المؤلفون: Rahimi, Robabeh, Taylor, Michael, Li, Xing, Chen, Kuan Ling, MacLennan, Grayden, Murdoch, Erin, Chang, Lienard, Parniani, Ashkan, Wang, Peng, Chawla, Ashish, Fan, Jiajin, Kim, Daniel

المصدر: Journal of Applied Clinical Medical Physics ; ISSN 1526-9914 1526-9914

الوصف: Purpose The treatment of brain tumors in pregnant patients poses challenges, as the out‐of‐field dose exposure to the fetus can potentially be harmful. A pregnant patient with prior radiation treatment was presented with a brain tumor at our clinic. This work reports on our pre‐treatment study that compared fetal dose exposure between intensity‐modulated proton therapy (IMPT) using pencil beam scanning (PBS) and conventional photon 3D conformal radiation therapy (3DCRT) and volumetric‐modulated arc therapy (VMAT), and the subsequent pregnant patient's radiation treatment. Materials and methods Pre‐treatment measurements of clinical plans, 3DCRT, VMAT, and IMPT, were conducted on a phantom. Measurements were performed using a device capable of neutron detections, closely following AAPM guidelines, TG158. For photon measurements, fetus shielding was utilized. On patient treatment days, which was determined to be proton treatment, shielding was used only during daily imaging for patient setup. Additionally, an in vivo measurement was conducted on the patient. Results Measurements showed that IMPT delivered the lowest fetal dose, considering both photon and neutron out‐of‐field doses to the fetus, even when shielding was implemented for photon measurements. Additionally, the proton plans demonstrated superior treatment for the mother, a reirradiation case. Conclusion The patient was treated with proton therapy, and the baby was subsequently delivered at full term with no complications. This case study supports previous clinical findings and advocates for the expanded use of proton therapy in this patient population.

الإتاحة: https://doi.org/10.1002/acm2.14394Test

المؤلفون: Xu, Qianyi, Fan, Jiajin, Vinogradskiy, Yevgeniy, Chawla, Ashish K., Kubicek, Gregory, Yang, Haihua, Huynh, Kiet, LaCouture, Tamara, Grimm, Jimm, Nie, Wei

المصدر: Journal of Applied Clinical Medical Physics ; ISSN 1526-9914 1526-9914

الوصف: Purpose To design a patient specific quality assurance (PSQA) process for the CyberKnife Synchrony system and quantify its dosimetric accuracy using a motion platform driven by patient tumor traces with rotation. Methods The CyberKnife Synchrony system was evaluated using a motion platform (MODUSQA) and a SRS MapCHECK phantom. The platform was programed to move in the superior‐inferior (SI) direction based on tumor traces. The detector array housed by the StereoPhan was placed on the platform. Extra rotational angles in pitch (head down, 4.0° ± 0.15° or 1.2° ± 0.1°) were added to the moving phantom to examine robot capability of angle correction during delivery. A total of 15 Synchrony patients were performed SBRT PSQA on the moving phantom. All the results were benchmarked by the PSQA results based on static phantom. Results For smaller pitch angles, the mean gamma passing rates were 99.75% ± 0.87%, 98.63% ± 2.05%, and 93.11% ± 5.52%, for 3%/1 mm, 2%/1 mm, and 1%/1 mm, respectively. Large discrepancy in the passing rates was observed for different pitch angles due to limited angle correction by the robot. For larger pitch angles, the corresponding mean passing rates were dropped to 93.00% ± 10.91%, 88.05% ± 14.93%, and 80.38% ± 17.40%. When comparing with the static phantom, no significant statistic difference was observed for smaller pitch angles ( p = 0.1 for 3%/1 mm), whereas a larger statistic difference was observed for larger pitch angles ( p < 0.02 for all criteria). All the gamma passing rates were improved, if applying shift and rotation correction. Conclusions The significance of this work is that it is the first study to benchmark PSQA for the CyberKnife Synchrony system using realistically moving phantoms with rotation. With reasonable delivery time, we found it may be feasible to perform PSQA for Synchrony patients with a realistic breathing pattern.

