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Fuse H, Otsuki S, Fujisaki T, Yasue K, Hanada K, Tomita F, Abe S. Verification of morphological and physical properties for the development of a lung substitute phantom using microspheres. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:064101. [PMID: 35778036 DOI: 10.1063/5.0090471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/07/2022] [Indexed: 06/15/2023]
Abstract
This paper proposes a new concept of phantom development, along with the utilization of new materials that can reproduce lung morphology and density. A lung substitute phantom using microspheres was fabricated; then, its dosimetric utility in radiotherapy was investigated, during which the density was adjusted to closely resemble the morphology of the actual human lung. Microspheres were used to reproduce alveoli, which are the main components of the lung. By changing the ratio of urethane, which is commonly used in soft tissue phantoms, to microspheres, we reproduced the density change of the lungs due to respiration. Here, we fabricated two slab-like lung substitutes to emulate commercially used phantoms. Although there is room for improvement in terms of practicality, the substitutes were easy to fabricate. Microscopic observation of the cut surface of the phantoms showed that the morphology of the phantoms mimicked the alveoli more faithfully than commercial phantoms. Furthermore, to compensate for the energy-independent mass attenuation and mass collision inhibition ability required by the tissue substitute phantom, we examined the physical properties of the phantom and confirmed that there was negligible energy dependence.
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Affiliation(s)
- Hiraku Fuse
- Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2, Ami-machi, Inashiki-gun, Ibaraki 300-3094, Japan
| | - Shohei Otsuki
- Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2, Ami-machi, Inashiki-gun, Ibaraki 300-3094, Japan
| | - Tatsuya Fujisaki
- Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2, Ami-machi, Inashiki-gun, Ibaraki 300-3094, Japan
| | - Kenji Yasue
- Graduate School of Health Sciences, Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2, Ami-machi, Inashiki-gun, Ibaraki 300-3094, Japan
| | - Koichi Hanada
- Graduate School of Health Sciences, Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2, Ami-machi, Inashiki-gun, Ibaraki 300-3094, Japan
| | - Fumihiro Tomita
- Graduate School of Health Sciences, Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2, Ami-machi, Inashiki-gun, Ibaraki 300-3094, Japan
| | - Shinji Abe
- Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2, Ami-machi, Inashiki-gun, Ibaraki 300-3094, Japan
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Tan HQ, Koh CWY, Tan LKR, Lew KS, Chua CGA, Ang KW, Lee JCL, Park SY. A transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3D printed tumor phantom. J Appl Clin Med Phys 2022; 23:e13560. [PMID: 35147283 PMCID: PMC9121038 DOI: 10.1002/acm2.13560] [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: 07/27/2021] [Revised: 12/27/2021] [Accepted: 01/29/2022] [Indexed: 11/21/2022] Open
Abstract
Backgrounds Respiratory gating is one of the motion management techniques that is used to deliver radiation dose to a tumor at a specific position under free breathing. However, due to the dynamic feedback process of this approach, regular equipment quality assurance (QA) and patient‐specific QA checks need to be performed. This work proposes a new QA methodology using electronic portal imaging detector (EPID) to determine the target localization accuracy of phase gating. Methods QA tools comprising 3D printed spherical tumor phantoms, programmable stages, and an EPID detector are characterized and assembled. Algorithms for predicting portal dose (PD) through moving phantoms are developed and verified using gamma analysis for two spherical tumor phantoms (2 cm and 4 cm), two different 6 MV volumetric modulated arc therapy plans, and two different gating windows (30%–70% and 40%–60%). Comparison between the two gating windows is then performed using the Wilcoxon signed‐rank test. An optimizer routine, which is used to determine the optimal window, based on maximal gamma passing rate (GPR), was applied to an actual breathing curve and breathing plan. This was done to ascertain if our method yielded a similar result with the actual gating window. Results High GPRs of more than 97% and 91% were observed when comparing the predicted PD with the measured PD in moving phantom at 2 mm/2% and 1 mm/1% levels, respectively. Analysis of gamma heatmaps shows an excellent agreement with the tumor phantom. The GPR of 40%–60% PD was significantly lower than that of the 30%–70% PD at the 1 mm/1% level (p = 0.0064). At the 2 mm/2% level, no significant differences were observed. The optimizer routine could accurately predict the center of the gating window to within a 10% range. Conclusion We have successfully performed and verified a new method for QA with the use of a moving phantom with EPID for phase gating with real‐time position management.
