表面剂量的剂量学效应

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology Pub Date : 2022-01-01 DOI: 10.4236/ijmpcero.2022.111002

O. Adu-Poku, E. Addison, C. Schandorf, F. Hasford, S. Inkoom, J. Adom, Akosah Kingsley, Eunice Arthur, L. Owusu-Agyapong

引用次数: 1

Risk Management of Clinical Reference Dosimetry of a Large Hospital Network Using Statistical Process Control. 基于统计过程控制的大型医院网络临床参考剂量学风险管理

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology Pub Date : 2021-08-01 Epub Date: 2021-07-30 DOI: 10.4236/ijmpcero.2021.103011

Seng-Boh Lim, Thomas LoSasso, Maria Chan, Laura Cervino, Dale Michael Lovelock

{"title":"Risk Management of Clinical Reference Dosimetry of a Large Hospital Network Using Statistical Process Control.","authors":"Seng-Boh Lim, Thomas LoSasso, Maria Chan, Laura Cervino, Dale Michael Lovelock","doi":"10.4236/ijmpcero.2021.103011","DOIUrl":"https://doi.org/10.4236/ijmpcero.2021.103011","url":null,"abstract":"Managing TG-51 reference dosimetry in a large hospital network can be a challenging task. The objectives of this study are to investigate the effectiveness of using Statistical Process Control (SPC) to manage TG-51 workflow in such a network. All the sites in the network performed the annual reference dosimetry in water according to TG-51. These data were used to cross-calibrate the same ion chambers in plastic phantoms for monthly QA output measurements. An energy-specific dimensionless beam quality cross-calibration factor, <math> <mrow><msubsup><mi>k</mi> <mrow><mi>q</mi> <mi>n</mi></mrow> <mrow><mi>S</mi> <mi>W</mi></mrow> </msubsup> </mrow> </math> , was derived to monitor the process across multiple sites. The SPC analysis was then performed to obtain the mean, <math> <mrow><mrow><mo>〈</mo> <mrow><msubsup><mi>k</mi> <mrow><mi>q</mi> <mi>n</mi></mrow> <mrow><mi>S</mi> <mi>W</mi></mrow> </msubsup> </mrow> <mo>〉</mo></mrow> </mrow> </math> , standard deviation, σ k , the Upper Control Limit (UCL) and Lower Control Limit (LCL) in each beam. This process was first applied to 15 years of historical data at the main campus to assess the effectiveness of the process. A two-year prospective study including all 30 linear accelerators spread over the main campus and seven satellites in the network followed. The ranges of the control limits (±3σ) were found to be in the range of 1.7% - 2.6% and 3.3% - 4.2% for the main campus and the satellite sites respectively. The wider range in the satellite sites was attributed to variations in the workflow. Standardization of workflow was also found to be effective in narrowing the control limits. The SPC is effective in identifying variations in the workflow and was shown to be an effective tool in managing large network reference dosimetry.","PeriodicalId":14028,"journal":{"name":"International Journal of Medical Physics, Clinical Engineering and Radiation Oncology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8360384/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39313273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Constraint Analysis and Bladder Wall Low-Dose-Constraint Reduction in Five-Fraction Urethra-Sparing Prostate SBRT 五段式保尿道前列腺SBRT的约束分析和膀胱壁低剂量约束降低

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology Pub Date : 2021-07-29 DOI: 10.4236/ijmpcero.2021.103012

