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Zhang YZ, Liang XJ, Dong YQ, Li CY, Zhao ZR. Evaluation indices of the temperature difference of subgrade and the optimization of mitigation measures in cold regions. Heliyon 2023; 9:e17526. [PMID: 37455961 PMCID: PMC10345257 DOI: 10.1016/j.heliyon.2023.e17526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 05/22/2023] [Accepted: 06/20/2023] [Indexed: 07/18/2023] Open
Abstract
With the construction and operation of railways in cold regions, the asymmetric deformation of subgrades due to the difference in the transverse ground temperature has become a prominent issue. A comprehensive evaluation of the transverse ground temperature difference and investigation of the corresponding mitigation measures should be conducted to avoid or minimize the damage resulting from this difference, thereby improving subgrade stability and reducing deformation. In this study, the time history variations in the homogeneity and symmetry indices of the ground temperature at typical instances that reflect the spatial and temporal changes in the temperature difference of the subgrade were proposed as evaluation indices. The feasibility of these evaluation indices was verified through numerical models with different types of anti-frost berms. Subsequently, the numerical models were used to analyze the ground temperature evaluation indices of a subgrade with expanded polystyrene (EPS) insulation board and polyurethane (PU) insulation board at different locations. Additionally, the performances of each mitigation measure in eliminating or reducing the ground temperature difference were assessed and compared. The results show that all the mitigation measures could improve the homogeneity and symmetry of the ground temperature distribution. The maximum mitigation rates for the homogeneity and symmetry are 97.87% and 45.90%, respectively. This study provides a comprehensive evaluation method for the temperature difference of subgrades constructed in cold regions and a theoretical reference for the selection of anti-frost measures in the design, operation, and maintenance of subgrades in cold regions.
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Affiliation(s)
- Yu-zhi Zhang
- Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
- Collaborative Innovation Center for Performance and Safety of Large-scale Infrastructure, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
| | - Xiao-jie Liang
- China Railway Sixth Bureau Group, Shijiazhuang Railway Construction Co., Ltd., Shijiazhuang, 050010, China
- School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
| | - Ya-qian Dong
- School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
| | - Cheng-yan Li
- School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
| | - Zhi-rong Zhao
- Shuohuang Railway Development Co., Ltd., Suning 062350, China
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Das IJ, Yadav P, Andersen AD, Chen ZJ, Huang L, Langer MP, Lee C, Li L, Popple RA, Rice RK, Schiff PB, Zhu TC, Abazeed ME. Dose prescription and reporting in stereotactic body radiotherapy: A multi-institutional study. Radiother Oncol 2023; 182:109571. [PMID: 36822361 PMCID: PMC10121952 DOI: 10.1016/j.radonc.2023.109571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 02/07/2023] [Accepted: 02/12/2023] [Indexed: 02/23/2023]
Abstract
BACKGROUND AND PURPOSE Radiation dose prescriptions are foundational for optimizing treatment efficacy and limiting treatment-related toxicity. We sought to assess the lack of standardization of SBRT dose prescriptions across institutions. MATERIALS & METHODS Dosimetric data from 1298 patients from 9 academic institutions treated with IMRT and VMAT were collected. Dose parameters D100, D98, D95, D50, and D2 were used to assess dosimetric variability. RESULTS Disease sites included lung (48.3 %) followed by liver (29.7 %), prostate (7.5 %), spine (6.8 %), brain (4.1 %), and pancreas (2.5 %). The PTV volume in lung varied widely with bimodality into two main groups (22.0-28.7 cm3) and (48.0-67.1 cm3). A hot spot ranging from 120-150 % was noted in nearly half of the patients, with significant variation across institutions. A D50 ≥ 110 % was found in nearly half of the institutions. There was significant dosimetric variation across institutions. CONCLUSIONS The SBRT prescriptions in the literature or in treatment guidelines currently lack nuance and hence there is significant variation in dose prescriptions across academic institutions. These findings add greater importance to the identification of dose parameters associated with improved clinical outcome comparisons as we move towards more hypofractionated treatments. There is a need for standardized reporting to help institutions in adapting treatment protocols based on the outcome of clinical trials. Dosimetric parameters are subsequently needed for uniformity and thereby standardizing planning guidelines to maximize efficacy, mitigate toxicity, and reduce treatment disparities are urgently needed.