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Affiliation(s)
- Hong Qi Tan
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore
| | - Calvin Wei Yang Koh
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore
| | - Lloyd Kuan Rui Tan
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore
| | - Kah Seng Lew
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore
| | | | - Khong Wei Ang
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore
| | - James Cheow Lei Lee
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore.,Division of Physics and Applied Physics, Nanyang Technological University, Singapore, Singapore
| | - Sung Yong Park
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore.,Oncology Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore
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Thomas DH, Tan J, Neylon J, Dou T, O’Connell D, McNitt-Gray M, Lee P, Lamb J, Low DA. Investigating the minimum scan parameters required to generate free-breathing motion artefact-free fast-helical CT. Br J Radiol 2017; 91:20170597. [DOI: 10.1259/bjr.20170597] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- David H Thomas
- Department of Radiation Oncology, University of Colorado School of Medicine,University of Colorado School of Medicine, Aurora, CO, USA
| | - Jun Tan
- Department of Radiation Oncology, University of Texas Southwestern Medical Center,University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jack Neylon
- Department of Radiation Oncology, University of California, Los Angeles,University of California, Los Angeles, California, CA, USA
| | - Tai Dou
- Department of Radiation Oncology, University of California, Los Angeles,University of California, Los Angeles, California, CA, USA
| | - Dylan O’Connell
- Department of Radiation Oncology, University of California, Los Angeles,University of California, Los Angeles, California, CA, USA
| | - Michael McNitt-Gray
- Department of Radiological Sciences, University of California,University of California, California, CA, USA
| | - Percy Lee
- Department of Radiation Oncology, University of California, Los Angeles,University of California, Los Angeles, California, CA, USA
| | - James Lamb
- Department of Radiation Oncology, University of California, Los Angeles,University of California, Los Angeles, California, CA, USA
| | - Daniel A Low
- Department of Radiation Oncology, University of California, Los Angeles,University of California, Los Angeles, California, CA, USA
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Chang Z, Cai J, Wang Z, Yin FF. Evaluation of motion measurement using cine MRI for image guided stereotactic body radiotherapy on a new phantom platform. JOURNAL OF RADIOSURGERY AND SBRT 2011; 1:109-115. [PMID: 29296304 PMCID: PMC5675467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 09/06/2011] [Indexed: 06/07/2023]
Abstract
The objective of this study is to investigate accuracy of motion tracking of cine magnetic resonance imaging (MRI) for image-guided stereotactic body radiotherapy. A phantom platform was developed in this work to fulfill the goal. The motion phantom consisted of a platform, a solid thread, a motor and a control system that can simulate motion in various modes. To validate its reproducibility, the phantom platform was setup three times and imaged with fluoroscopy using an electronic portal imaging device (EPID) for the same motion profile. After the validation test, the phantom platform was evaluated using cine MRI at 2.5 frames/second on a 1.5T GE scanner using five different artificial profiles and five patient profiles. The above profiles were again measured with EPID fluoroscopy and used as references. Discrepancies between measured profiles from cine MRI and EPID were quantified using root-mean-square (RMS) and standard deviation (SD). Pearson's product moment correlational analysis was used to test correlation. The standard deviation for the reproducibility test was 0.28 mm. The discrepancies (RMS) between all profiles measured by cine MRI and EPID fluoroscopy ranged from 0.30 to 0.49 mm for artificial profiles and ranged from 0.75 to 0.91 mm for five patient profiles. The cine MRI sequence could precisely track phantom motion and the proposed motion phantom was feasible to evaluate cine MRI accuracy.