A. Prado, Inés Flores, Á. Montero, M. A. de la Casa, L. Alonso, Jaime Martí, P. Fernández-Letón, C. Rubio

{"title":"Constraint Analysis and Bladder Wall Low-Dose-Constraint Reduction in Five-Fraction Urethra-Sparing Prostate SBRT","authors":"A. Prado, Inés Flores, Á. Montero, M. A. de la Casa, L. Alonso, Jaime Martí, P. Fernández-Letón, C. Rubio","doi":"10.4236/ijmpcero.2021.103012","DOIUrl":"https://doi.org/10.4236/ijmpcero.2021.103012","url":null,"abstract":"Aim: To compare and analyze dose constraints and target coverage results and to reduce Bladder Wall (Bwall) V18.12 for prostate Stereotactic-Body Radiation Therapy (SBRT) when Seminal Vesicles (SSVV) are included or not. Several indicators based on intersection volumes are obtained to predict constraint fulfillment. Background: Due to prostate’s low alpha-beta ratio and the possibility of increasing the therapeutic ratio several moderate and extreme hypofractionation schemes have been proposed. The scheme selected was a fivefraction urethra-sparing prostate SBRT. Materials and Methods: 150 patients divided into two groups according to the inclusion of SSVV in PTV or not were analyzed. Histograms, average values, standard deviations and degrees of fulfillment were obtained for each constraint or goal and group. A possible reduction of the Bwall V18.12 was addressed by re-optimizing fifty randomly chosen patients. Predictors of constraint fulfilling were obtained by using the intersections of Bwall and Rectum Wall (Rwall) with the PTV. Results: Significant differences in Rwall V32.62 and V29 were obtained when evaluating the influence of SSVV inclusion. A reduction of 12% in the Bwall V18.12 constraint was achieved without compromising coverage and OARs doses. No dependence on the inclusion of SSVV was found. Conclusions: Statistically significant differences have been found in Rwall intermediate-dose constraint when SSVV was included. A reduction of 12% in the Bwall V18.12 constraint has been achieved without compromising the PTV coverage and the rest of OARs constraints. Constraint fulfillment predictors could be useful to evaluate the feasibility of prostate SBRT prior to the planning process for every single patient.","PeriodicalId":14028,"journal":{"name":"International Journal of Medical Physics, Clinical Engineering and Radiation Oncology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88522554","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}

引用次数: 0

Dosimetric Comparison: Volumetric Modulated Arc Therapy (VMAT) and 3D Conformal Radiotherapy (3D-CRT) in High Grade Glioma Cancer—Experience of Casablanca Cancer Center at the Cheikh Khalifa International University Hospital 剂量学比较:体积调制电弧治疗(VMAT)和三维适形放疗(3D- crt)治疗高级别胶质瘤-谢赫哈利法国际大学医院卡萨布兰卡癌症中心的经验

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology Pub Date : 2021-05-18 DOI: 10.4236/IJMPCERO.2021.102010

Imane Benali, Othmane Kaanouch, A. Naim, Hanae El Gouach, Z. Dahbi, F. Kouhen

{"title":"Dosimetric Comparison: Volumetric Modulated Arc Therapy (VMAT) and 3D Conformal Radiotherapy (3D-CRT) in High Grade Glioma Cancer—Experience of Casablanca Cancer Center at the Cheikh Khalifa International University Hospital","authors":"Imane Benali, Othmane Kaanouch, A. Naim, Hanae El Gouach, Z. Dahbi, F. Kouhen","doi":"10.4236/IJMPCERO.2021.102010","DOIUrl":"https://doi.org/10.4236/IJMPCERO.2021.102010","url":null,"abstract":"Background: Intensity Modulated Radiation Therapy (IMRT) is currently employed as a \u0000major arm of treatment in multiforme glioblastoma (GBM). The present study \u0000aimed to compare 3D-CRT with IMRT to assess tumor volume coverage and OAR \u0000sparing for the treatment of malignant \u0000gliomas. Materials and methods: We assessed 22 anonymized \u0000patients datasets with High Grade Glioblastoma who had undergone post-operative Intensity \u0000Modulated Radiotherapy (IMRT) and 3D Conformal Radiotherapy (3D-CRT), This \u0000study will compare and contrast treatment plans Rapidarc and 3D-CRT to \u0000determine which technology improves \u0000significantly dosimetric parameters. Results: Plans will be assessed by \u0000reviewing the coverage of the PTV using mean, maximum and minimum doses while \u0000the OAR doses will be compared using the maximal doses for each, as set out in \u0000the QUANTEC dose limits. Conclusion: The use of IMRT seems a superior \u0000technique as compared to 3D-CRT for the treatment of malignant gliomas having \u0000the potential to increase the dose to the PTV while sparing OARs optimally.","PeriodicalId":14028,"journal":{"name":"International Journal of Medical Physics, Clinical Engineering and Radiation Oncology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78939148","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}

引用次数: 1

Dosimetric Effects Due to Inter-Observer Variability of Organ Contouring When Utilizing a Knowledge-Based Planning System for Prostate Cancer 当使用基于知识的前列腺癌计划系统时，由于器官轮廓的观察者间变异性的剂量学效应

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology Pub Date : 2021-05-18 DOI: 10.4236/IJMPCERO.2021.102005