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Affiliation(s)
- Indra J Das
- Department of Radiation Oncology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - Poonam Yadav
- Department of Radiation Oncology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Aaron D Andersen
- Department of Radiation Oncology, Renown Medical Center, Reno, NV, USA
| | - Zhe Jay Chen
- Department of Therapeutic Radiology, Yale University, New haven, CT, USA
| | - Long Huang
- Department of Radiation Oncology, University of Utah, Salt Lake City, UT, USA
| | - Mark P Langer
- Department of Radiation Oncology, Indiana University Health, Indianapolis, IN, USA
| | - Choonik Lee
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Lin Li
- Division of Biostatistics, Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Richard A Popple
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Roger K Rice
- Department of Radiation Medicine and Applied Science, University of California, San Diego, CA, USA
| | - Peter B Schiff
- Department of Radiation Oncology, New York University Grossman School of Medicine, New York, NY, USA
| | - Timothy C Zhu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Mohamed E Abazeed
- Department of Radiation Oncology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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Akbari F, Taghizadeh S, Pearson D. A retrospective study to establish recommendations for plan quality metrics in Lung SBRT. Med Dosim 2021; 47:111-116. [PMID: 34973881 DOI: 10.1016/j.meddos.2021.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/27/2021] [Indexed: 10/19/2022]
Abstract
The increased use of Stereotactic body radiation therapy (SBRT) has warranted a new method of plan evaluation. The crucial component of SBRT is the precise, conformal delivery of radiation dose to the target with rapid dose fall-off in the surrounding normal tissues.In this study, we retrospectively evaluated plan quality in lung SBRT patients by calculating conformity, homogeneity, and gradient parameters using an in-house script. The goal of this study was to establish achievable, size-dependent recommendations for these plan quality metrics such that they may be used as a guideline in our clinic. Seventy-three patients treated with lung SBRT at The University of Toledo Medical Center during the period 2017-2020 were retrospectively reviewed for this study. Plans were evaluated using dosimetric indices from respective The Radiation Therapy Oncology Group (RTOG) and International Commission on Radiation Units and Measurements (ICRU) protocols. Average values for each of the following indices were calculated: RTOG conformity index = 1.12 ± 0.13; Paddick conformity index = 0.82 ± 0.07; gradient index = 4.63 ± 0.71; and Homogeneity index = 0.3 ± 0.07, for all studied lung lesions with a mean volume of 23.2 cc. Our final recommendations are based on clinically approved plans, after having removed statistical outliers that we may not have approved had the metrics been calculated. Additionally, we observed that a sharper dose fall-off and a more homogeneous plan were found using 6 FFF compared to 10 FFF energy. Comparison between our results and RTOG0915 data shows no deviation or minor deviation for the RTOG conformity index and the ratio of 50% prescription isodose volume to the target volume. Furthermore, no statistically significant correlation between RTOG conformity index and target volume was observed which is in agreement with RTOG0915. Using various dosimetric indices to characterize dose distributions in lung SBRT is a powerful tool to assess plan quality. We recommend that these values be calculated for all plans, utilizing a script or program so as to improve clinical workflow.
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Affiliation(s)
- Fatemeh Akbari
- Department of Radiation Oncology, University of Toledo Health Science Campus, Toledo, OH, 43614 USA
| | - Somayeh Taghizadeh
- Department of Radiation Oncology, University of Toledo Health Science Campus, Toledo, OH, 43614 USA
| | - David Pearson
- Department of Radiation Oncology, University of Toledo Health Science Campus, Toledo, OH, 43614 USA.