الإتاحة: https://doi.org/10.1002/acm2.14352Test

المؤلفون: Yan, Weisi, Khan, Mohammad K, Wu, Xiaodong, Simone, Charles B, Fan, Jiajin, Gressen, Eric, Zhang, Xin, Limoli, Charles L, Bahig, Houda, Tubin, Slavisa, Mourad, Waleed F

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/0vm20687Test

المؤلفون: Zhu, Xiaofeng, Nie, Wei, George, James David, Xu, Qianyi, Zheng, Dandan, Fan, Jiajin

المصدر: International Journal of Medical Physics, Clinical Engineering and Radiation Oncology ; volume 12, issue 03, page 84-97 ; ISSN 2168-5436 2168-5444

مصطلحات موضوعية: Pharmacology (medical), Complementary and alternative medicine, Pharmaceutical Science

الإتاحة: https://doi.org/10.4236/ijmpcero.2023.123008Test

المؤلفون: Sun, Pan, Jiang, Peng, Liu, Qing, Zhang, Rong, Wang, Zongkui, Cao, Haijun, Ye, Xiangzhong, Ji, Shangzhi, Han, Jinle, Lu, Kuilin, He, Xuexin, Fan, Jiajin, Cao, Dawei, Zhang, Yu, Yin, Yongsheng, Chen, Yunhua, Zhao, Xuemei, Ye, Shengliang, Su, Na, Du, Xi, Ma, Li, Li, Changqing

المساهمون: Chinese Pharmacopoeia Commission, Medical Research Program Project from Sichuan Province, CAMS Innovation Fund for Medical Sciences

المصدر: PeerJ ; volume 11, page e15698 ; ISSN 2167-8359

الوصف: Background Human parvovirus B19 (B19V) is a common contaminant found in plasma pools and plasma derivatives. Previous studies were mainly focused on limited aspects, further assessment of prevalence of B19V DNA and antibodies in plasma donors, the contamination of B19V in pooled plasma and plasma derivatives should be performed in China. Study Design and Methods Individual plasma donors’ samples from four provinces and pooled plasma from four Chinese blood product manufacturers were collected and screened using B19V DNA diagnostic kits between October 2018 and May 2020. The positive samples were investigated for the seroprevalence of B19V antibodies and subjected to sequence analysis and alignment for phylogenetic studies. Moreover, 11 plasma donors who were B19V DNA-positive at their first testing were also followed during the later donation period. Additionally, 400 plasma pools and 20 batches of plasma derivatives produced by pooled plasma with a viral load of B19V DNA exceeding 10 4 IU/mL were also collected and tested for B19V DNA and antibodies. Objectives To comprehensively and systematically determine the frequency and viral load of B19V DNA in plasma donors, pooled plasma, and plasma derivatives from four Chinese blood product manufacturers. Results A total of 17,187 plasma donors were analyzed and 44 (0.26%) specimens were found positive for B19V DNA. The quantitative DNA levels ranged from 1.01 × 10 1 to 5.09 × 10 12 IU/mL. Forty-four DNA-positive specimens were also investigated for the seroprevalence of B19V antibodies, 75.0% and 2.3% of which were seropositive for B19V IgG and IgM antibodies, respectively. The phylogenic analyses showed that the prevalent genotypes in the four provinces’ plasma donors belonged to B19V Genotype 1. Eleven individual plasma donors who were B19V DNA-positive at the first donation were then followed for a period, and in general, the DNA levels of B19V gradually decreased. Moreover, 64.8% (259/400) of the pooled plasma was contaminated by B19V, with concentrations of ...

الإتاحة: https://doi.org/10.7717/peerj.15698Test
https://peerj.com/articles/15698.pdfTest
https://peerj.com/articles/15698.xmlTest
https://peerj.com/articles/15698.htmlTest

المؤلفون: Wang, Peng, O'Grady, Fionnbarr Timothy, Janson, Martin, Kim, Daniel, Choe, Kevin S, Grayden, MacLennan, Bamberger, Caroline K, Fan, Jiajin

المصدر: J Appl Clin Med Phys ; ISSN:1526-9914

مصطلحات موضوعية: cranial titanium hardware, proton Monte Carlo dose calculation, proton SFO planning, proton beam perturbation, proton therapy

الوصف: Neurosurgical cranial titanium mesh and screws are commonly encountered in postoperative radiation therapy. However, only a limited number of reports are available in the context of proton therapy, resulting in a lack of consensus among the proton centers regarding the protocol for handling the hardware.

