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Salari E, Parsai EI, Shvydka D, Sperling NN. Evaluation of parameters affecting gamma passing rate in patient-specific QAs for multiple brain lesions IMRS treatments using ray-station treatment planning system. J Appl Clin Med Phys 2021; 23:e13467. [PMID: 34792850 PMCID: PMC8803291 DOI: 10.1002/acm2.13467] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/24/2021] [Accepted: 10/19/2021] [Indexed: 11/21/2022] Open
Abstract
Purpose Using intensity‐modulated radiosurgery (IMRS) with single isocenter for the treatment of multiple brain lesions has gained acceptance in recent years. One of the challenges of this technique is conducting a patient‐specific quality assurance (QA), involving accurate gamma passing rate (GPR) calculations for small and wide spread‐out targets. We evaluated effects of parameters such as dose grid and energy on GPR using our clinical IMRS plans. Methods Ten patients with total of 40 volumetric modulated arc therapy (VMAT) plans were created in Raystation (V.8A) treatment planning system (TPS) for the Varian Edge Linac using 6 and 10 flattening filter‐free (FFF) beams and planned dose grids of 1 mm and 2 mm resulting in four plans with 6–10 targets per patient. All parameters and objectives except dose grid and energy were kept the same in all plans. Next, patient‐specific QAs were measured evaluating GPR with 10% threshold, 3%/3 mm objective, and an acceptance criterion of 95%. Modulation factors (MF) and confidence intervals were calculated. Two modes of measurements, standard density (SD) and high density (HD), were used. Results Generally, plans computed with 1 mm dose grid have higher GPRs than those with 2 mm dose grid for both energies used. The GPRs of 6 FFF plans were higher than those of 10 FFF plans. GPR showed no noticeable difference between HD and SD measurements. Negative correlation between MF and GPR was observed. The HD pass rates fall within the confidence interval of SD. Conclusion Calculated dose grid should be less than or equal to one‐third of distance to agreement, thus 1 mm planned dose grid is recommended to reduce artifacts in gamma calculation. GPR of SD and HD measurement modes is almost the same, which indicates that SD mode is clinically preferable for performing patient‐specific QAs. According to our results, using 6 FFF beams with 1 mm planned dose grid is more accurate and reliable for dose calculation of IMRS plans.
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Affiliation(s)
- Elahheh Salari
- Department of Radiation Oncology, University of Toledo Medical Center, Toledo, Ohio, USA
| | - E Ishmael Parsai
- Department of Radiation Oncology, University of Toledo Medical Center, Toledo, Ohio, USA
| | - Diana Shvydka
- Department of Radiation Oncology, University of Toledo Medical Center, Toledo, Ohio, USA
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Pushpavanam K, Inamdar S, Dutta S, Bista T, Sokolowski T, Sapareto S, Rege K. Plasmonic gel nanocomposites for detection of high energy electrons. J Mater Chem B 2020; 8:4930-4939. [PMID: 32281998 DOI: 10.1039/d0tb00241k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Radiation therapy is a common treatment modality employed in the treatment of cancer. High energy photons are the primary source of radiation but when administered, they leave an exit dose resulting in radiation damage to the adjacent healthy tissues. To overcome this, high energy electrons are employed in cases of skin cancer to minimize radiation induced toxicity. Despite these advances, measurement of delivered radiation remains a challenge due to limitations with existing dosimeters including labor intensive fabrication, complex read-out techniques and post-irradiation instability. To overcome these limitations, we have developed a novel colorimetric plasmonic gel nanocomposite for the detection of therapeutic levels of radiation delivered in electron beam therapy. The plasmonic nanocomposite consists of an agarose gel matrix encapsulating precursor gold ions, which are reduced to gold nanoparticles as a result of exposure to high energy electrons. The formation of gold nanoparticles renders a change in color to the agarose matrix, resulting in the formation of plasmonic gel nanocomposites. The intensity of the color formed exhibits a linear relation with the delivered electron dose, which can be quantified using absorbance spectroscopy. The plasmonic gel nanocomposites were able to detect doses employed in fractionated electron therapy, including in an anthropomorphic phantom used for planning radiation treatments in the clinic. Furthermore, the use of glutathione as a quenching agent facilitated qualitative and quantitative spatial mapping of the delivered dose. Our results indicate that the ease of fabrication, simplicity of detection and quantification using absorbance spectroscopy, determination of spatial dose profiles, and relatively low cost make the plasmonic gel nanocomposite technology attractive for detecting electron doses in the clinic.