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Hellerbach A, Eichner M, Rueß D, Luyken K, Hoevels M, Judge M, Baues C, Ruge M, Kocher M, Treuer H. Impact of prescription isodose level and collimator selection on dose homogeneity and plan quality in robotic radiosurgery. Strahlenther Onkol 2021; 198:484-496. [PMID: 34888732 PMCID: PMC9038902 DOI: 10.1007/s00066-021-01872-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 10/17/2021] [Indexed: 11/28/2022]
Abstract
Purpose In stereotactic radiosurgery (SRS), prescription isodoses and resulting dose homogeneities vary widely across different platforms and clinical entities. Our goal was to investigate the physical limitations of generating dose distributions with an intended level of homogeneity in robotic SRS. Methods Treatment plans for non-isocentric irradiation of 4 spherical phantom targets (volume 0.27–7.70 ml) and 4 clinical targets (volume 0.50–5.70 ml) were calculated using Sequential (phantom) or VOLOTM (clinical) optimizers (Accuray, Sunnyvale, CA, USA). Dose conformity, volume of 12 Gy isodose (V12Gy) as a measure for dose gradient, and treatment time were recorded for different prescribed isodose levels (PILs) and collimator settings. In addition, isocentric irradiation of phantom targets was examined, with dose homogeneity modified by using different collimator sizes. Results Dose conformity was generally high (nCI ≤ 1.25) and varied little with PIL. For all targets and collimator sets, V12Gy was highest for PIL ≥ 80% and lowest for PIL ≤ 65%. The impact of PIL on V12Gy was highest for isocentric irradiation and lowest for clinical targets (VOLOTM optimization). The variability of V12Gy as a function of collimator selection was significantly higher than that of PIL. V12Gy and treatment time were negatively correlated. Plans utilizing a single collimator with a diameter in the range of 70–80% of the target diameter were fastest, but showed the strongest dependence on PIL. Conclusion Inhomogeneous dose distributions with PIL ≤ 70% can be used to minimize dose to normal tissue. PIL ≥ 90% is associated with a marked and significant increase in off-target dose exposure. Careful selection of collimators during planning is even more important. Supplementary Information The online version of this article (10.1007/s00066-021-01872-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexandra Hellerbach
- Faculty of Medicine and University Hospital Cologne, Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany.
| | - Markus Eichner
- Faculty of Medicine and University Hospital Cologne, Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany
| | - Daniel Rueß
- Faculty of Medicine and University Hospital Cologne, Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany
| | - Klaus Luyken
- Faculty of Medicine and University Hospital Cologne, Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany
| | - Mauritius Hoevels
- Faculty of Medicine and University Hospital Cologne, Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany
| | - Michael Judge
- Faculty of Medicine and University Hospital Cologne, Institute of Radiation Oncology, University of Cologne, Cologne, Germany
| | - Christian Baues
- Faculty of Medicine and University Hospital Cologne, Institute of Radiation Oncology, University of Cologne, Cologne, Germany
| | - Maximilian Ruge
- Faculty of Medicine and University Hospital Cologne, Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany
| | - Martin Kocher
- Faculty of Medicine and University Hospital Cologne, Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany
| | - Harald Treuer
- Faculty of Medicine and University Hospital Cologne, Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Kerpener Straße 62, 50937, Cologne, Germany
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Dahshan BA, Weir JS, Bice RP, Renz P, Cifarelli DT, Poplawski L, Hack J, Vargo JA, Cifarelli CP. Dose homogeneity analysis of adjuvant radiation treatment in surgically resected brain metastases: Comparison of IORT, SRS, and IMRT indices. Brachytherapy 2021; 20:426-432. [PMID: 33454200 DOI: 10.1016/j.brachy.2020.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/10/2020] [Accepted: 11/10/2020] [Indexed: 10/22/2022]
Abstract
PURPOSE Although surgery remains a treatment option for symptomatic brain metastases, the need for adjuvant radiation after surgery is widely accepted as standard. Despite a multitude of randomized trials aimed at identifying the ideal radiation treatment plan for surgically resected metastases, the development of new delivery regiments necessitates a periodic re-evaluation of dosimetric performance/outcome. Here, we compare the homogeneity index (HI) across three platforms: single-session stereotactic radiosurgery (SRS), multisession stereotactic radiotherapy, and intraoperative radiotherapy (IORT). METHODS AND MATERIALS Patients treated with IORT after surgical resection of brain metastases were identified and dosimetric parameters collected from the dose-volume histograms based on the development of conformal plans for adjuvant radiation using Gamma Knife-SRS (GK-SRS), linear accelerator based intensity-modulated radiation therapy, and IORT. HIs were calculated using four established methods and compared across platforms within the patient cohort. Statistical analyses were performed using analysis of variance. RESULTS The mean maximal doses for the GK-SRS and IMRT plans were 30 Gy and 29 Gy with margin prescription doses of 16 Gy and 24 Gy, respectively. The IORT dose was 30 Gy to the applicator surface. HIs varied based on calculation methods, but maintained consistency when comparing across platforms with IORT having the lower mean HI value (0.56; 95% confidence interval (CI) 0.55-0.60) in single-fraction treatment, compared with GK-SRS (0.77; 95% CI 0.76-0.80). The mean multisession IMRT HI was lower than both single-fraction treatment modalities at 0.41 (95% CI 0.40-0.42). CONCLUSIONS When using the HI as the primary dosimetric parameter for adjuvant radiation plans after surgical resection of brain metastases IORT offers improved dose homogeneity compared with GK-SRS in single-fraction treatment, whereas fractionated LINAC-based IMRT was superior with respect to the HI in comparison among all three methods.