العلاقة: https://doi.org/10.1002/acm2.14374Test; https://pubmed.ncbi.nlm.nih.gov/38865585Test

الإتاحة: https://doi.org/10.1002/acm2.14374Test
https://pubmed.ncbi.nlm.nih.gov/38865585Test

المؤلفون: Xu, Qianyi, Vinogradskiy, Yevgeniy, Grimm, Jimm, Nie, Wei, Dupre, Pamela, Chawla, Ashish K, Bajaj, Gopal, Yang, Haihua, LaCouture, Tamara, Fan, Jiajin

المصدر: British Journal of Radiology ; volume 97, issue 1155, page 660-667 ; ISSN 0007-1285 1748-880X

مصطلحات موضوعية: Radiology, Nuclear Medicine and imaging, General Medicine

الوصف: Objectives To evaluate patient-specific quality assurance (PSQA) of 3 targets in a single delivery using a novel film-based phantom. Methods The phantom was designed to rotate freely as a sphere and could measure 3 targets with film in a single delivery. After identifying the coordinates of 3 targets in the skull, the rotation angles about the equator and meridian were computed for optimal phantom setup, ensuring the film plane intersected the 3 targets. The plans were delivered on the CyberKnife system using fiducial tracking. The irradiated films were scanned and processed. All films were analysed using 3 gamma criteria. Results Fifteen CyberKnife test plans with 3 different modalities were delivered on the phantom. Both automatic and marker-based registration methods were applied when registering the irradiated film and dose plane. Gamma analysis was performed using a 3%/1 mm, 2%/1 mm, and 1%/1 mm criteria with a 10% threshold. For the automatic registration method, the passing rates were 98.2% ± 1.9%, 94.2% ± 3.7%, and 80.9% ± 6.3%, respectively. For the marker-based registration approach, the passing rates were 96.4% ± 2.7%, 91.7% ± 4.3%, and 78.4% ± 6.2%, respectively. Conclusions A novel spherical phantom was evaluated for the CyberKnife system and achieved acceptable PSQA passing rates using TG218 recommendations. The phantom can measure true-composite dose and offers high-resolution results for PSQA, making it a valuable device for robotic radiosurgery. Advances in knowledge This is the first study on PSQA of 3 targets concurrently on the CyberKnife system.

الإتاحة: https://doi.org/10.1093/bjr/tqae011Test
https://academic.oup.com/bjr/article-pdf/97/1155/660/56794116/tqae011.pdfTest

المؤلفون: Xu, Qianyi, Huynh, Kiet, Nie, Wei, Rose, Mark S., Chawla, Ashish K., Choe, Kevin S., Kanani, Samir, Kubicek, Gregory J., Fan, Jiajin

المصدر: Journal of Applied Clinical Medical Physics ; volume 23, issue 5 ; ISSN 1526-9914 1526-9914

الوصف: The purpose of the study was to introduce and evaluate a high‐resolution diode array for patient‐specific quality assurance (PSQA) of CyberKnife brain stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT). Thirty‐three intracranial plans were retrospectively delivered on the SRS MapCHECK using fixed cone, Iris, and multileaf collimator (MLC). The plans were selected to cover a range of sites from large tumor bed, single/multiple small brain metastases (METs) to trigeminal neuralgia. Fiducial tracking using the four fiducials embedded around the detector plane was used as image guidance. Results were analyzed before and after registration based on absolute dose gamma criterion of 1 mm distance‐to‐agreement and 0.5%–3% dose‐difference. Overall, the gamma passing rates (1 mm and 3% criterion) before registration for all the patients were above 90% for all three treatment modalities (96.8 ± 3.5%, the lowest passing rate of 90.4%), and were improved after registration (99.3 ± 1.5%). When tighter criteria (1 mm and 2%) were applied, the gamma passing rates after registration for all the cases dropped to 97.3 ± 3.2%. For trigeminal neuralgia cases, we applied 1 mm and 0.5% criterion and the passing rates dropped from 100 ± 0.0% to 98.5 ± 2.0%. The mean delivery time was 33.4 ± 11.7 min, 24.0 ± 4.9 min, and 17.1 ± 2.6 min for the fixed cone, Iris, and MLC, respectively. With superior gamma passing rates and reasonable quality assurance (QA) time, we believe the SRS MapCHECK could be a good option for routine PSQA for CyberKnife SRS/SRT.

