Journal of Medical Physics最新文献

{"title":"Program for Determining the Dosimetric Contribution of Tc-99m Biokinetics in Estimating the Dose to the Heart of a Male Adult.","authors":"Rosa Adela Morales-Nizama, Moisés Miguel Gallozzo-Cárdenas, Héctor Almanzor Chinchay-Espino, Emzon Murga-Torres, Amilu M Alvarez-Escobedo, Renny Nazario-Naveda","doi":"10.4103/jmp.jmp_79_23","DOIUrl":"10.4103/jmp.jmp_79_23","url":null,"abstract":"<p><strong>Purpose: </strong>To calculate the contribution of absorbed dose by organs in the biokinetics of Tc-99m when used for radiodiagnosis of the adult male heart employing a Matlab program.</p><p><strong>Methods: </strong>The absorbed self-dose of the adult male heart and absorbed dose by organs in the biokinetics of the heart when administering Tc-99m are estimated using the MIRD formalism and the Cristy-Eckerman representation, which have been employed to develop the algorithm in Matlab.</p><p><strong>Results: </strong>The results indicate that electron capture emissions of 1.446 (mGy/MBq) and Auger electrons of 0.062 (mGy/MBq) are entirely directed towards the target organ (heart) and contribute 29.33% and 1.25% respectively to its total dose. Additionally, the dosimetric contributions of biokinetic organs correspond to characteristic radiation emissions and gamma photons at 2.578 (mGy/MBq) for Tc-99m, representing 52.29% of its total dose.</p><p><strong>Conclusion: </strong>These dosimetric contributions are significant in estimating the total absorbed dose by the heart in adult males and should not be disregarded.</p>","PeriodicalId":51719,"journal":{"name":"Journal of Medical Physics","volume":"49 1","pages":"1-5"},"PeriodicalIF":0.9,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11141756/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141201119","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}

{"title":"PAHPhysRAD: A Digital Imaging and Communications in Medicine Research Tool for Segmentation and Radiomic Feature Extraction.","authors":"Daniel Arrington, Ryan Motley, Zachery Morton Colbert, Margot Lehman, Prabhakar Ramachandran","doi":"10.4103/jmp.jmp_120_23","DOIUrl":"10.4103/jmp.jmp_120_23","url":null,"abstract":"<p><strong>Introduction: </strong>Segmentation and analysis of organs at risks (OARs) and tumor volumes are integral concepts in the development of radiotherapy treatment plans and prediction of patients' treatment outcomes.</p><p><strong>Aims: </strong>To develop a research tool, PAHPhysRAD, that can be used to semi- and fully automate segmentation of OARs. In addition, the proposed software seeks to extract 3214 radiomic features from tumor volumes and user-specified dose-volume parameters.</p><p><strong>Materials and methods: </strong>Developed within MATLAB, PAHPhysRAD provides a comprehensive suite of segmentation tools, including manual, semi-automatic, and automatic options. For semi-autosegmentation, meta AI's Segment Anything Model was incorporated using the bounding box methods. Autosegmentation of OARs and tumor volume are implemented through a module that enables the addition of models in Open Neural Network Exchange format. To validate the radiomic feature extraction module in PAHPhysRAD, radiomic features extracted from gross tumor volume of 15 non-small cell lung carcinoma patients were compared against the features extracted from 3D Slicer™. The dose-volume parameters extraction module was validated using the dose volume data extracted from 28 tangential field-based breast treatment planning datasets. The volume receiving ≥20 Gy (V20) for ipsilateral lung and the mean doses received by the heart and ipsilateral lung, were compared against the parameters extracted from Eclipse.</p><p><strong>Results: </strong>The Wilcoxon signed-rank test revealed no significant difference between the majority of the radiomic features derived from PAHPhysRAD and 3D Slicer. The average mean lung and heart doses calculated in Eclipse were 5.51 ± 2.28 Gy and 1.64 ± 1.98 Gy, respectively. Similarly, the average mean lung and heart doses calculated in PAHPhysRAD were 5.45 ± 2.89 Gy and 1.67 ± 2.08 Gy, respectively.</p><p><strong>Conclusion: </strong>The MATLAB-based graphical user interface, PAHPhysRAD, offers a user-friendly platform for viewing and analyzing medical scans with options to extract radiomic features and dose-volume parameters. Its versatility, compatibility, and potential for further development make it an asset in medical image analysis.</p>","PeriodicalId":51719,"journal":{"name":"Journal of Medical Physics","volume":"49 1","pages":"12-21"},"PeriodicalIF":0.9,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11141757/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141201171","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}