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Affiliation(s)
- Karthik Pushpavanam
- Chemical Engineering, Arizona State University, 501 E. Tyler Mall, ECG 303, Tempe, AZ 85287-6106 85287, USA.
| | - Sahil Inamdar
- Chemical Engineering, Arizona State University, 501 E. Tyler Mall, ECG 303, Tempe, AZ 85287-6106 85287, USA.
| | - Subhadeep Dutta
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Tomasz Bista
- Banner-MD Anderson Cancer Center, Gilbert, AZ 85234, USA
| | | | | | - Kaushal Rege
- Chemical Engineering, Arizona State University, 501 E. Tyler Mall, ECG 303, Tempe, AZ 85287-6106 85287, USA.
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Lee YK, Munawar I, Mashouf S, Sahgal A, Ruschin M. Dosimetric comparison of two treatment planning systems for spine SBRT. Med Dosim 2019; 45:77-84. [PMID: 31376988 DOI: 10.1016/j.meddos.2019.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 06/13/2019] [Accepted: 07/02/2019] [Indexed: 10/26/2022]
Abstract
Two commonly used treatment planning systems (TPS) are compared for the planning of spine stereotactic body radiotherapy (SBRT). The main purpose is to highlight relative advantages and disadvantages of each system and propose a methodologic approach for comparisons. Twenty clinical plans were inversely planned with step-and-shoot intensity-modulated radiotherapy (IMRT) each using 9 to 11 beams, referred to as IMRT_P. The prescription dose was 24 Gy in 2 fractions, and the plans were generated following our institutional protocol using the Pinnacle3 v9.2. Each case was replanned using a 2-arc volumetric modulated arc therapy (VMAT) approach, referred as VMAT_P. CT and structure sets were DICOM exported to Monaco v5.10 and planned in 2 different ways: IMRT (IMRT_M) and VMAT (VMAT_M) using the same prescription dose. Dose volume histograms (DVH) and other dose statistics of planning target volumes (PTV) and organ-at-risk (OAR) were analyzed and compared between plans. The gradient index (GI = ratio of 50% isodose volume to prescribed isodose volume) was used to measure dose fall-off outside of the PTV. Another metric - Gradient Index Inner (GIinner = the rate (in Gy/mm) - at which the dose changes from the level of the spinal cord/thecal sac toward the prescription dose) was developed and compared. All plans were considered clinically acceptable by institutional guidelines and achieved all of the OAR dose constraints. VMAT_M and IMRT_M showed comparable dose statistics for the PTV when compared to VMAT_P and IMRT_P, respectively. For IMRT plans, the median GIinner was 1.88 Gy/mm vs 1.52 Gy/mm for IMRT_M and IMRT_P respectively (p< 0.001). All other IMRT metrics were statistically similar except for the PTV maximum dose (Dmax), which was higher for IMRT_M than IMRT_P (median 30.7 Gy vs 29.0 Gy, p< 0.001). For VMAT plans, only PTV Dmin showed a statistical different between VMAT_M and VMAT_P of median 12.7 Gy vs 9.7 Gy (p< 0.001). In terms of beam sequencing parameters, the number of monitor units was statistically higher for VMAT_P compared to VMAT_M (median = 6764 vs 5376) whereas the number of segments for IMRT_M was statistically greater than IMRT_P (median = 155 vs 73). We were able to generate clinically acceptable plans for different types of spine SBRT using 2 different TPS. We used an evaluation strategy involving coverage, conformity, and dose gradient that can compared between TPS.
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Affiliation(s)
- Young Kyung Lee
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Toronto, ON M4N 3M5, Canada.
| | - Iram Munawar
- Department of Medical Physics, Trillium Health Partners, the Credit Valley Hospital, Mississauga, Canada
| | - Shahram Mashouf
- Department of Medical Physics, Marshfield Clinic Health System, Marshfield, WI 54449, USA
| | - Arjun Sahgal
- Department of Radiation Oncology, University of Toronto, Toronto, ON M4N 3M5, Canada; Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada
| | - Mark Ruschin
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Toronto, ON M4N 3M5, Canada
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Xie K, Sun H, Gao L, Sui J, Lin T, Ni X. A study on the correlation between radiation field size and gamma index passing rate for MatriXX. Medicine (Baltimore) 2019; 98:e16536. [PMID: 31348271 PMCID: PMC6709154 DOI: 10.1097/md.0000000000016536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
This study aimed to analyze the influence of the radiation field size on the passing rate of the treatment planning system using MatriXX if the field irradiated the circuit.Two sets of static fields which were 10 cm and 30 cm in the left-right direction (X), and was 31 cm to 40 cm in gun-target direction (Y) were designed. In these fields, the gantry was 0 and the monitor units were 200 MU. Two plans from an esophagus carcinoma patient with a planning target volume of 86.4 cm and a cervical carcinoma patient with a planning target volume (PTV) of 2094.1 cm were chosen. The passing rates of these plans were gained without and with protecting the circuit area from lead alloys. The gamma analysis was used and the standard was set to 3%/3 mm.The verification passing rate decreased from 95.0% to 69.2% when X was 10 cm while Y increased from 31 cm to 40 cm. With the protection from low melting point lead alloys, the passing rate was from 96.2% to 89.6%. The results of the second set of plans without lead alloys were similar but the passing rate decreased more sharply. The passing rates of the 2 patients were 99.5% and 57.1%. With the protection of the lead alloys, their passing rates were 99.8% and 72.1%, respectively.The results showed that with the increase of the radiation field size in the Y direction, more areas were irradiated in the circuit, and the passing rate gradually decreases and dropped sharply at a certain threshold. After putting lead alloys above the circuit, the passing rate was much better in the static field but was still less than 90% in the second patient volumetric modulated arc therapy (VMAT) because the circuit was irradiate in other directions. In daily QA, we should pay attention to these patients with long size tumor.
