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Erickson BG, Cui Y, Ackerson BG, Kelsey CR, Yin FF, Niedzwiecki D, Adamson J. Uncertainties in the dosimetric heterogeneity correction and its potential effect on local control in lung SBRT. Biomed Phys Eng Express 2023; 9. [PMID: 36827685 DOI: 10.1088/2057-1976/acbeae] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 02/24/2023] [Indexed: 02/26/2023]
Abstract
Objective. Dose calculation in lung stereotactic body radiation therapy (SBRT) is challenging due to the low density of the lungs and small volumes. Here we assess uncertainties associated with tissue heterogeneities using different dose calculation algorithms and quantify potential associations with local failure for lung SBRT.Approach. 164 lung SBRT plans were used. The original plans were prepared using Pencil Beam Convolution (PBC, n = 8) or Anisotropic Analytical Algorithm (AAA, n = 156). Each plan was recalculated with AcurosXB (AXB) leaving all plan parameters unchanged. A subset (n = 89) was calculated with Monte Carlo to verify accuracy. Differences were calculated for the planning target volume (PTV) and internal target volume (ITV) Dmean[Gy], D99%[Gy], D95%[Gy], D1%[Gy], and V100%[%]. Dose metrics were converted to biologically effective doses (BED) usingα/β= 10Gy. Regression analysis was performed for AAA plans investigating the effects of various parameters on the extent of the dosimetric differences. Associations between the magnitude of the differences for all plans and outcome were investigated using sub-distribution hazards analysis.Main results. For AAA cases, higher energies increased the magnitude of the difference (ΔDmean of -3.6%, -5.9%, and -9.1% for 6X, 10X, and 15X, respectively), as did lung volume (ΔD99% of -1.6% per 500cc). Regarding outcome, significant hazard ratios (HR) were observed for the change in the PTV and ITV D1% BEDs upon univariate analysis (p = 0.042, 0.023, respectively). When adjusting for PTV volume and prescription, the HRs for the change in the ITV D1% BED remained significant (p = 0.039, 0.037, respectively).Significance. Large differences in dosimetric indices for lung SBRT can occur when transitioning to advanced algorithms. The majority of the differences were not associated with local failure, although differences in PTV and ITV D1% BEDs were associated upon univariate analysis. This shows uncertainty in near maximal tumor dose to potentially be predictive of treatment outcome.
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Affiliation(s)
- Brett G Erickson
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, United States of America
| | - Yunfeng Cui
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, United States of America
| | - Bradley G Ackerson
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, United States of America
| | - Christopher R Kelsey
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, United States of America
| | - Fang-Fang Yin
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, United States of America
| | - Donna Niedzwiecki
- Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC, United States of America
| | - Justus Adamson
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, United States of America
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Erickson BG, Ackerson BG, Kelsey CR, Yin FF, Adamson J, Cui Y. The effect of various dose normalization strategies when implementing linear Boltzmann transport equation dose calculation for lung SBRT planning. Pract Radiat Oncol 2022; 12:446-456. [DOI: 10.1016/j.prro.2022.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 01/19/2022] [Accepted: 02/07/2022] [Indexed: 11/16/2022]
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Tuğrul T. The Effect of Algorithms on Dose Distribution in Inhomogeneous Phantom: Monaco Treatment Planning System versus Monte Carlo Simulation. J Med Phys 2021; 46:111-115. [PMID: 34566291 PMCID: PMC8415246 DOI: 10.4103/jmp.jmp_21_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/05/2021] [Accepted: 05/05/2021] [Indexed: 11/26/2022] Open
Abstract
Background: The aim of this study is to evaluate the dose calculation algorithms commonly used in TPS by using MC simulation in the highly different inhomogeneous region and in the small fields and to provide the following uniquely new information in the study of correction algorithm. Materials and Methods: We compared the dose distribution obtained by Monaco TPS for small fields. Results: When we examine lung medium, for four different fields, we can see that the algorithms begin to differ. In both the lung and bone environment, the percentage differences decrease as the field size increases. In areas less than or equal to 3x3 cm2, there are serious differences between the algorithms. The CC algorithm calculates a low dose value as the photon passes from the lung environment to water environment. We can also see that this algorithm measures a low dose value in voxel as the photon passes from the water medium to the bone medium. In the transition from the water environment to the bone environment or from the bone environment to the water environment, the results of the CC algorithm are not close to MC simulation. Conclusion: The effect of the algorithms used in TPS on dose distribution is very strong, especially in environment with high electron density variation and in applications such as Stereotactic Body Radiotherapy and Intensity Modulated Radiotherapy where small fields are used.