{"title":"Single- versus Multi-computed Tomography Simulation for High-dose-rate Postoperative Gynecological Intracavitary Brachytherapy.","authors":"Angeliki Douvara, Nikolaos Kollaros, Georgios Patatoukas, Marina Chalkia, Efrosini Kypraiou, Nikolaos Trogkanis, Vassileios Kouloulias, Kalliopi Platoni","doi":"10.4103/jmp.jmp_130_23","DOIUrl":"10.4103/jmp.jmp_130_23","url":null,"abstract":"<p><strong>Introduction: </strong>This study aimed to investigate whether there is a dosimetric difference of implementing single instead of multi-computed tomography (CT) simulation treatment planning for high-dose-rate postoperative gynecological intracavitary brachytherapy (BT).</p><p><strong>Materials and methods: </strong>Eighty patients were registered in the study. They received three BT fractions of 7 Gy/week (three CTs, three original plans). The organs at risk (OAR), the rectal wall, and the clinical target volume (CTV) were delineated. The delivered doses for the 2cc of OARs (D_2cc), 1cc of rectal wall (D_1cc), as well as for the 90% and 100% of CTV volume (D_CTV90%, D_CTV100%) were evaluated. To evaluate the values of the above parameters if the single-CT-simulation method has been chosen, the time of the first treatment plan was corrected for the decay and applied as the second and third CT, retrospectively, creating the next fractions (two revised plans).</p><p><strong>Results: </strong>No statistically significant (<i>P</i> > 0.05) differences were found between the original and revised plans for the OARs and CTV. However, for the single-CT-simulation method, it was noted that the dose constraints for the total rectal dose were exceeded in some cases (36.3%).</p><p><strong>Conclusion: </strong>The fact that rectal dose constraints were exceeded in 1/3 of patients with the single-CT-simulation method is dosimetrically significant.</p>","PeriodicalId":51719,"journal":{"name":"Journal of Medical Physics","volume":"49 1","pages":"6-11"},"PeriodicalIF":0.9,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11141752/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141201131","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}

{"title":"A Practical Method for Slice Spacing Measurement Using the American Association of Physicists in Medicine Computed Tomography Performance Phantom.","authors":"Choirul Anam, Ariij Naufal, Yanurita Dwihapsari, Toshioh Fujibuchi, Geoff Dougherty","doi":"10.4103/jmp.jmp_155_23","DOIUrl":"10.4103/jmp.jmp_155_23","url":null,"abstract":"<p><strong>Background: </strong>The slice spacing has a crucial role in the accuracy of computed tomography (CT) images in sagittal and coronal planes. However, there is no practical method for measuring the accuracy of the slice spacing.</p><p><strong>Purpose: </strong>This study proposes a novel method to automatically measure the slice spacing using the American Association of Physicists in Medicine (AAPM) CT performance phantom.</p><p><strong>Methods: </strong>The AAPM CT performance phantom module 610-04 was used to measure slice spacing. The process of slice spacing measurement involves a pair of axial images of the module containing ramp aluminum objects located at adjacent slice positions. The middle aluminum plate of each image was automatically segmented. Next, the two segmented images were combined to produce one image with two stair objects. The centroid coordinates of two stair objects were automatically determined. Subsequently, the distance between these two centroids was measured to directly indicate the slice spacing. For comparison, the slice spacing was calculated by accessing the slice position attributes from the DICOM header of both images. The proposed method was tested on phantom images with variations in slice spacing and field of view (FOV).</p><p><strong>Results: </strong>The results showed that the automatic measurement of slice spacing was quite accurate for all variations of slice spacing and FOV, with average differences of 9.0% and 9.3%, respectively.</p><p><strong>Conclusion: </strong>A new automated method for measuring the slice spacing using the AAPM CT phantom was successfully demonstrated and tested for variations of slice spacing and FOV. Slice spacing measurement may be considered an additional parameter to be checked in addition to other established parameters.</p>","PeriodicalId":51719,"journal":{"name":"Journal of Medical Physics","volume":"49 1","pages":"103-109"},"PeriodicalIF":0.9,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11141755/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141200656","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}

{"title":"External Beam Radiotherapy in High-risk Head-and-neck Cancers with Reduced Overall Treatment Time in Telecobalt Beam Quality.","authors":"Ramamoorthy Ravichandran, R Ravi Kannan","doi":"10.4103/jmp.jmp_142_23","DOIUrl":"10.4103/jmp.jmp_142_23","url":null,"abstract":"","PeriodicalId":51719,"journal":{"name":"Journal of Medical Physics","volume":"48 4","pages":"409-411"},"PeriodicalIF":0.9,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10783190/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139467314","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}