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Affiliation(s)
- Kai Xie
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Hongfei Sun
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Liugang Gao
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Jianfeng Sui
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Tao Lin
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
| | - Xinye Ni
- Department of Radiation Oncology, Changzhou No. 2 People's Hospital, Nanjing Medical University
- The Center for Medical Physics of Nanjing Medical University, Changzhou, China
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Xie K, Sun H, Lin T, Gao L, Sui J, Ni X. IMRT dose verification considering passing rate and respiratory motion. Oncol Lett 2018; 16:963-969. [PMID: 29963170 PMCID: PMC6019885 DOI: 10.3892/ol.2018.8724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 03/28/2018] [Indexed: 12/02/2022] Open
Abstract
The aim of the present study was to investigate the association between the dynamic intensity-modulated radiation therapy planned γ analysis passing rate and respiratory amplitude (A) and period (T) for different tumor volumes. A total of 30 patients with malignant lung tumors were divided into three groups: A; B; and C. The average tumor volumes (V) in the A, B and C groups were 635, 402 and 213 cm3, respectively. The simulated A values were set at 0, 5, 10, 15, 20 and 25 mm. The T values were set at 4, 5 and 6 sec. The γ analysis passing rate was calculated under different conditions (dose difference, 3%; distance difference, 3 mm). Compared with the γ analysis passing rate in the A group (A=0, static; T=4, 5, 6 sec), the γ analysis passing rate deviation (A=5 mm) was <3.3%. However, this difference was not statistically significant (P>0.05). With a gradual increase in A value, the passing rate decreased. The deviation between the 3 groups was <2.5% at the same A value (T=4, 5 and 6 sec). A descending trend of passing rate with increased A value was revealed. At the same A and T values, the passing rate decreased with decreased tumor volume. At the same tumor volume, the passing rate decreased when the A value increased. The respiratory cycle was not demonstrated to be associated with the passing rate. Overall, these results suggest that the A value should be controlled in clinical radiotherapy.
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Affiliation(s)
- Kai Xie
- Radiotherapy Department, Second People's Hospital of Changzhou, Nanjing Medical University, Changzhou, Jiangsu 213003, P.R. China
| | - Hongfei Sun
- Radiotherapy Department, Second People's Hospital of Changzhou, Nanjing Medical University, Changzhou, Jiangsu 213003, P.R. China
| | - Tao Lin
- Radiotherapy Department, Second People's Hospital of Changzhou, Nanjing Medical University, Changzhou, Jiangsu 213003, P.R. China
| | - Liugang Gao
- Radiotherapy Department, Second People's Hospital of Changzhou, Nanjing Medical University, Changzhou, Jiangsu 213003, P.R. China
| | - Jianfeng Sui
- Radiotherapy Department, Second People's Hospital of Changzhou, Nanjing Medical University, Changzhou, Jiangsu 213003, P.R. China
| | - Xinye Ni
- Radiotherapy Department, Second People's Hospital of Changzhou, Nanjing Medical University, Changzhou, Jiangsu 213003, P.R. China
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Cools RAM, Dirkx MLP, Heijmen BJM. A novel method for sub-arc VMAT dose delivery verification based on portal dosimetry with an EPID. Med Phys 2017; 44:5556-5562. [PMID: 28815696 DOI: 10.1002/mp.12518] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 06/25/2017] [Accepted: 08/04/2017] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The EPID-based sub-arc verification of VMAT dose delivery requires synchronization of the acquired electronic portal images (EPIs) with the VMAT delivery, that is, establishment of the start- and stop-MU of the acquired images. To realize this, published synchronization methods propose the use of logging features of the linac or dedicated hardware solutions. In this study, we developed a novel, software-based synchronization method that only uses information inherently available in the acquired images. METHOD The EPIs are continuously acquired during pretreatment VMAT delivery and converted into Portal Dose Images (PDIs). Sub-arcs of approximately 10 MU are then defined by combining groups of sequentially acquired PDIs. The start- and stop-MUs of measured sub-arcs are