Email this article 
Post a Comment 
Commissioning and quality control of a dedicated wide bore 3T MRI simulator for radiotherapy planning
Abstract
Purpose: The purpose of this paper is to describe a practical approach to commissioning and quality assurance (QA) of a dedicated wide-bore 3 Tesla (3T) magnetic resonance imaging (MRI) scanner for radiotherapy planning.
Methods: A comprehensive commissioning protocol focusing on radiotherapy (RT) specific requirements was developed and performed. RT specific tests included: uniformity characteristics of radio-frequency (RF) coil, couch top attenuation, geometric distortion, laser and couch movement and an end-to-end radiotherapy treatment planning test. General tests for overall system performance and safety measurements were also performed.
Results: The use of pre-scan based intensity correction increased the uniformity from 61.7% to 97% (body flexible coil), from 50% to 90% (large flexible coil) and from 51% to 98% (small flexible coil). RT flat top couch decreased signal-to-noise ratio (SNR) by an average of 42%. The mean and maximum geometric distortion was found to be 1.25 mm and 4.08 mm for three dimensional (3D) corrected image acquisition, 2.07 mm and 7.88 mm for two dimensional (2D) corrected image acquisition over 500 mm × 375 mm × 252 mm field of view (FOV). The accuracy of the laser and couch movement was less than ±1 mm. The standard deviation of registration parameters for the end-to-end test was less than 0.41 mm. An on-going QA program was developed to monitor the system’s performance.
Conclusion: A number of RT specific tests have been described for commissioning and subsequent performance monitoring of a dedicated MRI simulator (MRI-Sim). These tests have been important in establishing and maintaining its operation for RT planning.
Keywords
Full Text:
PDFReferences
Aird E, Conway J. CT simulation for radiotherapy treatment planning. Br J Radiol. 2002;75:937-49.
Devic S. MRI simulation for radiotherapy treatment planning. Med Phys. 2012; 39:6701-11.
Metcalfe P, Liney GP, Holloway L, et al. The potential for an enhanced role for MRI in radiation-therapy treatment planning. Technol Cancer Res Treat. 2013;12:429-46.
Fraass B, McShan DL, Diaz RF, et al. Integration of magnetic resonance imaging into radiation therapy treatment planning: I. Technical considerations. Int J Radiat Oncol Biol Phys. 1987;13:1897-908.
Liney GP, Owen SC, Beaumont AK, et al. Commissioning of a new wide-bore MRI scanner for radiotherapy planning of head and neck cancer. Br J Radiol. 2013;86:20130150.
Wang C, Chao M, Lee L, Xing L. MRI-based treatment planning with electron density information mapped from CT images: A preliminary study. Technol Cancer Res Treat. 2008;7:341-8.
Paulson ES, Erickson B, Schultz C, Li XA. Comprehensive MRI simulation methodology using a dedicated MRI scanner in radiation oncology for external beam radiation treatment planning. Med Phys. 2015;42:28-39.
Glide-Hurst CK, Wen N, Hearshen D, et al. Initial clinical experience with a radiation oncology dedicated open 1.0 T MR-simulation. J Appl Clin Med Phys. 2015;16:5201.
Mah D, Steckner M, Palacio E, et al. Characteristics and quality assurance of a dedicated open 0.23 T MRI for radiation therapy simulation. Med Phys. 2002;29:2541-7.
Liney GP, Moerland MA. Magnetic resonance imaging acquisition techniques for radiotherapy planning. Semin Radiat Oncol. 2014;24:160-8.
A Practical Guide to CT Simulation. Editors: Coia LR, Schultheiss TE, Hanks GE. Advanced Medical Publishing, 1995.
Ebert MA, Kenny J, Greer PB. Experience converting an RT department to full CT simulation: Technical issues identified during commissioning of a wide-bore scanner. J Med Imaging Radiat Oncol. 2009;53:325-30.
McGee K, Das IJ. Commissioning, acceptance testing and quality assurance of a CT simulator. In Coia LR, Schultheiss TE, Hanks GE. A Practical Guide to CT Simulation. 1995:5-23.
Zhang J, Sehgal V, Roa DE, et al. SU-GG-J-34: Comprehensive clinical commissioning and quality assurance procedures of a big bore CT simulator in a Radiation Oncology Department. Med Phys. 2010;37:3152-52.
