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Saini A, Verma T, Pandey VP, Singh A, Kumar P. Performance evaluation of Monaco radiotherapy treatment planning system using CIRS Thorax Phantom: Dosimetric assessment of flattened and non-flattened photon beams. J Cancer Res Ther 2023; 19:793-800. [PMID: 37470613 DOI: 10.4103/jcrt.jcrt_967_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
Abstract
Aim The present study was undertaken to evaluate the performance of different algorithms for flattening filter-free (FFF) and flattened (FF) photon beams in three different in-homogeneities. Materials and Method Computed tomography (CT) image sets of the CIRS phantom maintained in the SAD setup by placing the ionization chamber in the lung, bone, and tissue regions, respectively, were acquired. The treatment planning system (TPS) calculated and the ionization chamber measured the doses at the center of the chamber (in the three mediums) were recorded for the flattened and non-flattened photon beams. Results The results were reported for photon energies of 6 MV, 10 MV, 15 MV, 6 FFF, and 10 FFF of field sizes 5 × 5 cm2, 10 × 10 cm2, and 15 × 15 cm2. In the bone inhomogeneity, the pencil beam algorithm predicted that the maximum dose variation was 4.88% of measured chamber dose in 10-MV photon energy for the field size 10 × 10 cm2. In water inhomogeneity, both the collapsed cone and Monte Carlo algorithm predicted that the maximum dose variation was ± 3% of measured chamber dose in 10-MV photon energy for the field size 10 × 10 cm2 and in 10-MV FFF photon energy for the field size 5 × 5 cm2, whereas in lung inhomogeneity, the pencil beam algorithm predicted that the highest dose variation was - 6.9% of measured chamber dose in 10-MV FFF photon energy for the field size 5 × 5 cm2. Conclusion FF and FFF beams performed differently in lung, water, and bone mediums. The assessment of algorithms was conducted using the anthropomorphic phantom; therefore, these findings may help in the selection of appropriate algorithms for particular clinical settings in radiation delivery.
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Affiliation(s)
- Amit Saini
- Department of Medical Physics, Tata Memorial Center, Homi Bhabha Cancer Hospital, Sangrur, Punjab; Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India
| | - Teerthraj Verma
- Department of Radiotherapy, King George Medical University, Lucknow, Uttar Pradesh, India
| | - V P Pandey
- Department of Medical Physics, Hind Institute of Medical Sciences, Safedabad, Barabanki, Uttar Pradesh, India
| | - Avtar Singh
- Department of Medical Physics, Tata Memorial Center, Homi Bhabha Cancer Hospital, Sangrur, Punjab; Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India
| | - Pankaj Kumar
- Chitkara University Institute of Engineering and Technology; Centre for Liquid Crystal Research, Chitkara University Research and Innovation Network, Chitkara University, Punjab, India
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Saini A, Pandey VP, Kumar P, Singh A, Pasricha R. Investigation of tube voltage dependence on CT number and its effect on dose calculation algorithms using thorax phantom in Monaco treatment planning system for external beam radiation therapy. J Med Phys 2021; 46:315-323. [PMID: 35261502 PMCID: PMC8853450 DOI: 10.4103/jmp.jmp_124_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 08/29/2021] [Accepted: 08/29/2021] [Indexed: 11/10/2022] Open
Abstract
Introduction The accuracy of dose calculation algorithms depends on the electron density and computed tomography (CT) number of medium scanned. Our study aimed to verify the impact of different CT scanning protocols on Hounsfield unit (HU) and effect on dose calculation algorithms. Materials and Methods CIRS thorax phantom with different density material plugs was scanned at varying tube voltages from CT scanner and HU values were measured in treatment planning system (TPS). Calibration curves of electron density at different tube voltages were plotted and used for dose calculation with different calculation algorithms at varying high energy megavoltage photon energies. Results Insignificant difference is obtained in electron density curves plotted at different tube voltages. The mean variation in HU values was found at different tube voltages for bone, lung, and water are 896.75 (standard deviation [SD] 122.88), -799.25 (SD 5.74), and -17.5 (SD 0.57), respectively. The estimated P values for change in HU values were 0.089, 0.258, and 0.121 for bone, lung, and water, respectively. Pencil beam (PB) convolution and collapsed cone algorithms show no significant dose difference, i.e., <1% variation and Monte Carlo (MC) shows maximum dose difference up to 1.4%. Conclusion Third-generation algorithms such as MC shows dependence on varying tube voltages in dose calculation. Calibration curves plotted at different kVp in TPS advised to be chosen wisely to avoid any dosimetric errors in different medium.
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Affiliation(s)
- Amit Saini
- Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India,Department of Medical Physics, Tata Memorial Center, Homi Bhabha Cancer Hospital, Sangrur, Punjab, India
| | - V P Pandey
- Department of Medical Physics, Hind Institute of Medical Sciences, Safedabad, Barabanki, Uttar Pradesh, India,Address for correspondence: Dr. V. P. Pandey, Department of Medical Physics, Hind Institute of Medical Sciences, Safedabad, Barabanki, U.P, India E-mail: aryanbarc@gmailcom
Dr. Pankaj Kumar Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India Centre for Liquid Crystal Research, Chitkara University Research and Innovation Network, Chitkara University, Punjab, India E-mail:
| | - Pankaj Kumar
- Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India,Centre for Liquid Crystal Research, Chitkara University Research and Innovation Network, Chitkara University, Punjab, India,Address for correspondence: Dr. V. P. Pandey, Department of Medical Physics, Hind Institute of Medical Sciences, Safedabad, Barabanki, U.P, India E-mail: aryanbarc@gmailcom
Dr. Pankaj Kumar Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India Centre for Liquid Crystal Research, Chitkara University Research and Innovation Network, Chitkara University, Punjab, India E-mail:
| | - Avtar Singh
- Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India,Department of Medical Physics, Tata Memorial Center, Homi Bhabha Cancer Hospital, Sangrur, Punjab, India
| | - Rajesh Pasricha
- Department of Radiotherapy, All India Institute of Medical Sciences, Bhopal, Madhya Pradesh, India
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