{"title":"Split X-jaw Planning Technique of Volumetric Modulated Arc Radiotherapy.","authors":"Jyotiman Nath, Gautam Sarma","doi":"10.4103/jmp.jmp_67_23","DOIUrl":"10.4103/jmp.jmp_67_23","url":null,"abstract":"<p><p>This brief communication article examines the constraints posed by the Varian linear accelerator machine's volumetric-modulated arc therapy (VMAT) due to the maximum extent of the multileaf collimator (MLC) in the x-jaw direction. The MLC leaves within this machine are capable of extending up to 15 cm in the x-jaw direction. However, when VMAT is employed with excessive extension, modulation level decreases, leading to compromised target dose distribution, and the protection of critical organs. The existing VMAT techniques involve open and limited x-jaw approaches, but these methods present avenues for enhancement. One innovative approach is the split x-jaw planning technique, which involves segmenting the open field into two distinct fields with some overlap. This strategy yields four treatment arcs that comprehensively cover the planning target volume (PTV). Enhancing modulation and conformity can be achieved by restricting each field's size to 15 cm. Consequently, this technique demonstrates improved target dose distributions, heightened plan conformity, and more effective sparing of organs at risk compared to the limited and open methodologies. Initial dosimetric studies suggest that the split X-jaw technique holds promise as a superior planning solution for larger PTVs that exceed the MLC's maximum x-jaw extent.</p>","PeriodicalId":51719,"journal":{"name":"Journal of Medical Physics","volume":"48 4","pages":"398-401"},"PeriodicalIF":0.7,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10783193/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139467328","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}

{"title":"Clinical Utility of Arterial Spin Labeling Magnetic Resonance Imaging in the Evaluation of the Brain.","authors":"Harshavardhan Pobbati, Sumit Kumar Ghosh, Deeksha Gautam","doi":"10.4103/jmp.jmp_64_23","DOIUrl":"10.4103/jmp.jmp_64_23","url":null,"abstract":"<p><strong>Introduction: </strong>Cerebral blood flow (CBF) is essential for studying the brain in both normal and diseased states. Arterial spin labeling (ASL) is a functional magnetic resonance imaging (MRI) technique that uses arterial water as an endogenous tracer to measure CBF, thus does not require an injection of exogenous tracers and is noninvasive and can therefore be used to track changes in CBF.</p><p><strong>Materials and methods: </strong>This prospective, observational and descriptive study was done at the department of imaging, Maxcure Hospital, Hyderabad, for the duration of 18 months. All studies were performed on a 1.5T Philips Prodiva CX using a phased array coil.</p><p><strong>Results: </strong>A prospective observational and descriptive study was done among 100 patients to study the clinical utility of ASL. Out of 100 patients, 20 (20%) patients showed normal MRI findings. Rest 80 (80%) patients had abnormal MRI findings.</p><p><strong>Conclusion: </strong>ASL provides additional and complementary information to that available from structural MRI in all categories of abnormalities.</p>","PeriodicalId":51719,"journal":{"name":"Journal of Medical Physics","volume":"48 4","pages":"378-383"},"PeriodicalIF":0.9,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10783186/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139467191","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}

{"title":"Dosimetric Comparison of Unmatched Flattening Filter-free and Flattened Beams in Volumetric Arc Therapy Plans for Head-and-neck Cancer.","authors":"Arvind Kumar, Kiran Sharma, Chandi Prasad Bhatt, Abhishek Garg","doi":"10.4103/jmp.jmp_68_23","DOIUrl":"10.4103/jmp.jmp_68_23","url":null,"abstract":"<p><strong>Introduction: </strong>Conventionally, the fattened beam is being used in radiotherapy for routine clinical cases even after introduction of intensity-modulated radiotherapy with incorporation of multi-leaf collimator system. With the removal of the flattening filter (FF) from the beam's path average energy of the photon gets reduced resulting in reduced scatter, reduction in treatment time, and reduced neutron contamination for high-energy beam and ultimately resulting in treatment plan quality deviations. This study aims to investigate the usefulness of the FF-free (FFF) beam for routine head-and-neck cancer (HNC) cases treated with volumetric arc therapy (VMAT) and dosimetrically compares the result with the FF beam.</p><p><strong>Materials and methods: </strong>In this study, 20 patients treated on Halcyon^TM (unmatched 6 megavoltage [6MV] FFF beam) medical linear accelerator with VMAT of different HNC selected and for comparison with 6MV FF beam, 20 equivalent treatment plans are created for Truebeam^TM configuration and the plans have been evaluated for target coverage, doses to the organ at risk (OAR), and other dose quality indices.</p><p><strong>Results: </strong>Comparable target coverage, doses to OARs except for rest right parotid (<i>P</i> = 0.02) between 6MV FFF beam and 6MV FF beam is observed. Insignificant differences in conformity index, homogeneity index, and gradient index have been observed. Higher monitor unit (MU) (<i>P</i> ≤ 0.001) and lesser beam on time (BOT) (<i>P</i> = 0.003) have been observed in 6MV FFF.</p><p><strong>Conclusion: </strong>6MV FFF beam provides comparable target coverage and improved dose-sparing effect to most of the OARs. 6MV FFF beam has lesser BOT, but on the other hand number of MUs is higher as compared to 6MV-FF plans.</p>","PeriodicalId":51719,"journal":{"name":"Journal of Medical Physics","volume":"48 4","pages":"338-344"},"PeriodicalIF":0.9,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10783192/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139467199","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}