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Affiliation(s)
- Zheng Chang
- Department of Radiation Oncology, Duke University, Durham, North Carolina, USA
| | - Jing Cai
- Department of Radiation Oncology, Duke University, Durham, North Carolina, USA
| | - Ziheng Wang
- Department of Radiation Oncology, Duke University, Durham, North Carolina, USA
| | - Fang-Fang Yin
- Department of Radiation Oncology, Duke University, Durham, North Carolina, USA
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Chinneck CD, McJury M, Hounsell AR. The potential for undertaking slow CT using a modern CT scanner. Br J Radiol 2010; 83:687-93. [PMID: 20551253 DOI: 10.1259/bjr/31551018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Respiratory motion complicates target volume definition for patients with lung cancer. The use of slow CT to aid in the definition of moving target volumes was investigated. Standard and slow scans of an oscillating phantom were acquired using gantry rotation periods of 0.8 and 1.5 s and pitches of 0.95 and 0.50, respectively. The resultant images of three spheres within the phantom, labelled as A, B and C with diameters of 3.7, 2.8 and 2.2 cm, were analysed. The central co-ordinates of each volume were determined, and the ratio of the target volume outlined on CT (TV(CT)) to the true target volume (TV) was calculated. For 1.5 cm peak-to-trough (PTT) motion, standard CT mean ratios of 0.8, 0.8 and 0.7 were obtained for spheres A, B and C, respectively, whereas slow CT resulted in a mean ratio of 0.9 for all three spheres. For 2.5 cm motion, standard CT mean ratios of 0.8, 0.7 and 0.7 were obtained, whereas the slow CT mean ratios were 0.9, 0.9 and 0.8. The deviation of the central co-ordinate for the slow CT volumes was within 0.1 cm whereas deviations of up to 0.7 cm were seen using standard CT. This study indicates the potential benefit of using slow CT, even on modern scanners capable of rotation periods only down to 1.5 s, to define moving target volumes more accurately and reproducibly moving target volumes, and aid in the management of respiratory motion for patients with lung cancer.
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Affiliation(s)
- C D Chinneck
- Northern Ireland Cancer Centre, Belfast City Hospital, Belfast Health and Social Care Trust, Lisburn Road, Belfast, UK.
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Szegedi M, Rassiah-Szegedi P, Fullerton G, Wang B, Salter B. A proto-type design of a real-tissue phantom for the validation of deformation algorithms and 4D dose calculations. Phys Med Biol 2010; 55:3685-99. [PMID: 20530851 DOI: 10.1088/0031-9155/55/13/008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The purpose of this study is to design a real-tissue phantom for use in the validation of deformation algorithms. A phantom motion controller that runs sinusoidal and non-regular patient-based breathing pattern, via a piston, was applied to porcine liver tissue. It was regulated to simulate movement ranges similar to recorded implanted liver markers from patients. 4D CT was applied to analyze deformation. The suitability of various markers in the liver and the position reproducibility of markers and of reference points were studied. The similarity of marker motion pattern in the liver phantom and in real patients was evaluated. The viability of the phantom over time and its use with electro-magnetic tracking devices were also assessed. High contrast markers, such as carbon markers, implanted in the porcine liver produced less image artifacts on CT and were well visualized compared to metallic ones. The repositionability of markers was within a measurement accuracy of +/-2 mm. Similar anatomical patient motions were reproducible up to elongations of 3 cm for a time period of at least 90 min. The phantom is compatible with electro-magnetic tracking devices and 4D CT. The phantom motion is reproducible and simulates realistic patient motion and deformation. The ability to carry out voxel-based tracking allows for the evaluation of deformation algorithms in a controlled environment with recorded patient traces. The phantom is compatible with all therapy devices clinically encountered in our department.
