Verification of electron beam parameters in an intraoperative linear accelerator using dosimetric and radiobiological response methods
Abstract
Background: The availability of linear accelerators (linac) for research purposes is often limited and therefore alternative radiation sources are needed to conduct radiobiological research. The National Centre for Radiation Research in Poland recently developed an intraoperative mobile linac that enables electron irradiation at energies ranging from 4 to 12 MeV and dose rates of 5 or 10 Gy/min. The present study was conducted to evaluate the electron beam parameters of this intraoperative linac and to verify the set-up to evaluate out-of-field doses in a water phantom, which were determined through dosimetric and biological response measurements.
Materials and methods: The distribution of radiation doses along and across the radiation beam were measured in a water phantom using a semiconductor detector and absolute doses using an ionisation chamber. Two luminal breast cancer cell lines (T-47D and HER2 positive SK-BR-3) were placed in the phantom to study radiation response at doses ranging from 2 to 10 Gy. Cell response was measured by clonogenic assays.
Results and Conclusion: The electron beam properties, including depth doses and profiles, were within expected range for the stated energies. These results confirm the viability of this device and set-up as a source of megavoltage electrons to evaluate the radiobiological response of tumour cells.
Keywords: electron acceleratorintraoperative radiotherapybreast cancerclonogenic assay
References
- Ronga MG, Cavallone M, Patriarca A, et al. Back to the Future: Very High-Energy Electrons (VHEEs) and Their Potential Application in Radiation Therapy. Cancers (Basel). 2021; 13(19).
- Moeckli R, Gonçalves Jorge P, Grilj V, et al. Commissioning of an ultra-high dose rate pulsed electron beam medical LINAC for FLASH RT preclinical animal experiments and future clinical human protocols. Med Phys. 2021; 48(6): 3134–3142.
- Fastner G, Gaisberger C, Kaiser J, et al. ESTRO IORT Task Force/ACROP recommendations for intraoperative radiation therapy with electrons (IOERT) in breast cancer. Radiother Oncol. 2020; 149: 150–157.
- Piotrowski I, Kulcenty K, Murawa D, et al. Biologiczne aspekty śródoperacyjnej radioterapii i roli płynów pooperacyjnych w terapii raka piersi. Lett Oncol Sci. 2016; 13(2): 30–37.
- Piotrowski I, Kulcenty K, Wichtowski M, et al. Intraoperative Radiotherapy of Breast Cancer and Its Biological Effects. Breast Care (Basel). 2017; 12(2): 109–113.
- Minafra L, Bravatà V, Russo G, et al. Gene Expression Profiling of MCF10A Breast Epithelial Cells Exposed to IOERT. Anticancer Res. 2015; 35(6): 3223–3234.
- Bravatà V, Minafra L, Russo G, et al. High-dose Ionizing Radiation Regulates Gene Expression Changes in the MCF7 Breast Cancer Cell Line. Anticancer Res. 2015; 35(5): 2577–2591.
- Piotrowski I, Kulcenty K, Murawa D, et al. Surgical wound fluids from patients treated with intraoperative radiotherapy induce radiobiological response in breast cancer cells. Med Oncol. 2018; 36(2): 14.
- Iktueren B, Bilge H, Karacam S, et al. The peripheral dose outside the applicator in electron beams of Oncor linear accelerator. Radiat Prot Dosimetry. 2012; 150(2): 192–197.
- Haghparast A, Amiri F, Yarahmadi M, et al. The peripheral dose outside the applicator in electron beams of an Elekta linear accelerator. Australas Phys Eng Sci Med. 2018; 41(3): 647–655.
- Chow JCL, Grigorov GN. Peripheral dose outside applicators in electron beams. Phys Med Biol. 2006; 51(12): N231–N240.
- Jabbari N, Hashemi-Malayeri B, Farajollahi AR, et al. Monte Carlo calculation of scattered radiation from applicators in low energy clinical electron beams. Nukleonika. 2007; 52: 97–103.
- Perec A, Kubo H. Radiation leakage through electron applicators on Clinac-1800 accelerators. Med Phys. 1990; 17(4): 715–719.
- Alabdoaburas MM, Mege JP, Chavaudra J, et al. Experimental assessment of out-of-field dose components in high energy electron beams used in external beam radiotherapy. J Appl Clin Med Phys. 2015; 16(6): 435–448.
- Adrich P. Technical Note: Monte Carlo study on the reduction in x-ray contamination of therapeutic electron beams for Intraoperative Radiation Therapy by means of improvements in the design of scattering foils. Med Phys. 2019; 46(8): 3378–3384.
- García-Cases F, Perez-Calatayud J, Ballester F, et al. Peripheral dose around a mobile linac for intraoperative radiotherapy: radiation protection aspects. J Radiol Prot. 2018; 38(4): 1393–1411.
- Mahdavi SR, Tutuni M, Farhood B, et al. Measurement of peripheral dose to the pelvic region and the associated risk for cancer development after breast intraoperative electron radiation therapy. J Radiol Prot. 2019; 39(1): 278–291.
- Matuszak N, Suchorska WM, Milecki P, et al. FLASH Radiotherapy: an emerging approach in radiation therapy. Rep Pract Oncol Radiother. 2021; in print.
- Scharf W. Akceleratory biomedyczne. Wydawnictwo Naukowe PWN, Warszawa 1994.
- Pracz J, Syntfeld-Każuch A. Akcelerator IntraLine–IORT do radioterapii śródoperacyjnej. Post Tech Jądr. 2017; 60(3): 21–28.
- Scalchi P, Ciccotelli A, Felici G, et al. Use of parallel-plate ionization chambers in reference dosimetry of NOVAC and LIAC mobile electron linear accelerators for intraoperative radiotherapy: a multi-center survey. Med Phys. 2017; 44(1): 321–332.
- Laitano RF, Guerra AS, Pimpinella M, et al. Charge collection efficiency in ionization chambers exposed to electron beams with high dose per pulse. Phys Med Biol. 2006; 51(24): 6419–6436.
- Gunderson LL, Willett CG, Harrison LB, Calvo FA. Intraoperative Irradiation: Techniques and Results. Humana Press, Totowa 1999.
- Musielak M. The assessment of the effect of ionizing radiation dose and dose rate for breast cancer cells. Lett Oncol Sci. 2018; 19(4): 117–125.
- Joiner M. Quantifing cell kill and cell survival. In: Joiner M, Van der Kogel A. ed. Basic Clinical Radiobiology. Hodder Arnold, London 2009: 41–55.
- Medyczne urządzenia elektryczne. Część 2–1: Szczegółowe wymagania bezpieczeństwa akceleratorów elektronów w zakresie od 1 MeV do 50 MeV. PKN, Warszawa 2005.
- Medical electrical equipment — Medical electron accelerators — Functional performance characteristics. Geneva, IEC 60976.