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Affiliation(s)
- Basem A Dahshan
- Department of Radiation Oncology, West Virginia University, Morgantown, WV
| | - Joshua S Weir
- Department of Radiation Oncology, West Virginia University, Morgantown, WV
| | - Robert P Bice
- Department of Radiation Oncology, West Virginia University, Morgantown, WV
| | - Paul Renz
- Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, PA
| | | | - Linda Poplawski
- Department of Radiation Oncology, West Virginia University, Morgantown, WV
| | - Joshua Hack
- Department of Radiation Oncology, West Virginia University, Morgantown, WV
| | - John A Vargo
- Department of Radiation Oncology, UPMC, Pittsburgh, PA
| | - Christopher P Cifarelli
- Department of Radiation Oncology, West Virginia University, Morgantown, WV; Department of Neurosurgery, West Virginia University, Morgantown, WV.
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Patel G, Mandal A, Choudhary S, Mishra R, Shende R. Plan evaluation indices: A journey of evolution. Rep Pract Oncol Radiother 2020; 25:336-344. [PMID: 32210739 PMCID: PMC7082629 DOI: 10.1016/j.rpor.2020.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/07/2020] [Accepted: 03/02/2020] [Indexed: 12/27/2022] Open
Abstract
AIM A systemic review and analysis of evolution journey of indices, such as conformity index (CI), homogeneity index (HI) and gradient index (GI), described in the literature. BACKGROUND Modern radiotherapy techniques like VMAT, SRS and SBRT produce highly conformal plans and provide better critical structure and normal tissue sparing. These treatment techniques can generate a number of competitive plans for the same patients with different dose distributions. Therefore, indices like CI, HI and GI serve as complementary tools in addition to visual slice by slice isodose verification while plan evaluation. Reliability and accuracy of these indices have been tested in the past and found shortcomings and benefits when compared to one another. MATERIAL AND METHODS Potentially relevant studies published after 1993 were identified through a pubmed and web of science search using words "conformity index", "Homogeneity index", "Gradient index"," Stereotactic radiosurgery"," stereotactic Body radiotherapy" "complexity metrics" and "plan evaluation index". Combinations of words "plan evaluation index conformity index" were also searched as were bibliographies of downloaded papers. RESULTS AND CONCLUSIONS Mathematical definitions of plan evaluation indices modified with time. CI definitions presented by various authors tested at their own and could not be generalized. Those mathematical definitions of CI which take into account OAR sparing grant more confidence in plan evaluation. Gradient index emerged as a significant plan evaluation index in addition to CI whereas homogeneity index losing its credibility. Biological index base plan evaluation is becoming popular and may replace or alter the role of dosimetrical indices.