Mutic S, Palta JR, Butker EK, et al. Quality assurance for computed-tomography simulators and the computed- tomography-simulation process: report of the AAPM Radiation Therapy Committee Task Group No. 66. Med Phys. 2003;30:2762-92.
Och JG, Clarke GD, Sobol WT, et al. Acceptance testing of magnetic resonance imaging systems: report of AAPM Nuclear Magnetic Resonance Task Group No. 6. Med Phys. 1992;19:217-29.
Lerski R, De Wilde J, Boyce D, Ridgeway J. Quality control in magnetic resonance imaging. IPEM Report 80. Institute of Physics and Engineering in Medicine, UK, 1999. ISBN 0-904181 901. European Journal of Radiology, 2000; 36:59- 60.
Walker A, Liney G, Holloway L, et al. Continuous table acquisition MRI for radiotherapy treatment planning: Distortion assessment with a new extended 3D volumetric phantom. Med Phys. 2015;42:1982-91.
Bedford J, Childs PJ, Nordmark Hansen V, et al. Commissioning and quality assurance of the Pinnacle3 radiotherapy treatment planning system for external beam photons. Br J Radiol. 2003;76:163-76.
Dempsey MF, Condon B, Hadley DM. MRI safety review. Semin Ultrasound CT MR. 2002; 23:392-401.
Liney GP, Holloway L, Al Harthi TM, et al. Quantitative evaluation of diffusion-weighted imaging techniques for the purposes of radiotherapy planning in the prostate. Br J Radiol. 2015;88:20150034.
Walker A, Liney G, Metcalfe P, Holloway L. MRI distortion: considerations for MRI based radiotherapy treatment planning. Australas Phys Eng Sci Med. 2014;37:103-13.
Vedam S, Docef A, Fix M, et al. Dosimetric impact of geometric errors due to respiratory motion prediction on dynamic multileaf collimator-based four-dimensional radiation delivery. Med Phys. 2005;32:1607-20.
Baldwin LN, Wachowicz K, Fallone BG. A two-step scheme for distortion rectification of magnetic resonance images. Medi phys. 2009; 36:3917-26.
Stanescu T, Jans HS, Wachowicz K, Fallone BG. Investigation of a 3D system distortion correction method for MR images. J Appl Clin Med Phys. 2010;11:2961.
Chen CC, Wan YL, Wai YY, Liu HL. Quality assurance of clinical MRI scanners using ACR MRI phantom: preliminary results. J Digit Imaging. 2004;17:279-84.
Ihalainen TM, Lonnroth NT, Peltonen JI, et al. MRI quality assurance using the ACR phantom in a multi-unit imaging center. Acta Oncol. 2011;50:966-72.
Keyriläinen J, Kapanen M, Seppälä T, et al. MRI-only based RTP workflow of prostate cancer patients. Int J Radiat Oncol Biol Phys. 2014;90:S929-30.
Brock KK, Dawson LA. Point: Principles of magnetic resonance imaging integration in a computed tomography–based radiotherapy workflow. Semin Radiat Oncol. 2014;24:169-74.
Andreasen D, Van Leemput K, Hansen RH, et al. Patch-based generation of a pseudo CT from conventional MRI sequences for MRI-only radiotherapy of the brain. Med phys. 2015; 42:1596-605.
Sun J, Dowling J, Pichler P, et al. MRI simulation: end-to-end testing for prostate radiation therapy using geometric pelvic MRI phantoms. Phys Med Biol. 2015;60:3097.
Friedman L, Glover GH. Report on a multicenter fMRI quality assurance protocol. J Magn Reson Imaging. 2006;23:827-39.
Firbank MJ, Harrison RM, Williams ED, Coulthard A. Quality assurance for MRI: practical experience. Br J Radiol. 2000; 73:376-83.
DOI: http://dx.doi.org/10.14319/ijcto.42.1
This work is licensed under a Creative Commons Attribution 3.0 License.
International Journal of Cancer Therapy and Oncology (ISSN 2330-4049)
© International Journal of Cancer Therapy and Oncology (IJCTO)
To make sure that you can receive messages from us, please add the 'ijcto.org' domain to your e-mail 'safe list'. If you do not receive e-mail in your 'inbox', check your 'bulk mail' or 'junk mail' folders.
Number of visits since October, 2013