الإتاحة: https://doi.org/10.1002/acm2.13569Test

المؤلفون: Xu, Qianyi, Kubicek, Gregory, Mulvihill, David, Goldman, Warren, Eastwick, Gary, Turtz, Alan, Fan, Jiajin, Luo, Dershan

المصدر: Journal of Applied Clinical Medical Physics ; volume 22, issue 9, page 289-297 ; ISSN 1526-9914 1526-9914

الوصف: The impact of selection of prescription isodose line (IDL) on plan quality has not been well evaluated during inverse planning (IP). In this study, a total of 180 IP plans at five levels of IDL were generated for 30 brain metastases (BMs). For each BM, one round of IP was performed with typical IP settings, followed by a quick fine‐tuning to ensure the same target coverage and comparable conformality index. The impact of the IDL on the quality metrics (selectivity, gradient index [GI], and treatment time) was evaluated. The decrease of selectivity and increase of GI meant inferior target dose conformality and more dose spillage. Additionally, a metric directly correlated to the treatment time was proposed. For all cases, the mean GI decreased monotonically as IDL decreased from 70% to 30%, and the decreasing rate was significantly different based on tumor size. The mean selectivity and number of shots decreased monotonically as IDL decreased for all the tumors. From 70% to 30% IDL, the decreasing rate of the mean selectivity was 2.8% ( p = 0.020), 7.7% ( p = 0.005), and 15.4% ( p = 0.020) and that of the number of shots was 75.4% ( p = 0.001), 73.2% ( p = 0.001), and 50.7% ( p = 0.009), for the large, medium, and small tumors, respectively. For the medium and small tumor groups, the mean treatment time increased monotonically when IDLs decreased (increasing rate was 80.0% [ p = 0.002] for medium tumors [ p = 0.001] and 130.8% [ p = 0.001] for small tumors from 70% to 30%). For the large tumors, the mean treatment time was the shortest at 50% IDL (59.0 min) and higher at 70% (65.9 min) and 30% (71.9 min). Overall, the GammaPlan chose smaller sectors for plans with lower IDLs except for the large size group.

الإتاحة: https://doi.org/10.1002/acm2.13388Test

المؤلفون: O'Grady, Fionnbarr, Janson, Martin, Rao, Avani D., Chawla, Ashish K., Stephenson, Lisa, Fan, Jiajin, Wang, Peng

المصدر: Medical Physics ; volume 50, issue 4, page 1999-2008 ; ISSN 0094-2405 2473-4209

الوصف: Background Pencil beam scanning (PBS) proton therapy allows for far superior dose conformality compared with passive scattering techniques. However, one drawback of PBS is that the beam delivery time can be long, particularly when treating superficial disease. Minimizing beam delivery time is important for patient comfort and precision of treatment delivery. Mini‐ridge filters (MRF) have been shown to reduce beam delivery time for synchrotron‐based PBS. Given that cyclotron systems are widely used in proton therapy it is necessary to investigate the potential clinical benefit of mini‐ridge filters in such systems. Purpose To demonstrate the clinical benefit of using a MRF to reduce beam delivery time for patients with large target volumes and superficial disease in cyclotron‐based PBS proton therapy. Methods A MRF beam model was generated by simulating the effect of a MRF on our clinical beam data assuming a fixed snout position relative to the isocenter. The beam model was validated with a series of measurements. The model was used to optimize treatment plans in a water phantom and on six patient DICOM datasets to further study the effect of the MRF and for comparison with physician‐approved clinical treatment plans. Beam delivery time was measured for six plans with and without the MRF to demonstrate the reduction achievable. Plans with and without MRF were reviewed to confirm clinical acceptability by a radiation oncologist. Patient‐specific QA measurements were carried out with a two‐dimensional ionization chamber array detector for one representative patient's plan optimized with the MRF beam model. Results Results show good agreement between the simulated beam model and measurements with mean and maximum deviations of 0.06 mm (0.45%) and 0.61 mm (4.9%). The increase in Bragg peak width (FWHM) ranged from 2.7 mm at 226 MeV to 6.1 mm at 70 MeV. The mean and maximum reduction in beam delivery time observed per field was 29.1 s (32.2%) and 79.7 s (55.3%). Conclusion MRFs can be used to reduce ...

الإتاحة: https://doi.org/10.1002/mp.16254Test