Optical system for precise isocenter measurement

• Autorzy: Kukołowicz Paweł , Szalkowski Dariusz , Jackowska-Zduniak Beata , Tarchalski Mikołaj

Identyfikatory

DOI

10.2478/pjmpe-2023-0019

• Języki publikacji: EN

Abstrakty

EN

Introduction: The geometrical precision of the machines is essential for effective and safe radiotherapy. Methods currently used for the measurement of the mechanical isocenter have many limitations. In this work, the optical system NaviRation for very precise measurement of mechanical accelerator isocenter is described. The results of the measurement of the isocenter for linear accelerator are also presented. Materials and methods: An optical system for measuring the accelerator isocenter was designed and built. The optical system consists of two cameras recording the target position made according to a patented Zeiss technology. About 1,200 pairs of images are recorded during the rotation of the gantry, collimator and treatment table. Mathematical analysis of these images makes it possible to determine the location of the target center during rotation. In order to verify the accuracy of the measurements, a device simulating rotational motion was designed. The measurement results were also verified at the Central Office of Measures. The system must be calibrated each time before taking measurements. In this article, we present the results of measurements for the Versa HD accelerator. Results: The accuracy of determining the current position of the axis of rotation was 0.15 mm. The time of taking measurements of all rotations does not exceed 20 minutes. Measurement results for the Versa HD accelerator showed that this accelerator met the criteria described by TG142 of the AAPM. The diameter of the gantry, collimator and table isocenter spheres were 1.5 mm, 0.3 mm and 0.4 mm, respectively. Conclusions: The system enables precise, fast and simple mechanical isocenter measurement of the gantry, collimator and treatment table. It is also possible to perform all tests related to the measurements of distances, e.g. quality control of distance indicator, and distance of the table movement. The isocenter is measured independently of the accelerator for which measurements are made.

Słowa kluczowe

EN

quality control; optical system; accelerator isocenter

• Wydawca: Polskie Towarzystwo Fizyki Medycznej ; De Gruyter
• Czasopismo: Polish Journal of Medical Physics and Engineering
• Rocznik: 2023
• Tom: Vol. 29, Iss. 4
• Strony: 178--184
• Opis fizyczny: Bibliogr. 11 poz., rys., tab.

Twórcy

autor

Kukołowicz Paweł

• Medical Physics Department, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland

autor

Szalkowski Dariusz

• NaviRation LLC, Poland

autor

Jackowska-Zduniak Beata

• Institute of Information Technology, Warsaw University of Life Sciences, Poland

autor

Tarchalski Mikołaj

• NaviRation LLC, Poland

Bibliografia

• 1. Klein EE, Hanley J, Bayouth J, et al. Task Group 142 report: Quality assurance of medical accelerators. Med Phys. 2009;36(9Part1):4197-4212. https://doi.org/10.1118/1.3190392
• 2. Tsai J-S, Curran BH, Sternick ES, Engler MJ. The measurement of linear accelerator isocenter motion using a three-micrometer device and an adjustable pointer. Int J Radiat Oncol. 1996;34(1):189-195. https://doi.org/10.1016/0360-3016(95)02085-3
• 3. Hanley J, Dresser S, Simon W, et al. AAPM Task Group 198 Report: An implementation guide for TG 142 quality assurance of medical accelerators. 2021;48(10):e830-e885. https://doi.org/10.1002/mp.14992
• 4. Doudard A, Guérin C, Dufreneix S, Josset S. Design and automation of specific geometric quality controls for cone-radiosurgery treatments. Phys Med. 2022;96:1-8. https://doi.org/10.1016/j.ejmp.2022.02.011
• 5. Bodjanski M, inventor; Carl Zeiss IQS Software R&D Center Sp zoo, assignee. Optical tracking method and system based on passive markers. U.S. Patent No. US 2017 / 0258531 A1. September 14, 2017.
• 6. Zhang M , Zhou S, Qu T. What Do We Mean When We Talk about the Linac Isocenter? International Journal of Medical Physics, Clinical Engineering and Radiation Oncology. 2015;4(3):233-242. https://doi.org/10.4236/ijmpcero.2015.43028
• 7. Calibration Certificate Z3-Z33.4180.167.2023.1888.4, Central Office of Measures (COM, Poland)
• 8. Lutz W, Winston KR, Maleki N. A system for stereotactic radiosurgery with a linear accelerator. Int J Radiat Oncol Biol Phys. 1988;14(2):373-381. https://doi.org/10.1016/0360-3016(88)90446-4
• 9. Skworcow P, Mills JA, Haas OC, Burnham KJ. A new approach to quantify the mechanical and radiation isocentres of radiotherapy treatment machine gantries. Phys Med Biol. 2007;52(23):7109-7124. https://doi.org/10.1088/0031-9155/52/23/022
• 10. Heikkilä J, Seppälä J, Nuutinen, Vanne A, Lahtinen T. A photographic technique for quick assessment of mechanical isocenter of a linear accelerator. Technical Innovations & Patient Support in Radiation Oncology. 2017;2(1-4). https://doi.org/10.1016/j.tipsro.2017.03.001
• 11. Chojnowski JM, Sykes JR, Thwaites DI. A novel method to determine linac mechanical isocenter position and size and example of specific QA application. J Appl Clin Med Phys. 2021;22(7):44-55. https://doi.org/10.1002/acm2.13257

Uwagi

Opracowanie rekordu ze środków MNiSW, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2024).