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Affiliation(s)
- Taylan Tuğrul
- Department of Radiation Oncology, Faculty of Medicine, Van Yüzüncü Yıl University, Van, Turkey
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Zaghian R, Sedighi Pashaki A, Haghparast A, Gholami MH, Mohammadi M. Investigation of Collapsed-cone Algorithm Accuracy in Small Fields and Heterogeneous Environments. J Biomed Phys Eng 2021; 11:143-150. [PMID: 33937122 PMCID: PMC8064127 DOI: 10.31661/jbpe.v0i0.1121] [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: 01/22/2019] [Accepted: 02/16/2019] [Indexed: 11/16/2022]
Abstract
Background: The use of small fields has increased by the emergence of advanced radiotherapy. Dose calculations of these fields are complex and challenging for many reasons such as lack of electrical equilibrium even in homogeneous environments, and this complexity will increase in presence of heterogeneity. According to the importance of delivery the accurate prescription dose to the target volume in the patient’s body, the dose calculation accuracy of used commercial algorithms in clinical treatment planning systems (TPS) should be evaluated. Objective: The present study aims to evaluate the accuracy of Collapsed-cone dose measurement algorithm in Isogray treatment planning system. Material and Methods: In this analytical study, the measurements were made in tissue equivalent solid water phantom with lung and bone heterogeneities by Pinpoint dosimeter (0.015 cm3 sensitive volume) in several radiation fields (1×1 to 5×5 cm2). The phantoms were irradiated with 6, 10 and 18 MV photon beams and finally, the results of experimental calculations were compared with treatment planning outputs. Results: In all setups, the maximum deviation occurred in the field of 1×1 cm2. Then, the maximum deviation was observed for 2×2 cm2 field size; however, it was up to 5% for homogeneous water phantom and lung heterogeneity. In 3×3 cm2 and larger fields, there was a good agreement between the results of the TPS and experimental dosimetry. The maximum deviation was observed in water-bone heterogeneity. Conclusion: This algorithm was able to pass the standard audit criteria, but it is better to be used more cautiously in bone heterogeneity, especially in low energies.
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Affiliation(s)
- Razieh Zaghian
- MSc, Medical Physics Department, Students Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Abdolazim Sedighi Pashaki
- MD, Radiation oncologist, Faculty of Medicine, Hamedan University of Medical Sciences, Hamedan, Iran
| | - Abbas Haghparast
- PhD, Department of Medical Physics, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mohammad Hadi Gholami
- PhD, Medical Physicist of Radiotherapy, Mahdieh Radiotherapy and Brachytherapy Charity Center, Hamedan, Iran
| | - Mahdi Mohammadi
- MSc, Medical Physics Department, Students Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
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Clemente S, Falco MD, Cagni E, Talamonti C, Boccia M, Gino E, Lorenzini E, Rosica F, Russo S, Alparone A, Zefiro D, Fiandra C. The influence of small field output factors simulated uncertainties on the calculated dose in VMAT plans for brain metastases: a multicentre study. Br J Radiol 2021; 94:20201354. [PMID: 33481637 DOI: 10.1259/bjr.20201354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES This multicentric study was carried out to investigate the impact of small field output factors (OFs) inaccuracies on the calculated dose in volumetric arctherapy (VMAT) radiosurgery brain plans. METHODS Nine centres, realised the same five VMAT plans with common planning rules and their specific clinical equipment Linac/treatment planning system commissioned with their OFs measured values (OFbaseline). In order to simulate OFs errors, two new OFs sets were generated for each centre by changing only the OFs values of the smallest field sizes (from 3.2 × 3.2 cm2 to 1 × 1 cm2) with well-defined amounts (positive and negative). Consequently, two virtual machines for each centre were recommissioned using the new OFs and the percentage dose differences ΔD (%) between the baseline plans and the same plans recalculated using the incremented (OFup) and decremented (OFdown) values were evaluated. The ΔD (%) were analysed in terms of planning target volume (PTV) coverage and organs at risk (OARs) sparing at selected dose/volume points. RESULTS The plans recalculated