Comisionado de un MR-linac Elekta Unity
DOI:
https://doi.org/10.37004/sefm/2024.25.1.002Palabras clave:
Comisionado, MR-Linac, Unity, radioterapia adaptativaResumen
La combinación de un acelerador lineal con un equipo de resonancia magnética ha dado lugar a los sistemas de radioterapia guiada por imagen de resonancia magnética, denominados MR-linac. Estos equipos aprovechan la imagen de resonancia magnética para localizar el tumor y la posición de los órganos sanos y hacen posible adaptar el plan de tratamiento en cada fracción, además de poder visualizar la anatomía del paciente durante el tratamiento, mientras tiene lugar la irradiación. La combinación de ambos equipos añade cierta complejidad al proceso de comisionado. Este trabajo describe las medidas que se realizaron durante el comisionado de un MR-linac Unity, las correspondientes al acelerador lineal, a la resonancia magnética, y a la combinación de ambos equipos. Todos los resultados de las medidas cumplieron las tolerancias establecidas, y tan sólo se requirió una mejora en la exactitud de la posición del MLC. Las pruebas de funcionamiento del sistema con tratamientos de IMRT superaron el índice gamma 3%/3 mm y 5% de valor umbral de fondo con valores superiores al 95% mientras que la medida con cámara de ionización se diferenció un máximo de 0.87% respecto de la calculada por el TPS.
Referencias
Franzone P, Fiorentino A, Barra S, et al. Image-guided radiation therapy (IGRT): practical recommendations of Italian Association of Radiation Oncology (AIRO). Radiol Medica. 2016;121(12):958-965. https://doi.org/10.1007/s11547-016-0674-x
Raaymakers BW, Raaijmakers AJE, Kotte ANTJ, Jette D, Lagendijk JJW. Integrating a MRI scanner with a 6 MV radiotherapy accelerator: Dose deposition in a transverse magnetic field. Phys Med Biol. 2004;49(17):4109-4118. https://doi.org/10.1088/0031-9155/49/17/019
Raaymakers B, Lagendijk J, Overweg J, et al. Integrated 1.5 T Mri and Accelerator: Proof of Concept for Real-Tim E Mri Guided Radiotherapy. Radiother Oncol. 2009;92:S33. https://doi.org/10.1016/s0167-8140(12)72672-5
Raaymakers BW, Jürgenliemk-Schulz IM, Bol GH, et al. First patients treated with a 1.5 T MRI-Linac: Clinical proof of concept of a high-precision, high-field MRI guided radiotherapy treatment. Phys Med Biol. 2017;62(23):L41-L50. https://doi.org/10.1088/1361-6560/aa9517
Lagendijk JJW, Raaymakers BW, Raaijmakers AJE, et al. MRI/linac integration. Radiother Oncol. 2008;86(1):25-29. https://doi.org/10.1016/j.radonc.2007.10.034
Winkel D, Bol GH, Kroon PS, et al. Adaptive radiotherapy: The Elekta Unity MR-linac concept. Clin Transl Radiat Oncol. 2019;18:54-59. https://doi.org/10.1016/j.ctro.2019.04.001
Kapanen M, Collan J, Beule A, Seppälä T, Saarilahti K, Tenhunen M. Commissioning of MRI-only based treatment planning procedure for external beam radiotherapy of prostate. Magn Reson Med. 2013;70(1). https://doi.org/10.1002/mrm.24459
Liney GP, Owen SC, Beaumont AKE, Lazar VR, Manton DJ, Beavis AW. Commissioning of a new wide-bore MRI scanner for radiotherapy planning of head and neck cancer. Br J Radiol. 2013;86(1027). https://doi.org/10.1259/bjr.20130150
Meijsing I, Raaymakers BW, Raaijmakers AJE, et al. Dosimetry for the MRI accelerator: The impact of a magnetic field on the response of a Farmer NE2571 ionization chamber. Phys Med Biol. 2009;54(10):2993-3002. https://doi.org/10.1088/0031-9155/54/10/002