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Affiliation(s)
- M Szegedi
- Health Science Center, University of Texas, San Antonio, TX, USA.
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Tai A, Christensen JD, Gore E, Khamene A, Boettger T, Li XA. Gated Treatment Delivery Verification With On-Line Megavoltage Fluoroscopy. Int J Radiat Oncol Biol Phys 2010; 76:1592-8. [DOI: 10.1016/j.ijrobp.2009.08.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 08/04/2009] [Accepted: 08/04/2009] [Indexed: 12/25/2022]
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Padmanaban S, Boopathy R, Kunjithapatham B, Sukumar P, Nagarajan V. A phantom study on the effects of target motion in non-gated kV-CBCT imaging. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2010; 33:59-64. [PMID: 20333565 DOI: 10.1007/s13246-010-0010-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 02/20/2010] [Indexed: 12/25/2022]
Abstract
Kilo-voltage cone beam computed tomography (kV-CBCT) integrated with a linac can produce online volumetric and anatomical images for patient set-up and dosimetric analysis in adaptive radiotherapy. However CBCT is prone to motion artifacts. This study investigates the impact of target motion in CBCT imaging. To simulate respiratory movement, a dynamic phantom was moved in three-dimensions with a period of 4 s and two different amplitudes (PA1 and PA2). The targets of well defined geometries were made using wax. A reference image of the static target was achieved with fan beam CT. Using CBCT, the targets in static and dynamic modes were imaged under full-fan beam conditions. The length of average HU spread was reduced in range from 19.35 to 44.44% along the cranio-caudal direction of targets. The percentage volume loss of dynamic targets imaged using CBCT (for Hounsfield Units with window width -500 to 0) ranged from 14.35 to 30.95% for PA1 and 21.29 to 43.80% for PA2 in comparison with static targets imaged with fan beam CT. A significant loss of volumetric information may result for non-gated CBCT imaging of moving targets and may result in a systematic error in re-contouring when CBCT images are used for radiotherapy re-planning.
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Padmanaban S, Boopathy R, Kunjithapatham B, Sukumar P, Nagarajan V. The effects of target motion in kV-CBCT imaging. Pol J Radiol 2010; 75:61-6. [PMID: 22802763 PMCID: PMC3389851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 10/28/2009] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND To study the impact of target motion in kV-CBCT imaging. MATERIAL/METHODS To simulate the respiratory movement, dynamic phantom was programmed to move in three-dimension with a period of four seconds and of two different amplitudes (PA1 and PA2). The targets of well defined geometries (cylinder, sphere, solid triangle, U-shaped and dumbbell) were made using wax. The static targets were CT imaged (reference image). Using CBCT, the targets in static and dynamic modes were imaged under full-fan beam. The line profiles along cranio-caudal direction, influence of target's initial moving phase and volume estimation using auto-contouring tool were used to analyze the effects of target motion on CBCT imaging. RESULTS Comparing the line profiles of targets in CBCT with CT, the length of average HU spread was reduced by 42.54±1.85%, except the cylindrical target which is by 19.35% for PA1. The percentage difference in reconstructed volume of static targets imaged using CBCT and CT (HU WW -500 to 0) ranges from -1.32% to -5.94%. The volume losses for targets imaged in dynamic mode PA1 ranges from 14.35% to 30.95% and for PA2 it was 21.29% to 43.80%. The solid triangle and cylindrical targets suffered the maximum and minimum volume losses respectively. CONCLUSIONS Non-gated CBCT imaging of the moving targets encounters significant loss of volumetric information, due to scatter artifacts. These may result in a systematic error in re-contouring when CBCT images are used for the re-planning work.
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Affiliation(s)
- Sriram Padmanaban
- Author’s address: Sriram Padmanaban, Cancer Institution (WIA), Adyar Chennai Tamilnadu India, e-mail:
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