with OFdown sets resulted in higher variation of doses than baseline within 1.6 and 3.4% to PTVs and OARs respectively; while the plans with OFup sets resulted in lower variation within 1.3% to both PTVs and OARs. Our analysis highlights that OFs variations affect calculated dose depending on the algorithm and on the delivery mode (field jaw/MLC-defined). The Monte Carlo (MC) algorithm resulted significantly more sensitive to OFs variations than all of the other algorithms. CONCLUSION The aim of our study was to evaluate how small fields OFs inaccuracies can affect the dose calculation in VMAT brain radiosurgery treatments plans. It was observed that simulated OFs errors, return dosimetric calculation accuracies within the 3% between concurrent plans analysed in terms of percentage dose differences at selected dose/volume points of the PTV coverage and OARs sparing. ADVANCES IN KNOWLEDGE First multicentre study involving different Planning/Linacs about undetectable errors in commissioning output factor for small fields.
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Affiliation(s)
- Stefania Clemente
- Unit of Medical Physics and Radioprotection, Federico II University Hospital, Napoli, Italy
| | - Maria Daniela Falco
- Department of Radiation Oncology, "G. D'Annunzio" University, "SS. Annunziata" Hospital, Chieti, Italy
| | - Elisabetta Cagni
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Cinzia Talamonti
- Medical Physics Unit, University Of Florence, Azienda Ospedaliero Universitaria Careggi, Florence, Italy
| | | | - Eva Gino
- Medical PhysicDepartment, A.O. Ordine Mauriziano, Turin, Italy
| | - Elena Lorenzini
- U.O.C Fisica Sanitaria Area Nord, Azienda USL Nord Ovest Toscana, Massa Carrara, Italy
| | | | | | | | - Daniele Zefiro
- MedicaPhysics Unit, ASL5 Sistema Sanitario Regione Liguria, La Spezia, Italy
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Fogliata A, Esposito E, Paganini L, Reggiori G, Tomatis S, Scorsetti M, Cozzi L. The impact of scanning data measurements on the Acuros dose calculation algorithm configuration. Radiat Oncol 2020; 15:169. [PMID: 32650815 PMCID: PMC7350585 DOI: 10.1186/s13014-020-01610-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/02/2020] [Indexed: 11/24/2022] Open
Abstract
Background Many dose calculation algorithms for radiotherapy planning need to be configured for each clinical beam using pre-defined measurements. An optimization process adjusts the physical parameters able to estimate the energy released in the medium in any geometrical condition. This work investigates the impact of measured input data quality on the configuration of the type “c” Acuros-XB dose calculation algorithm in the Eclipse (Varian Medical Systems) treatment planning system. Methods Different datasets were acquired with the BeamScan water phantom (PTW) to configure 6 MV beams, for both flattened (6X) and flattening filter free mode (6FFF) for a Varian TrueBeam: (i) a correct dataset measured using a Semiflex-3D ion chamber, (ii) a set in missing lateral scatter conditions (MLS), (iii) a set with incorrect effective point of measurement (EPoM), (iv) sets acquired with PinPoint-3D chamber, DiodeP, microDiamond detectors. The Acuros-XB dose calculation algorithm (version 15.6) was configured using the reference dataset, the sets measured with the different detectors, with intentional errors, and using the representative beam data (RBD) made available by the vendor. The physical parameters obtained from each optimization process (spectrum, mean radial energy, electron contamination), were analyzed and compared. Calculated data were finally compared against the input and reference measurements. Results Concerning the physical parameters, the configurations presenting the largest differences were the MLS conditions (mean radial energy) and the incorrect EPoM (electron contamination). The calculation doses relative to the input data present low accuracy, with mean differences > 2% in some conditions. The PinPoint-3D ion chamber presented lower accuracy for the 6FFF beam. Regarding the RBD, calculations compared well with the input data used for the configuration, but not with the reference data. Conclusion The MLS conditions and the incorrect setting of the EPoM lead to erroneous configurations and should be avoided. The choice of an appropriate detector is important. Whenever the representative beam data is used, a careful check under more clinical geometrical conditions is advised.