Han Liu, Christopher Amaloo, B. Sintay, D. Wiant

{"title":"Dosimetric Effects Due to Inter-Observer Variability of Organ Contouring When Utilizing a Knowledge-Based Planning System for Prostate Cancer","authors":"Han Liu, Christopher Amaloo, B. Sintay, D. Wiant","doi":"10.4236/IJMPCERO.2021.102005","DOIUrl":"https://doi.org/10.4236/IJMPCERO.2021.102005","url":null,"abstract":"Purpose: Radiotherapy is a widely accepted standard of care for early-stage prostate \u0000cancer, and it is believed that the plan quality and treatment outcome are \u0000associated with contour accuracy of both the target and organs-at-risk (OAR). \u0000The purposes of this study are to 1) assess geometric and dosimetric \u0000uncertainties due to inter-observer contour variabilities and 2) evaluate the \u0000effectiveness of geometric indicators to predict target dosimetry in prostate \u0000radiotherapy. Methods: Twenty prostate patients were selected for this \u0000retrospective study. Five experienced clinicians created unique structure sets \u0000containing prostate, seminal vesicles, bladder, and rectum for each patient. A \u0000fully automated script and knowledge-based planning routine were utilized to \u0000create standardized and unbiased plans that could be used to evaluate changes \u0000in isodose distributions due to inter-observer variability in structure \u0000segmentation. Plans were created on a “gold-standard” structure set, as well as \u0000on each of the user-defined structure sets. Results: Inter-observer \u0000variability of contours during structure segmentation was very low for clearly \u0000defined organs such as the bladder but increased for organs without \u0000well-defined borders (prostate, seminal vesicles, and rectum). For plans \u0000generated with the user-defined structure sets, strong/moderate correlations \u0000were observed between the geometric indicators for target structure agreement \u0000and target coverage for both low-risk and intermediate-risk patient groups, \u0000while OAR indicators showed no correlation to final dosimetry. Conclusions: Target delineation is crucial in order to maintain adequate dosimetric coverage \u0000regardless of the associated inter-observer uncertainties in OAR contours that \u0000had a limited impact upon final dosimetry.","PeriodicalId":14028,"journal":{"name":"International Journal of Medical Physics, Clinical Engineering and Radiation Oncology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73174115","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}

引用次数: 2

Acuros-Based Planning with Density Override for Lung SBRT by a Dynamic Conformal Arc Technique: Comparative Evaluation with AAA-Based Planning in Four-Dimensional Dose 基于acros的肺SBRT密度覆盖规划与动态适形弧技术:与基于aaa的四维剂量规划的比较评价

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology Pub Date : 2021-05-18 DOI: 10.4236/IJMPCERO.2021.102009

I. Yeo, N. Joyce, Deepinder P. Singh, M. Milano, Yuhchyau Chen, Sanjukta Bandyopadhyay, Hongmei Yang, D. Rosenzweig

{"title":"Acuros-Based Planning with Density Override for Lung SBRT by a Dynamic Conformal Arc Technique: Comparative Evaluation with AAA-Based Planning in Four-Dimensional Dose","authors":"I. Yeo, N. Joyce, Deepinder P. Singh, M. Milano, Yuhchyau Chen, Sanjukta Bandyopadhyay, Hongmei Yang, D. Rosenzweig","doi":"10.4236/IJMPCERO.2021.102009","DOIUrl":"https://doi.org/10.4236/IJMPCERO.2021.102009","url":null,"abstract":"The purpose of this study was to evaluate a planning \u0000strategy based on Acuros with density override in comparison with AAA without \u0000and with the override. Ten lung-tumor patients were selected with each PTV size \u0000around 2 - 4 cm and were imaged using slow scan, followed by four-dimensional \u0000(4D) imaging limited to the target. On each \u0000phase-specific image, gross tumor volume (GTV) was contoured. Summed \u0000over all phases, an integrated GTV (iGTV) was generated and copied to the slow \u0000scan. A treatment plan was created using a dynamic-conformal-arc technique with \u0000AAA to prescribe 60 Gy to 95% of PTV (iGTV + 0.5 cm). Each AAA-based plan was \u0000regenerated by overriding the density of the setup margin of PTV by GTV density \u0000(modeling tumor-position uncertainty). It was also regenerated with Acuros and \u0000the override. The three plans were validated in 4D dose to PTV, after similarly \u0000overriding PTV density (phase-specific), accurately calculating with Acuros, \u0000and summing the phase-specific plans through organ/dose registration. The \u0000Acuros-based plan with the override, the AAA-based plan, and the AAA-based plan \u0000with the override provided 4D PTV doses of 63.9, 67.9, and 62 Gy at D95%, \u0000respectively, averaged over all patients. The override with Acuros and AAA \u0000produced lesser 4D doses, closer to the associated 3D doses, respectively, than \u0000that without the override, with better conformity and inhomogeneity. With the \u0000override in common, Acuros provided a greater dose to PTV than that by AAA. The \u0000Acuros with the override, which was more accurate than the AAA without the \u0000override, is clinically recommended.","PeriodicalId":14028,"journal":{"name":"International Journal of Medical Physics, Clinical Engineering and Radiation Oncology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82221124","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}

引用次数: 0