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Affiliation(s)
- Ganeshkumar Patel
- Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Abhijit Mandal
- Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Sunil Choudhary
- Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Ritusha Mishra
- Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Ravindra Shende
- Department of Radiotherapy, Balco Medical Center, New Raipur, Sector 36, Raipur, Chattisgarh 493661, India
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Borghetti P, Pedretti S, Spiazzi L, Avitabile R, Urpis M, Foscarini F, Tesini G, Trevisan F, Ghirardelli P, Pandini SA, Triggiani L, Magrini SM, Buglione M. Whole brain radiotherapy with adjuvant or concomitant boost in brain metastasis: dosimetric comparison between helical and volumetric IMRT technique. Radiat Oncol 2016; 11:59. [PMID: 27094398 PMCID: PMC4837558 DOI: 10.1186/s13014-016-0634-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 04/12/2016] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND To compare and evaluate the possible advantages related to the use of VMAT and helical IMRT and two different modalities of boost delivering, adjuvant stereotactic boost (SRS) or simultaneous integrated boost (SIB), in the treatment of brain metastasis (BM) in RPA classes I-II patients. METHODS Ten patients were treated with helical IMRT, 5 of them with SRS after whole brain radiotherapy (WBRT) and 5 with SIB. MRI co-registration with planning CT was mandatory and prescribed doses were 30 Gy in 10 fractions (fr) for WBRT and 15Gy/1fr or 45Gy/10fr in SRS or SIB, respectively. For each patient, 4 "treatment plans" (VMAT SRS and SIB, helical IMRT SRS and SIB) were calculated and accepted if PTV boost was included in 95 % isodose and dose constraints of the main organs at risk were respected without major deviations. Homogeneity Index (HI), Conformal Index (CI) and Conformal Number (CN) were considered to compare the different plans. Moreover, time of treatment delivery was calculated and considered in the analysis. RESULTS Volume of brain metastasis ranged between 1.43 and 51.01 cc (mean 12.89 ± 6.37 ml) and 3 patients had double lesions. V95% resulted over 95 % in the average for each kind of technique, but the "target coverage" was inadequate for VMAT planning with two sites. The HI resulted close to the ideal value of zero in all cases; VMAT-SIB, VMAT-SRS, Helical IMRT-SIB and Helical IMRT-SRS showed mean CI of 2.15, 2.10, 2.44 and 1.66, respectively (optimal range: 1.5-2.0). Helical IMRT-SRS was related to the best and reliable finding of CN (0.66). The mean of treatment time was 210 s, 467 s, 440 s, 1598 s, respectively, for VMAT-SIB, VMAT-SRS, Helical IMRT-SIB and Helical IMRT-SRS. CONCLUSIONS This dosimetric comparison show that helical IMRT obtain better target coverage and respect of CI and CN; VMAT could be acceptable in solitary metastasis. SIB modality can be considered as a good choice for clinical and logistic compliance; literature's preliminary data are confirming also a radiobiological benefit for SIB. Helical IMRT-SRS seems less effective for the long time of treatment compared to other techniques.
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Affiliation(s)
- Paolo Borghetti
- Radiation Oncology Department, University and Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy.
| | - Sara Pedretti
- Radiation Oncology Department, University and Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
| | - Luigi Spiazzi
- Medical Physics Department, Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
| | - Rossella Avitabile
- Medical Physics Department, Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
| | - Mauro Urpis
- Radiation Oncology Department, University and Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
| | - Federica Foscarini
- Radiation Oncology Department, University and Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
| | - Giulia Tesini
- Medical Physics Department, Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
| | - Francesca Trevisan
- Radiation Oncology Department, University and Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
| | - Paolo Ghirardelli
- Radiation Oncology Department, University and Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
| | - Sara Angela Pandini
- Radiation Oncology Department, University and Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
| | - Luca Triggiani
- Radiation Oncology Department, University and Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
| | - Stefano Maria Magrini
- Radiation Oncology Department, University and Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
| | - Michela Buglione
- Radiation Oncology Department, University and Spedali Civili Brescia, P.le Spedali Civili 1, Brescia, Italy
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Rosas JG, Armenta S, Cruz J, Blanco M. A new approach to determine the homogeneity in hyperspectral imaging considering the particle size. Anal Chim Acta 2013; 787:173-80. [PMID: 23830436 DOI: 10.1016/j.aca.2013.05.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 05/16/2013] [Accepted: 05/23/2013] [Indexed: 11/30/2022]
Abstract
Determining homogeneity of a mixture using hyperspectral-imaging (HSI) techniques is at this moment an interesting research subject in pharmaceutical industry. A new methodology based in the macropixel analysis technique for the homogeneity assessment in powder blend mixtures has been developed. The appropriate selection of the macropixel size for evaluation of the homogeneity is a topic under discussion. We propose that the macropixel size selection would be based in a statistical criterion called "representative sample size" criterion. Moreover, it has been demonstrated that the macropixel size should be a function of the particle size and, thus, the particle size has been included in the formula to calculate the macropixel size. The proposed equations allow to accurately calculate the homogeneity index (H% Poole). By means of using simulated chemical images, a relationship between the H% Poole index and the controlled homogeneity was established. The method has been applied to determine the homogeneity of binary and ternary powder blends mixtures of different pharmaceuticals discriminating between homogeneous and non-homogeneous samples.