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Affiliation(s)
- A Fogliata
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy.
| | - E Esposito
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy
| | - L Paganini
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy
| | - G Reggiori
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy
| | - S Tomatis
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy
| | - M Scorsetti
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy.,Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Milan-Pieve Emanuele, Italy
| | - L Cozzi
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Center - IRCCS, Via Manzoni 56, Milan-Rozzano, Italy.,Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Milan-Pieve Emanuele, Italy
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Liu T, Dai Z, Kang K, Gao L, Liu R, Ou‐Yang S. Comparative analysis of dose verification between computed tomography scan phantom and virtual digital phantom of Delta4. PRECISION RADIATION ONCOLOGY 2020. [DOI: 10.1002/pro6.1092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Ting‐Ting Liu
- Department of Radiation OncologyGansu Provincial Cancer Hospital Lanzhou China
| | - Zhi‐Tao Dai
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen HospitalChinese Academy of Medical Sciences and Peking Union Medical College Beijing China
| | - Kai‐Lian Kang
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen HospitalChinese Academy of Medical Sciences and Peking Union Medical College Beijing China
| | - Li‐Ying Gao
- Department of Radiation OncologyGansu Provincial Cancer Hospital Lanzhou China
| | - Rui‐Feng Liu
- Department of Radiation OncologyGansu Provincial Cancer Hospital Lanzhou China
| | - Shui‐Gen Ou‐Yang
- Department of Radiation OncologyGansu Provincial Cancer Hospital Lanzhou China
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Parwaie W, Refahi S, Ardekani MA, Farhood B. Different Dosimeters/Detectors Used in Small-Field Dosimetry: Pros and Cons. JOURNAL OF MEDICAL SIGNALS & SENSORS 2018; 8:195-203. [PMID: 30181968 PMCID: PMC6116321 DOI: 10.4103/jmss.jmss_3_18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
With the advent of complex and precise radiation therapy techniques, the use of relatively small fields is needed. Using such field sizes can cause uncertainty in dosimetry; therefore, special attention is required both in dose calculations and measurements. There are several challenges in small-field dosimetry such as the steep gradient of the radiation field, volume averaging effect, lack of charged particle equilibrium, partial occlusion of radiation source, beam alignment, and unable to use a reference dosimeter. Due to these challenges, special dosimeters are needed for small-field dosimetry, and this review article discusses this topic.
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Affiliation(s)
- Wrya Parwaie
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Soheila Refahi
- Department of Medical Physics, Faculty of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
| | - Mahdieh Afkhami Ardekani
- Department of Radiology, Faculty of Para-Medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Bagher Farhood
- Department of Radiology and Medical Physics, Faculty of Paramedical Sciences, Kashan University of Medical Sciences, Kashan, Iran
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Fogliata A, Cozzi L. Dose calculation algorithm accuracy for small fields in non-homogeneous media: The lung SBRT case. Phys Med 2017; 44:157-162. [DOI: 10.1016/j.ejmp.2016.11.104] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 11/02/2016] [Accepted: 11/10/2016] [Indexed: 11/28/2022] Open
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