Malkov VN, Hackett SL, Wolthaus JWH, Raaymakers BW, Van Asselen B. Monte Carlo simulations of out-of-field surface doses due to the electron streaming effect in orthogonal magnetic fields. Phys Med Biol. 2019;64(11). https://doi.org/10.1088/1361-6560/ab0aa0
Raaijmakers AJE, Raaymakers BW, Lagendijk JJW. Integrating a MRI scanner with a 6 MV radiotherapy accelerator: Dose increase at tissue-air interfaces in a lateral magnetic field due to returning electrons. Phys Med Biol. 2005;50(7). https://doi.org/10.1088/0031-9155/50/7/002
Klein EE, Hanley J, Bayouth J, et al. Task group 142 report: Quality assurance of medical accelerators. Med Phys. 2009;36(9):4197-4212. https://doi.org/10.1118/1.3190392
Das IJ, Cheng C-WW, Watts RJ, et al. Accelerator beam data commissioning equipment and procedures: Report of the TG-106 of the Therapy Physics Committee of the AAPM. Med Phys. 2008;35(9):4186-4215. https://doi.org/10.1118/1.2969070
Glide-Hurst C, Bellon M, Foster R, et al. Commissioning of the Varian TrueBeam linear accelerator: A multi-institutional study. Med Phys. 2013;40(3). https://doi.org/10.1118/1.4790563
Narayanasamy G, Saenz D, Cruz W, Ha CS, Papanikolaou N, Stathakis S. Commissioning an Elekta Versa HD linear accelerator. J Appl Clin Med Phys. 2016;17(1):179-191. https://doi.org/10.1120/jacmp.v17i1.5799
Snyder JE, St-Aubin J, Yaddanapudi S, et al. Commissioning of a 1.5T Elekta Unity MR-linac: A single institution experience. J Appl Clin Med Phys. 2020;21(7):160-172. https://doi.org/10.1002/acm2.12902
Powers M, Baines J, Crane R, et al. Commissioning measurements on an Elekta Unity MR-Linac. Phys Eng Sci Med. 2022;45(2). https://doi.org/10.1007/s13246-022-01113-7
Subashi E, Dresner A, Tyagi N. Longitudinal assessment of quality assurance measurements in a 1.5T MR-linac: Part II—Magnetic resonance imaging. J Appl Clin Med Phys. 2022;23(6). https://doi.org/10.1002/acm2.13586
Subashi E, Lim SB, Gonzalez X, Tyagi N. Longitudinal assessment of quality assurance measurements in a 1.5T MR-linac: Part I—Linear accelerator. J Appl Clin Med Phys. 2021;22(10):190-201. https://doi.org/10.1002/acm2.13418
Roberts DA, Sandin C, Vesanen PT, et al. Machine QA for the Elekta Unity system: A Report from the Elekta MR-linac consortium. Med Phys. 2021;48(5). https://doi.org/10.1002/mp.14764
Woodings SJ, Bluemink JJ, De Vries JHW, et al. Beam characterisation of the 1.5 T MRI-linac. Phys Med Biol. 2018;63(8). https://doi.org/10.1088/1361-6560/aab566
Woodings SJ, de Vries JHW, Kok JMG, et al. Acceptance procedure for the linear accelerator component of the 1.5 T MRI-linac. J Appl Clin Med Phys. 2021;22(8). https://doi.org/10.1002/acm2.13068
Hanley J, Dresser S, Simon W, et al. AAPM Task Group 198 Report: An implementation guide for TG 142 quality assurance of medical accelerators. Med Phys. 2021;48(10):e830-e885. https://doi.org/10.1002/mp.14992
Almond PR, Biggs PJ, Coursey BM, et al. AAPM’s TG-51 protocol for clinical reference dosimetry of high-energy photon and electron beams. Med Phys. 1999;26(9):1847-1870. https://doi.org/10.1118/1.598691
IAEA TRS 483. Dosimetry of Small Static Fields Used in External Beam Radiotherapy: An IAEA-AAPM International Code of Practice for Reference and Relative Dose Determination. In: Technical Report Series No. 483. International Atomic Energy Agency. Vienna, Austria; 2017.
