Hostname: page-component-586b7cd67f-vdxz6 Total loading time: 0 Render date: 2024-11-23T22:30:50.708Z Has data issue: false hasContentIssue false

The rationale for MR-only delineation and planning: retrospective CT–MR registration and target volume analysis for prostate radiotherapy

Published online by Cambridge University Press:  30 April 2020

Arivarasan Ilamurugu
Affiliation:
Department of Radiation Oncology, Yashoda Hospitals, Hyderabad, India School of Advanced Sciences, Vellore Institute of Technology, Vellore, India
Anu Radha Chandrasekaran*
Affiliation:
School of Advanced Sciences, Vellore Institute of Technology, Vellore, India
*
Author for correspondence: Anu Radha Chandrasekaran, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu, India. Tel: +91 80088 97837. E-mail: [email protected]

Abstract

Aim:

Magnetic resonance imaging (MRI) is indispensable for treatment planning in prostate radiotherapy (PR). Registration of MRI when compared to planning CT (pCT) is prone to uncertainty and this is rarely reported. In this study, we have compared three different types of registration methods to justify the direct use of MRI in PR.

Methods and materials:

Thirty patients treated for PR were retrospectively selected for this study and all underwent both CT and MRI. The MR scans were registered to the pCT using markers, focused and unfocussed methods and their registration are REGM, REGF, and REGNF, respectively. Registration comparison is done using the translational differences of three axes from the centre-of-mass values of gross tumour volume (GTV) generated using MRI.

Results:

The average difference in all three axes (x, y, z) is (1, 2·5, 2·3 mm) and (1, 3, 2·3 mm) for REGF-REFNF and REGF-REGM, respectively. MR-based GTV Volume is less in comparison to CT-based GTV and it is significantly different (p < 0·001).

Findings:

Image registration uncertainty is unavoidable for a regular CT–MR workflow. Additional planning target volume margin ranging from 2 to 3mm could be avoided if MR-only workflow is employed. This reduction in the margin is beneficial for small tumours treated with hypofractionation.