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Affiliation(s)
- J G Rosas
- Department of Chemistry, Faculty of Sciences, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain
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Iqbal K, Isa M, Buzdar SA, Gifford KA, Afzal M. Treatment planning evaluation of sliding window and multiple static segments technique in intensity modulated radiotherapy. Rep Pract Oncol Radiother 2012; 18:101-6. [PMID: 24416536 DOI: 10.1016/j.rpor.2012.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 08/12/2012] [Accepted: 10/19/2012] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND The demand of improved dose conformity of the tumor has been increased in radiation therapy with the advent of recent imaging facilities and efficient computer technologies. AIM We compared the intensity modulated radiotherapy (IMRT) plans delivered with the sliding window (SW IMRT) and step and shoot (SS IMRT) techniques. MATERIALS AND METHODS Thirteen patients were planned on 15 MV X-ray for five, seven, nine and thirteen beams direction making the dose constraints analogous. Eclipse treatment planning system with Helios inverse planning software, and Linear Accelerator Varian 2100 C/D with 120 multileaf collimators (MLCs) were used. Gamma analysis was applied to the data acquired with the MapCheck 2™ for different beam directions plan in the sliding window and step and shoot technique to meet the 95% pass criteria at 3%/3 mm. The plans were scrutinized using D mean, D max, D1%, D95%, dose uniformity index (UI), dose conformity index (CI), dose homogeneity index (HI) and monitor units (MUs). RESULTS Our data show comparable coverage of the planning target volume (PTV) for both the sliding window and step and shoot techniques. The volume of PTV receiving the prescription dose was 99.8 ± 0.05% and the volume of PTV receiving the maximum dose was 107.6 ± 2.5% in both techniques. Bladder and rectum maximum mean doses for the sliding window and step and shoot plans were 38.1 ± 2.6% and 42.9 ± 10.7%. Homogeneity index (HI) for both techniques was 0.12 ± 0.02 and 0.13 ± 0.02, uniformity index (UI) was 1.07 ± 0.02 and 108 ± 0.01 and conformity index at 98% isodose (CI 98%) was 0.96 ± 0.005 and 0.96 ± 0.005 for the sliding window and step and shoot techniques, respectively, and MUs were 10 ± 12% lower in the step and shoot compared to the sliding window technique. CONCLUSION All these factors indicate that coverage for PTV was nearly identical but dose to organs-at-risk (OARs) was lower in the step and shoot technique.
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Affiliation(s)
- Khalid Iqbal
- Department of Physics, The Islamia University of Bahawalpur, Bahawalpur, Pakistan ; Department of Radiation Oncology, Shaukat Khanum Cancer Hospital and Research Center, Lahore, Pakistan ; Department of Radiation Physics, MD Anderson Cancer Center, University of Texas, USA
| | - Muhammad Isa
- Department of Physics, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
| | - Saeed Ahmad Buzdar
- Department of Physics, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
| | - Kent Aallen Gifford
- Department of Radiation Physics, MD Anderson Cancer Center, University of Texas, USA
| | - Muhammad Afzal
- Department of Physics, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
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