Andreo P, Burns DT, Hohlfeld K, et al. IAEA TRS-398 Absorbed Dose Determination in External Beam Radiotherapy: An International Code of Practice for Dosimetry Based on Standards of Absorbed Dose to Water.; 2000.
International atomic energy agency. Quality Assurance in Radiotherapy, IAEA-TECDOC-989. IAEA, Vienna; 1998.
Patel I, Weston J, Palmer A. Physics Aspects of Quality Control in Radiotherapy (IPEM Report 81, 2nd Edition).; 2018.
Van der Wal E, Wiersma J, Ausma AH, et al. NCS Report 22: Code of Practice for the Quality Assurance and Control for Intensity Modulated Radiotherapy.; 2013.
Romero RR, Rincón CM, Moral Sánchez S, Rubio PS, Sevillano Martínez D. Procedimientos recomendados para el control de calidad de IMRT en tomoterapia. Rev Fis Med. 2018;19(2):73-102.
Netherton T, Li Y, Gao S, et al. Experience in commissioning the halcyon linac. Med Phys. 2019;46(10):4304-4313. https://doi.org/10.1002/mp.13723
Tijssen RHN, Philippens MEP, Paulson ES, et al. MRI commissioning of 1.5T MR-linac systems – a multi-institutional study. Radiother Oncol. 2019;132:114-120. https://doi.org/10.1016/j.radonc.2018.12.011
Jackson E, Bronskill M, Drost D, et al. AAPM n°100 - Acceptance Testing and Quality Assurance Procedures for Magnetic Resonance Imaging Facilities.; 2010.
Price R, Allison J, Clarke G, et al. Magnetic Resonance Imaging Quality Control Manual 2015. Am Coll Radiol. Published online 2015:120.
Steinmann A, O’Brien D, Stafford R, et al. Investigation of TLD and EBT3 performance under the presence of 1.5T, 0.35T, and 0T magnetic field strengths in MR/CT visible materials. Med Phys. 2019;46(7):3217-3226. https://doi.org/10.1002/mp.13527
Miften M, Olch A, Mihailidis D, et al. Tolerance limits and methodologies for IMRT measurement-based verification QA: Recommendations of AAPM Task Group No. 218. Med Phys. 2018;45(4):e53-e83. https://doi.org/10.1002/mp.12810
Chavhan GB, Babyn PS, Jankharia BG, Cheng HLM, Shroff MM. Steady-state MR imaging sequences: Physics, classification, and clinical applications. Radiographics. 2008;28(4):1147-1160. https://doi.org/10.1148/rg.284075031
NEMA. Determination of Signal-to-Noise Ratio (SNR) in Diagnostic Magnetic Resonance Imaging. NEMA Stand Publ MS 1-2008. Published online 2008.
NEMA. Determination of Image Uniformity in Diagnostic Magnetic Resonance Images. NEMA Stand Publ MS-3-2008. Published online 2008.
NEMA. Determination of Slice Thickness in Diagnostic Magnetic Resonance Imaging. NEMA Stand Publ MS-5-2008. Published online 2008.