Type
Original Article
Copyright
© The Author(s), 2020. Published by Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Rasch, C, Barillot, I, Remeijer, P, Touw, A, van Herk, M, Lebesque, JV. Definition of the prostate in CT and MRI: a multi-observer study. Int J Radiat Oncol Biol Phys 1999; 43 (1): 5766.CrossRefGoogle ScholarPubMed
Debois, M, Oyen, R, Maes, F et al. The contribution of magnetic resonance imaging to the three-dimensional treatment planning of localized prostate cancer. Int J Radiat Oncol Biol Phys 1999; 45 (4): 857865.CrossRefGoogle ScholarPubMed
Parker, CC, Damyanovich, A, Haycocks, T, Haider, M, Bayley, A, Catton, CN. Magnetic resonance imaging in the radiation treatment planning of localized prostate cancer using intra-prostatic fiducial markers for computed tomography co-registration. Radiother Oncol 2003; 66 (2): 217224.CrossRefGoogle ScholarPubMed
Ménard, C, Paulson, E, Nyholm, T et al. Role of prostate MR imaging in radiation oncology. Radiol Clin 2018; 56 (2): 319325.CrossRefGoogle ScholarPubMed
Ulin, K, Urie, MM, Cherlow, JM. Results of a multi-institutional benchmark test for cranial CT/MR image registration. Int J Radiat Oncol Biol Phys 2010; 77 (5): 15841589.CrossRefGoogle ScholarPubMed
Roberson, PL, McLaughlin, PW, Narayana, V, Troyer, S, Hixson, GV, Kessler, ML. Use and uncertainties of mutual information for computed tomography/magnetic resonance (CT/MR) registration post permanent implant of the prostate. Med Phys 2005; 32 (2): 473482.CrossRefGoogle ScholarPubMed
Hill, DL, Batchelor, PG, Holden, M, Hawkes, DJ. Medical image registration. Phys Med Biol 2001; 46 (3): R1.CrossRefGoogle ScholarPubMed
Villeirs, GM, De Meerleer, GO. Magnetic resonance imaging (MRI) anatomy of the prostate and application of MRI in radiotherapy planning. Eur J Radiol 2007; 63 (3): 361368.CrossRefGoogle ScholarPubMed
Khoo, VS, Padhani, AR, Tanner, SF, Finnigan, DJ, Leach, MO, Dearnaley, DP. Comparison of MRI with CT for the radiotherapy planning of prostate cancer: a feasibility study. Br J Radiol 1999; 72 (858): 590597.Google ScholarPubMed
Moseley, DJ, White, EA, Wiltshire, KL et al. Comparison of localization performance with implanted fiducial markers and cone-beam computed tomography for on-line image-guided radiotherapy of the prostate. Int J Radiat Oncol Biol Phys 2007; 67 (3): 942953.CrossRefGoogle ScholarPubMed
Murray, J, Tree, A. Prostate cancer–advantages and disadvantages of MR-guided RT. Clin Transl Radiat Oncol 2019; 18: 6873.CrossRefGoogle Scholar
Njeh, CF, Parker, BC. 1.15. Implanted fiducial markers are no longer needed for prostate cancer radiotherapy. In: Controversies in Medical Physics: a Compendium of Point/Counterpoint Debates, Volume 3, 2017: 94.Google Scholar
Deegan, T, Owen, R, Holt, T, et al. Assessment of cone beam CT registration for prostate radiation therapy: Fiducial marker and soft tissue methods. J Med Imaging Radiat Oncol 2015; 59 (1): 9198.Google ScholarPubMed
Henderson, D, Tree, A, Harrington, K, van As, N. Dosimetric implications of computerised tomography-only versus magnetic resonance-fusion contouring in stereotactic body radiotherapy for prostate cancer. Medicines 2018; 5 (2): 32.CrossRefGoogle ScholarPubMed
Deegan, T, Owen, R, Holt, T et al. Interobserver variability of radiation therapists aligning to fiducial markers for prostate radiation therapy. J Med Imaging Radiat Oncol 2013; 57 (4): 519523.CrossRefGoogle ScholarPubMed
Khalifa, J, Commandeur, F, Bachaud, JM. Choice of optimal margins in prostate conformal radiotherapy. Cancer Radiother 2013; 17 (5–6): 461469.CrossRefGoogle ScholarPubMed
Salembier, C, Villeirs, G, De Bari, B et al. ESTRO ACROP consensus guideline on CT-and MRI-based target volume delineation for primary radiation therapy of localized prostate cancer. Radiother Oncol 2018; 127 (1): 4961.CrossRefGoogle ScholarPubMed
Prete, JJ, Prestidge, BR, Bice, WS, Dubois, DF, Hotchkiss, LA. Comparison of MRI-and CT-based post-implant dosimetric analysis of transperineal interstitial permanent prostate brachytherapy. Radiat Oncol Investig Clin Basic Res 1998; 6 (2): 9096.3.0.CO;2-C>CrossRefGoogle ScholarPubMed
Arivarasan, I, Anuradha, C, Subramanian, S, Anantharaman, A, Ramasubramanian, V. Magnetic resonance image guidance in external beam radiation therapy planning and delivery. Japanese J Radiol 2017; 35 (8): 417426.Google Scholar
Jonsson, J, Nyholm, T, Söderkvist, K. The rationale for MR-only treatment planning for external radiotherapy. Clin Transl Radiat Oncol 2019: 18; 6667.Google ScholarPubMed
Sandler, HM, Liu, PY, Dunn, RL et al. Reduction in patient-reported acute morbidity in prostate cancer patients treated with 81-Gy Intensity-modulated radiotherapy using reduced planning target volume margins and electromagnetic tracking: assessing the impact of margin reduction study. Urology 2010; 75 (5): 10041008.CrossRefGoogle ScholarPubMed
Pérez-Romasanta, LA, Lozano-Martín, E, Velasco-Jiménez, J et al. CTV to PTV margins for prostate irradiation. Three-dimensional quantitative assessment of interfraction uncertainties using portal imaging and serial CT scans. Clin Transl Oncol 2009; 11 (9): 615621.CrossRefGoogle ScholarPubMed
Walker, A, Liney, G, Metcalfe, P, Holloway, L. MRI distortion: considerations for MRI based radiotherapy treatment planning. Australas Phys Eng Sci Med 2014; 37 (1): 103113.CrossRefGoogle ScholarPubMed
Adjeiwaah, M, Bylund, M, Lundman, JA, Karlsson, CT, Jonsson, JH, Nyholm, T. Quantifying the effect of 3T magnetic resonance imaging residual system distortions and patient-induced susceptibility distortions on radiation therapy treatment planning for prostate cancer. Int J Radiat Oncol Biol Phys 2018; 100 (2): 317324.CrossRefGoogle ScholarPubMed
Khoo, VS, Dearnaley, DP, Finnigan, DJ, Padhani, A, Tanner, SF, Leach, MO. Magnetic resonance imaging (MRI): considerations and applications in radiotherapy treatment planning. Radiother Oncol 1997; 42 (1): 15.CrossRefGoogle Scholar