{"title":"Overcoming Problems Caused by Offset Distance of Multiple Targets in Single-isocenter Volumetric Modulated Arc Therapy Planning for Stereotactic Radiosurgery.","authors":"Takaaki Ito, Kazuki Kubo, Hajime Monzen, Yuya Yanagi, Kenji Nakamura, Yusuke Sakai, Yasumasa Nishimura","doi":"10.4103/jmp.jmp_8_23","DOIUrl":"10.4103/jmp.jmp_8_23","url":null,"abstract":"<p><strong>Purpose: </strong>The purpose of the study is to investigate the impact of large target offset distances on the dose distribution and gamma passing rate (GPR) in single-isocenter multiple-target stereotactic radiosurgery (SIMT SRS) using volumetric modulated arc therapy (VMAT) with a flattening filter-free (FFF) beam from a linear accelerator.</p><p><strong>Methods: </strong>Two targets with a diameter of 1 cm were offset by \"±2, ±4, and ±6 cm from the isocenter in a verification phantom for head SRS (20 Gy/fr). The VMAT plans were created using collimator angles that ensured the two targets did not share a leaf pair from the multi-leaf collimator. To evaluate the low-dose spread intermediate dose spill (R_50%), GPRs were measured with a criterion of 3%/2 mm using an electronic portal imaging device and evaluated using monitor unit (MU), modulation complexity score for VMAT (MCS_v), and leaf travel (LT) parameters.</p><p><strong>Results: </strong>For offsets of 2, 4, and 6 cm, the respective parameters were: R_50%, 4.75 ± 0.36, 5.13 ± 0.36, and 5.11 ± 0.33; GPR, 95.01%, 93.82%, and 90.67%; MU, 5893 ± 186, 5825 ± 286, and 5810 ± 396; MCS_v, 0.24, 0.16, and 0.13; and LT, 189.21 ± 36.04, 327.69 ± 67.01, and 430.39 ± 114.34 mm. There was a spread in the low-dose region from offsets of ≥4 cm and the GPR negatively correlated with LT (<i>r</i> = -0.762). There was minimal correlation between GPR and MU or MCS_v.</p><p><strong>Conclusions: </strong>In SIMT SRS VMAT plans with an FFF beam from a linear accelerator, target offsets of <4 cm from the isocenter can minimize the volume of the low-dose region receiving 10 Gy or more. During treatment planning, it is important to choose gantry, couch, and collimator angles that minimize LT and thereby improve the GPR.</p>","PeriodicalId":51719,"journal":{"name":"Journal of Medical Physics","volume":"48 4","pages":"365-372"},"PeriodicalIF":0.9,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10783189/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139467639","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}

{"title":"Historical Progress of Stereotactic Radiation Surgery.","authors":"Navid Khaledi, Rao Khan, James L Gräfe","doi":"10.4103/jmp.jmp_62_23","DOIUrl":"10.4103/jmp.jmp_62_23","url":null,"abstract":"<p><p>Radiosurgery and stereotactic radiotherapy have established themselves as precise and accurate areas of radiation oncology for the treatment of brain and extracranial lesions. Along with the evolution of other methods of radiotherapy, this type of treatment has been associated with significant advances in terms of a variety of modalities and techniques to improve the accuracy and efficacy of treatment. This paper provides a comprehensive overview of the progress in stereotactic radiosurgery (SRS) over several decades, and includes a review of various articles and research papers, commencing with the emergence of stereotactic techniques in radiotherapy. Key clinical aspects of SRS, such as fixation methods, radiobiology considerations, quality assurance practices, and treatment planning strategies, are presented. In addition, the review highlights the technological advancements in treatment modalities, encompassing the transition from cobalt-based systems to linear accelerator-based modalities. By addressing these topics, this study aims to offer insights into the advancements that have shaped the field of SRS, that have ultimately enhanced the accuracy and effectiveness of treatment.</p>","PeriodicalId":51719,"journal":{"name":"Journal of Medical Physics","volume":"48 4","pages":"312-327"},"PeriodicalIF":0.9,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10783188/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139467317","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}