De Roover R, Crijns W, Poels K, et al. Validation and IMRT/VMAT delivery quality of a preconfigured fast-rotating O-ring linac system. Med Phys. 2019;46(1):328-339. https://doi.org/10.1002/mp.13282
Bedford JL, Thomas MDR, Smyth G. Beam modeling and VMAT performance with the Agility 160-leaf multileaf collimator. J Appl Clin Med Phys. 2013;14(2):172-185. https://doi.org/10.1120/jacmp.v14i2.4136
Barten DLJ, Hoffmans D, Palacios MA, Heukelom S, Van Battum LJ. Suitability of EBT3 GafChromic film for quality assurance in MR-guided radiotherapy at 0.35 T with and without real-time MR imaging. Phys Med Biol. 2018;63(16). https://doi.org/10.1088/1361-6560/aad58d
Lee HJ, Kadbi M, Bosco G, Ibbott GS. Real-time volumetric relative dosimetry for magnetic resonance - Image-guided radiation therapy (MR-IGRT). Phys Med Biol. 2018;63(4). https://doi.org/10.1088/1361-6560/aaac22
Van Asselen B, Woodings SJ, Hackett SL, et al. A formalism for reference dosimetry in photon beams in the presence of a magnetic field. Phys Med Biol. 2018;63(12). https://doi.org/10.1088/1361-6560/aac70e
O’Brien DJ, Roberts DA, Ibbott GS, Sawakuchi GO. Reference dosimetry in magnetic fields: formalism and ionization chamber correction factors. Med Phys. 2016;43(8):4915-4927. https://doi.org/10.1118/1.4959785
Andreo P, Burns DT, Hohlfeld K, et al. IAEA TRS-398 Absorbed dose determination in external beam radiotherapy: An International code of practice for dosimetry based on standards of absorbed dose to water. Int At Energy Agency. Published online 2000.
Kalach NI, Rogers DWO. Which accelerator photon beams are “clinic-like” for reference dosimetry purposes? Med Phys. 2003;30(7):1546-1555. https://doi.org/10.1118/1.1573205
O’Brien DJ, Dolan J, Pencea S, Schupp N, Sawakuchi GO. Relative dosimetry with an MR-linac: Response of ion chambers, diamond, and diode detectors for off-axis, depth dose, and output factor measurements: Response. Med Phys. 2018;45(2):884-897. https://doi.org/10.1002/mp.12699
Cervantes Y, Duchaine J, Billas I, Duane S, Bouchard H. Monte Carlo calculation of detector perturbation and quality correction factors in a 1.5 T magnetic resonance guided radiation therapy small photon beams. Phys Med Biol. 2021;66(22). https://doi.org/10.1088/1361-6560/ac3344
Smilowitz JB, Das IJ, Feygelman V, et al. AAPM Medical Physics Practice Guideline 5.a.: Commissioning and QA of Treatment Planning Dose Calculations - Megavoltage Photon and Electron Beams. J Appl Clin Med Phys. 2015;16(5):14-34. https://doi.org/10.1120/jacmp.v16i5.5768
Aalbers AHL, Hoornaert MT, Minken A, Palmans H. NCS-18: Code of Practice for the Absorbed Dose Determination in High Energy Photon and Electron Beams.; 2012.
AAPM I. Dosimetry of small fields used in external beam radiotherapy. Int At Energy Agency Tech Reports Ser. 2017;483(5002):1138-1138.
Ezzell GA, Burmeister JW, Dogan N, et al. IMRT commissioning: Multiple institution planning and dosimetry comparisons, a report from AAPM Task Group 119. Med Phys. 2009;36(11):5359-5373. https://doi.org/10.1118/1.3238104
Hissoiny S, Ozell B, Bouchard H, Despŕs P. GPUMCD: A new GPU-oriented Monte Carlo dose calculation platform. Med Phys. 2011;38(2):754-764. https://doi.org/10.1118/1.3539725
De Pooter J, Billas I, De Prez L, et al. Reference dosimetry in MRI-linacs: evaluation of available protocols and data to establish a Code of Practice. Phys Med Biol. 2021;66(5). https://doi.org/10.1088/1361-6560/ab9efe
Liu C, Li M, Xiao H, et al. Advances in MRI-guided precision radiotherapy. Precis Radiat Oncol. 2022;6(1):75-84. https://doi.org/10.1002/pro6.1143
Tsuneda M, Abe K, Fujita Y, Ikeda Y, Furuyama Y, Uno T. Elekta Unity MR-linac commissioning: mechanical and dosimetry tests. J Radiat Res. 2023;64(1):73-84. https://doi.org/10.1093/jrr/rrac072
Geurts MW, Jacqmin DJ, Jones LE, et al. AAPM Medical Physics Practice Guideline 5.b: Commissioning and QA of treatment planning dose calculations—Megavoltage photon and electron beams. J Appl Clin Med Phys. 2022;23(9). https://doi.org/10.1002/acm2.13641
