Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
권호 표지
DOI QR코드

DOI QR Code

Investigating the effects of a range shifter on skin dose in proton therapy

  • Ming Wang (Chengdu University of Technology) ;
  • Lei Zhang (Chengdu University of Technology) ;
  • Jinxing Zheng (Institute of Plasma Physics, Chinese Academy of Sciences) ;
  • Guodong Li (Chengdu University of Technology) ;
  • Wei Dai (Chengdu University of Technology) ;
  • Lang Dong (Chengdu University of Technology)
  • Received : 2022.06.29
  • Accepted : 2022.09.15
  • Published : 2023.01.25
Download PDF
⟨ Previous Next ⟩

Abstract

Proton treatment may deliver a larger dose to a patient's skin than traditional photon therapy, especially when a range shifter (RS) is inserted in the beam path. This study investigated the effects of an RS on skin dose while considering RS with different thicknesses, airgaps and materials. First, the physical model of the scanning nozzle with RS was established in the TOol for PArticle Simulation (TOPAS) code, and the effects of the RS on the skin dose were studied. Second, the variations in the skin dose and isocenter beam size were examined by reducing the air gap. Finally, the effects of different RS materials, such as polymethylmethacrylate (PMMA), Lexan, polyethylene and polystyrene, on the skin dose were analysed. The results demonstrated that the current RS design had a negligible effect on the skin dose, whereas the RS significantly impacted the isocenter beam size. The skin dose was increased considerably when the RS was placed close to the phantom. Moreover, the magnitude of the increase was related to the thickness of the inserted RS. Meanwhile, the results also revealed that the secondary proton primarily contributed to the increased skin dose.

Keywords

Acknowledgement

The authors wish to thank all of the members of the SC200 design team. The National Natural Science Foundation of China (No. 12105030), and the Scientific Research Foundation of the Education Department of Sichuan Province, China, have all contributed to this research (No.2022NSFSC1185).

References

  1. H. Paganetti, T. Bortfeld, Springer, Berlin, Heidelberg, 2006, pp. 345-363. Proton therapy[M]//New technologies in radiation oncology.
  2. Y. Lee, K. Hwang, Skin thickness of Korean adults[J], Surgical and radiologic anatomy 24 (3) (2002) 183-189. https://doi.org/10.1007/s00276-002-0034-5
  3. ICRU Report No. 39, Determination of dose equivalents resulting from external radiation sources, International Commission on Radiation Units and Measurements (1985).
  4. J.J. Cuaron, C. Cheng, H. Joseph, et al., Dosimetric comparison of skin surface dose in patients undergoing proton and photon radiation therapy for breast cancer[J], International Journal of Radiation Oncology, Biology, Physics 90 (1) (2014) S914.
  5. C.A. Carlsson, G.A. Carlsson, Proton dosimetry with 185 MeV protons[J], Health physics 33 (5) (1977) 481-484.
  6. A. Kern, C. Baumer, K. Kroninger, et al., Determination of surface dose in pencil beam scanning proton therapy[J], Medical Physics 47 (5) (2020) 2277e2288.
  7. T. Pfuhl, F. Horst, C. Schuy, et al., Dose build-up effects induced by delta electrons and target fragments in proton Bragg curves-measurements and simulations[J], Physics in Medicine & Biology 63 (17) (2018), 175002.
  8. J. Shen, W. Liu, A. Anand, et al., Impact of range shifter material on proton pencil beam spot characteristics[J], Medical physics 42 (3) (2015) 1335-1340. https://doi.org/10.1118/1.4908208
  9. R. PIDIKITI, B.C. PATEL, M.R. MAYNARD, et al., Commissioning of the world's First compact pencil-beam scanning proton therapy system[J], Journal of applied clinical medical physics 19 (1) (2018) 94-105. https://doi.org/10.1002/acm2.12225
  10. Y.G.H. YU, Y. HU, et al., Study on the influence of the range shifter material in a scanning nozzle for proton therapy based on Monte Carlo method[C], 10th Int. Partile Accelerator Conf.(IPAC'19) (19-24 May 2019) 4100-4102.
  11. L. Kelleter, B. Zhen-Hong Tham, R. Saakyan, et al., Simulation of dose buildup in proton pencil beams[J], Medical Physics 46 (8) (2019) 3734-3738. https://doi.org/10.1002/mp.13660
  12. A. Kern, C. Baumer, K. Kr € oninger, et al., Impact of air gap, range shifter, and € delivery technique on skin dose in proton therapy[J], Medical Physics 48 (2) (2021) 831-840. https://doi.org/10.1002/mp.14626
  13. J. Perl, J. Shin, J. Schumann, et al., TOPAS: an innovative proton Monte Carlo platform for research and clinical applications[J], Medical physics 39 (11) (2012) 6818-6837. https://doi.org/10.1118/1.4758060
  14. M. Wang, J. Zheng, Y. Song, et al., Monte Carlo simulation using TOPAS for gas chamber design of PBS nozzle in superconducting proton therapy facility[J], Nuclear Technology 206 (5) (2020) 779-790. https://doi.org/10.1080/00295450.2019.1670011
  15. A.D. Wrixon, New recommendations from the international commission on radiological protection-a review[J], Physics in Medicine & Biology 53 (8) (2008) R41.
  16. M.J. Butson, J.N. Mathur, P.E. Metcalfe, Skin dose from radiotherapy X-ray beams: the influence of energy[J], Australasian radiology 41 (2) (1997) 148-150. https://doi.org/10.1111/j.1440-1673.1997.tb00615.x
  17. B. Nilsson, B. Sorcini, Surface dose measurements in clinical photon beams[J], Acta Oncologica 28 (4) (1989) 537-542. https://doi.org/10.3109/02841868909092265
  18. P. Rapley, Surface dose measurement using TLD powder extrapolation[J], Medical Dosimetry 31 (3) (2006) 209-215. https://doi.org/10.1016/j.meddos.2006.02.003
  19. N. Dogan, G.P. Glasgow, Surface and build-up region dosimetry for obliquely incident intensity modulated radiotherapy 6 MV x rays[J], Medical Physics 30 (12) (2003) 3091-3096. https://doi.org/10.1118/1.1625116
  20. S.F. Kry, S.A. Smith, R. Weathers, et al., Skin dose during radiotherapy: a summary and general estimation technique[J], Journal of applied clinical medical physics 13 (3) (2012) 20-34.
  21. C.Z. Jarlskog, H. Paganetti, Physics settings for using the Geant4 toolkit in proton therapy[J], IEEE Transactions on nuclear science 55 (3) (2008) 1018-1025. https://doi.org/10.1109/TNS.2008.922816