Hailey Sae Hyun Ahn, Liam Carroll, Robert Hopewell, I-Huang Tsai, Dean Jolly, Gassan Massarweh, Shirin A. Enger
{"title":"Development of small, cost-efficient scintillating fiber detectors for automated synthesis of positron emission tomography radiopharmaceuticals","authors":"Hailey Sae Hyun Ahn, Liam Carroll, Robert Hopewell, I-Huang Tsai, Dean Jolly, Gassan Massarweh, Shirin A. Enger","doi":"10.1002/mp.17369","DOIUrl":"10.1002/mp.17369","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Radiolabeling is critical in complex chemical reactions involving positron emission tomography (PET) radiotracer production. The process is now automated within a synthesis module to enhance efficiency and reduce radiation exposure. The key to this automation is the use of radiation detectors to monitor radioactivity transfer and ensure the progression of reactions. However, the high cost of these detectors has motivated the need for a more affordable alternative.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Purpose</h3>\u0000 \u0000 <p>This study aimed to develop a compact and cost-efficient detector using scintillating fibers and silicon photomultipliers (SiPMs) to track radioactivity throughout PET radiotracer production.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Monte Carlo simulations were performed with the Geant4-based M-TAG software for four detector geometries (single fiber, single fiber with bolus, 16-fiber bundle, and spiral) to optimize the detector construction for better detection efficiency. The simulations scored the energy deposited into the scintillating fibers per simulated particle, which was used to estimate the expected voltage pulse height from the SiPM considering the total light collection efficiency. Based on the simulation results, two detector configurations (16-fiber bundle and spiral fiber) were constructed using plastic scintillating fibers, optical fibers, a 6 mm <span></span><math>\u0000 <semantics>\u0000 <mo>×</mo>\u0000 <annotation>$times$</annotation>\u0000 </semantics></math> 6 mm SiPM, and commonly available electronic components. The detectors were calibrated using a Fluorine-18 (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mrow></mrow>\u0000 <mn>18</mn>\u0000 </msup>\u0000 <mi>F</mi>\u0000 </mrow>\u0000 <annotation>$^{18}{rm F}$</annotation>\u0000 </semantics></math>) source with typical activity levels used in radiotracer production. Detector performances were subsequently evaluated through linearity tests and measurement uncertainty assessments. Errors up to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 <mn>5</mn>\u0000 <mo>%</mo>\u0000 </mrow>\u0000 <annotation>$pm 5%$</annotation>\u0000 </semantics></math> were considered acceptable for","PeriodicalId":18384,"journal":{"name":"Medical physics","volume":"51 11","pages":"8454-8465"},"PeriodicalIF":3.2,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mp.17369","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142305009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jie Zhang, Chunli Luo, Wenjun Zhang, Junfang Yan, Lang Yu, Jie Qiu
{"title":"Individual curved‐needle interstitial template created using three‐dimensional printing for brachytherapy for distal parauterine tumor recurrence","authors":"Jie Zhang, Chunli Luo, Wenjun Zhang, Junfang Yan, Lang Yu, Jie Qiu","doi":"10.1002/mp.17424","DOIUrl":"https://doi.org/10.1002/mp.17424","url":null,"abstract":"BackgroundAchieving a clinically acceptable dose distribution with commercial vaginal applicators for brachytherapy of recurrent parauterine tumors is challenging. However, the application of three‐dimensional (3D) printing technology in brachytherapy has been widely acknowledged and can improve clinical treatment outcomes.PurposeThis study aimed to introduce an individual curved‐needle interstitial template (ICIT) created using 3D printing technology for high‐dose‐rate (HDR) brachytherapy with interstitial treatment to provide a clinically feasible approach to distal parauterine and vaginal cuff tumors. The entire workflow, including the design, optimization, and application, is presented.MethodsTen patients with pelvic cancer recurrence were examined at our center. The vaginal topography was filled with gauze strips soaked in developer solution, and images were obtained using computed tomography (CT) and magnetic resonance imaging (MRI). Curved needle paths were designed, and ICITs were 3D‐printed according to the high‐risk clinical target volume (HRCTV) and vaginal filling model. The dose and volume histogram parameters of the