Dosimetric analysis of the cone beam-focused gamma knife

Abstract

This study presents the first report on the fundamental dosimetric characterization of a novel image-guided radiosurgery system - the ZND-A Smart Knife (CNCI Co., Ltd, Xi’an, China). The dosimetric performance of this radiosurgery system was evaluated based on key parameters, including positioning reference point deviation, nominal focal point dose rate, focusing field size, dose gradient, and comprehensive error in dose calculation. The system employs “triple rotating and focusing” technique, and its dosimetric characteristics were measured. The maximum positioning reference point deviation for collimator #1 - 4 was 0.38 mm; the corresponding dose gradients were 3.1 mm, 3.4 mm, 5.4 mm, and 7.7 mm, respectively. In dose calculation, the maximum isocenter point dose deviation was 3.3%, and the area overlap ratio for the largest collimator (#4) reached 98.3%. These results demonstrate excellent dosimetric performance and clinical potential, confirming the safety and precision of the next-generation cone beam-focused gamma knife system.

Keywords

Cone beam-focused gamma knife / EBT3 film / Electrostatic meter / Radiation dosimetry / Stereotactic radiation therapy

Acknowledgments

The authors acknowledge the assistance received from Qi-Xing Han of CNNC Cheng Imaging (Xi’an) Medical Equipment Company, for the English translation of this article.

Funding

This research is funded by the CNNC research project “Smart Cobalt 60 cone beam-focused SRT system research and development”.

Conflict of interest

All the authors are employees of CNNC.

Author contributions

Conceptualization: Shan-Chuan Li, Shao-Run Gong, Gang Li, Chun-Li Zhang, Jun Li

Formal analysis: Feng Zhang, Shuang Zhang

Investigation: Shan-Chuan Li, Xiao-Feng Zhang, Feng Zhang, Jun-Feng Wang, Shuang Zhang

Methodology: Shan-Chuan Li, Feng Zhang, Shuang Zhang

Writing - original draft: Shan-Chuan Li, Feng Zhang, Shuang Zhang

Writing - review & editing: Feng Zhang, Jun-Feng Wang

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Availability of data

Data are available from the corresponding author upon reasonable request.

References

[1] Qiu HB, Cao SM, Xu RH. An analysis of the temporal trends of cancer incidence, mortality, and burden in China based on global epidemiological data from 2020, with comparisons to data from the United States and the United Kingdom. Cancer. 2022; 41(4):165-177. doi: 10.3321/j.issn.1000-467X.2022.4.ez202204003

[2] Heck B, Jess‐Hempen A, Kreiner HJ, Schopgens H, Mack A. Accuracy and stability of positioning in radiosurgery: Longterm results of the Gamma Knife system. Med Phys. 2007; 34(4):1487-1495. doi: 10.1118/1.2710949

[3] Aland T, Kairn T, Kenny J. Evaluation of a Gafchromic EBT2 film dosimetry system for radiotherapy quality assurance. Australas Phys Eng Sci Med. 2011; 34(2):251-260. doi: 10.1007/s13246-011-0072-6

[4] Cao HB. The Dosimetric Study of Body Gamma Knife. Master’s Thesis. Tsinghua University; 2015. Available from: https://cdmd.cnki.com.cn/Article/CDMD-10003-1015007280.htm [Last accessed on 2024 May 10].

[5] Xu H, Liu M, Zhao QJ, Zheng Y, Lu JR. Applied research of Gamma knife detecting technique based on ImageL. China Med Equip. 2021; 18(3):24-29. doi: 10.3969/J.ISSN.1672-8270.2021.03.006

[6] Watanabe Y, Akimitsu T, Hirokawa Y, Mooij RB, Perera GM. Evaluation of dose delivery accuracy of Gamma Knife by polymer gel dosimetry. J Appl Clin Med Phys. 2005; 6(3): 133-142. doi: 10.1120/jacmp.v6i3.2110

[7] Mao K, Kang J, Dai T, Han Y, Wang Z. Quality control of gamma ray stereotactic radiotherapy. China Med Equip. 2015;(10):30-31, 32. doi: 10.3969/J.ISSN.1672-8270.2015.10.009

[8] Pai S, Das IJ, Dempsey JF, et al. TG‐69: Radiographic film for megavoltage beam dosimetry. Med Phys. 2007; 34(6 Part1):2228-2258. doi: 10.1118/1.2736779

[9] International Atomic Energy Agency. Tehnical Report of Series no. 277 Absorbed Dose Determination in Photon and Electron Beams-An international Code of Practice. 2nd ed. Austria: International Atomic Energy Agency; 1997.

[10] National Technical Committee for Standardization of Medical Electrical Equipment, Subcommittee on Radiotherapy, Nuclear Medicine and Radiation Dosimetry Equipment (SAC/TC 10/SC 3). YY 0831.1-2011, Stereotactic Radiotherapy System with Gamma Beam-Part 1: Multi- Source Stereotactic Radiotherapy System with Gamma Beam for Head Lesion. China: State Food and Drug Administration; 2011.

[11] National Technical Committee for Standardization of Medical Electrical Equipment, Subcommittee on Radiotherapy, Nuclear Medicine and Radiation Dosimetry Equipment (SAC/TC 10/SC 3). YY 0831.2-2015, Stereotactic Radiotherapy System with Gamma Beam-Part 2: Multi- Source Stereotactic Radiotherapy System with Gamma Beam for Body Lesion. China: State Food and Drug Administration; 2011.

[12] Tham BZ, Aleman DM, Heaton RK, Nordstrom H, Coolens C. Physical dose validation of dynamic treatment for Gamma Knife radiosurgery. Med Phys. 2024; 51(5):3635-3647. doi: 10.1002/mp.17034

[13] Choi Y, Chun KJ, Kim ES, et al. Consistency of dose rates after applying machine-specific reference correction factors for the gamma knife 16 mm collimator field. Med Phys. 2023; 50(6):3816-3824. doi: 10.1002/mp.16242

[14] Kim TH, Yang HJ, Jeong JY, et al. Feasibility of isodoseshaped scintillation detectors for the measurement of gamma knife output factors. Med Phys. 2022; 49(3): 1944-1954. doi: 10.1002/mp.15469

[15] Mora G, Chibani O, Li J, Ma C. SU-E-T-605: A New Design for a Rotating Gamma Knife. Monte Carlo Simulation. Poster Presented at: Fifty-Sixth annual meeting of the American Association of Physicists in Medicine, Austin, Texas; 2014.

[16] National Technical Committee on Ionizing Radiation Metrology. JJG 1013-2006, Verification Regulation of γ Radiation Source Used in Head Stereotactic. Radiosurgery Therapy. China: General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China; 2006.

[17] National Health and Family Planning Commission of the People’s Republic of China. WS 582-2017, Specifications for Testing of Quality Control in X and Γ Ray Stereotactic Radiotherapy System. Beijing: National Health and Family Planning Commission of the People’s Republic of China; 2017.