established in a synchronization procedure, using only dosimetric information in measured and predicted PDIs. Sub-arc verification of a VMAT dose delivery is based on comparison of measured sub-arc PDIs with synchronized, predicted sub-arc PDIs, using γ-analyses. To assess the accuracy of this new method, measured and predicted PDIs were compared for 20 clinically applied VMAT prostate cancer plans. The sensitivity of the method for detection of delivery errors was investigated using VMAT deliveries with intentionally inserted, small perturbations (25 error scenarios; leaf gap deviations ≤ 1.5 mm, leaf motion stops during ≤ 15 MU, linac output error ≤ 2%). RESULTS For the 20 plans, the average failed pixel rates (FPR) for full-arc and sub-arc dose QA were 0.36% ± 0.26% (1 SD) and 0.64% ± 0.88%, based on 2%/2 mm and 3%/3 mm γ-analyses, respectively. Small systematic perturbations of up to 1% output error and 1 mm leaf offset were detected using full-arc QA. Sub-arc QA was able to detect positioning errors in three leaves only during approximately 20 MU and small dose delivery errors during approximately 40 MU. In an ROC analysis, the area under the curve (AUC) for the combined full-arc/sub-arc approach was 0.90. CONCLUSIONS A novel method for sub-arc VMAT dose delivery verification with EPIDs is proposed, using only dosimetric information in acquired EPIs for synchronization. Especially in combination with full-arc QA, the established sensitivity for detection of very small errors is high, with also a high specificity.
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Affiliation(s)
- Ruud A M Cools
- Department of Radiation Oncology, Erasmus MC Cancer Institute, Groene Hilledijk 301, 3075 EA, Rotterdam, The Netherlands
| | - Maarten L P Dirkx
- Department of Radiation Oncology, Erasmus MC Cancer Institute, Groene Hilledijk 301, 3075 EA, Rotterdam, The Netherlands
| | - Ben J M Heijmen
- Department of Radiation Oncology, Erasmus MC Cancer Institute, Groene Hilledijk 301, 3075 EA, Rotterdam, The Netherlands
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Sabater S, Berenguer R, Honrubia-Gomez P, Rivera M, Nuñez A, Jimenez-Jimenez E, Martos A, Ramirez-Castillejo C. How air influences radiation dose deposition in multiwell culture plates: a Monte Carlo simulation of radiation geometry. JOURNAL OF RADIATION RESEARCH 2014; 55:1009-1014. [PMID: 24722683 PMCID: PMC4202281 DOI: 10.1093/jrr/rru022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 02/12/2014] [Accepted: 03/02/2014] [Indexed: 06/03/2023]
Abstract
Radiation of experimental culture cells on plates with various wells can cause a risk of underdosage as a result of the existence of multiple air-water interfaces. The objective of our study was to quantify this error in culture plates with multiple wells. Radiation conditions were simulated with the GAMOS code, based on the GEANT4 code, and this was compared with a simulation performed with PENELOPE and measured data. We observed a slight underdosage of ∼ 4% on the most superficial half of the culture medium. We believe that this underdosage does not have a significant effect on the dose received by culture cells deposited in a monolayer and adhered to the base of the wells.
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Affiliation(s)
- Sebastia Sabater
- Department of Radiation Oncology, Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain
| | - Roberto Berenguer
- Department of Medical Physics, Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain
| | - Paloma Honrubia-Gomez
- Centro Regional de Investigaciones Biomedicas (CRIB), Universidad de Castilla-la Mancha (UM), C/ Almansa 14, 02006 Albacete, Spain
| | - Miguel Rivera
- Department of Medical Physics, Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain
| | - Ana Nuñez
- Department of Medical Physics, Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain
| | - Esther Jimenez-Jimenez
- Department of Radiation Oncology, Hospital Son Espases, Carretera de Valldemossa 79, 07120 Palma de Mallorca, Spain
| | - Ana Martos
- Department of Radiation Oncology, Complejo Hospitalario Universitario de Albacete (CHUA), C/ Hnos Falcó 37, 02006 Albacete, Spain
| | - Carmen Ramirez-Castillejo
- Centro Regional de Investigaciones Biomedicas (CRIB), Universidad de Castilla-la Mancha (UM), C/ Almansa 14, 02006 Albacete, Spain Instituto de Salud Carlos III. Av Monforte de Lemos 5, 28029 Madrid, Spain
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