HRCTV (<jats:italic>V</jats:italic><jats:sub>100</jats:sub>, <jats:italic>V</jats:italic><jats:sub>200</jats:sub>, <jats:italic>D</jats:italic><jats:sub>90</jats:sub>, and <jats:italic>D</jats:italic><jats:sub>98</jats:sub>) and organs at risk (OARs) (<jats:italic>D</jats:italic><jats:sub>2cc</jats:sub>) were recorded.ResultsAll patients completed interstitial brachytherapy treatment with the 3D‐printed ICIT. One patient experienced vaginal cuff tumor recurrence, and nine patients experienced parametrial tumor recurrence (four on the left and five on the right). We used two to five interstitial needles, and the maximum angle of the curved needle was 40°. No source obstruction events occurred during treatment of these 10 patients. The doses delivered to the targets and OARs of all patients were within the dose limits and based on clinical experience at our center.ConclusionThe ICIT is a treatment option for patients with distal parauterine tumor recurrence. This method addresses the limitations of vaginal intracavitary and standard interstitial applicators. The ICIT has the advantages of biocompatibility, personalization, and magnetic resonance imaging compatibility.","PeriodicalId":18384,"journal":{"name":"Medical physics","volume":"37 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142251216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Long‐term beam output stability of an accelerator‐based boron neutron capture therapy system","authors":"Shinya Komori, Akihiko Takeuchi, Ryohei Kato, Yuhei Yamazaki, Tomoaki Motoyanagi, Yuki Narita, Takahiro Kato, Yoshihiro Takai","doi":"10.1002/mp.17426","DOIUrl":"https://doi.org/10.1002/mp.17426","url":null,"abstract":"BackgroundAccelerator‐based boron neutron capture therapy (AB‐BNCT) systems are becoming commercially available and are expected to be widely used in hospitals. To ensure the safety of BNCT, establishing a quality assurance (QA) program and properly managing the stability of the system are necessary. In particular, a high level of beam output stability is required to avoid accidents because beam output is a major factor in patient dose. However, no studies have analyzed the long‐term beam output stability of AB‐BNCT systems.PurposeThis study aimed to retrospectively analyze the long‐term stability of the beam output by statistical process control (SPC) based on the QA results over 3 years.MethodsThe data analyzed are the results of daily QA (DQA) and weekly QA (WQA) in an AB‐BNCT system and were taken between June 2020 and September 2023. The evaluation of the stability of the beam output was based on the reaction rate between gold and neutrons calculated using the activation foil method using a gold foil. In DQA, which can be performed in a short time, the gold foil was applied directly to the beam irradiation aperture in air. In WQA, measurements were performed at the phantom surface, 2‐cm depth, and 6‐cm depth using a dedicated water phantom. The acquired data were retrospectively analyzed by individuals and a moving range chart (I‐MR chart), exponentially weighted moving average control chart (EWMA chart), and several process capability indexes (PCIs).ResultsOver 99% of the DQA I‐MR chart results were within control limits, whereas the WQA I‐MR chart results showed that 1.8%, 4.1%, and 2.0% of the measurements exceeded the control limits at the surface, 2‐cm depth, and 6‐cm depth, respectively. The variation in the reaction rate of the gold foil before and after the replacement of the target was <0.5%. The EWMA chart results revealed no significant beam output drift for either DQA or WQA. Most measured data were normal based on the results of the Anderson–Darling test and met the requirements for PCI evaluation; most PCI values were >1.0; however, the <jats:italic>C</jats:italic><jats:sub>pmk</jats:sub> of DQA and the 2‐ and 6‐cm depth WQAs between August 2021 and November 2022 in treatment course 2 were 0.83, 0.77, and 0.87, respectively, which were <1.0.ConclusionsThe long‐term stability of beam output was confirmed using SPC in an AB‐BNCT system. The results of the control chart revealed no significant variation or drift in the beam output, and the quantitative evaluation using PCI revealed high stability. A routine QA program will enable us to provide safe BNCT.","PeriodicalId":18384,"journal":{"name":"Medical physics","volume":"14 1","pages":""},"PeriodicalIF":3.8,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142251218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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