Feasibility Study on Whether Divergent Aperture can be Used on Proton Therapy Radiotherapy

LIU Chunbo; LIU Hongdong; HUO Wanli; PEI Xi

doi:10.11804/NuclPhysRev.35.03.321

Passive Scattering Proton Therapy (PSPT) is one of the main technologies for proton radiation therapy. The dose distribution in the patient deviates from the ideal state due to the edge scattering effect when the beam passes through the aperture. In this paper, TOPAS, a Monte Carlo software, was used to simulate the passive scattering treatment head. The influence of the edge scattering effect of the two aperture sets on the dose distribution was compared. The proton beam at 70, 110, 160, 200, 230 and 250 MeV was tested respectively. We found that the scattering effect of the conventional aperture is most obvious at 70 MeV, and the flatness and hetergeneity of the lateral dose curve at the inlet of 0.5 cm of the tank reach 4.63%, 108.05%, respectively. The dose shift caused by the edge scattering effect decreases with increasing water depth and disappears at the Bragg peak. After using the divergent aperture, the flatness and uniformity at 70 MeV are reduced to 1.28% and 101.31%, respectively, and the 100, 160, and 200 MeV proton beams are improved in different extents. For a proton beam with an energy close to 250 MeV, there is no advantage in the lateral dose curve of the divergent aperture. For all energy protons, the secondary neutrons are reduced with divergent aperture. The results show that the divergent aperture is effective for PSPT and this study provides data support for further application in clinical practice.

Feasibility Study on Whether Divergent Aperture can be Used on Proton Therapy Radiotherapy

School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China

Funds: National Natural Science Foundation of China (11375181); National Key R&D Program of China(2017YFC0107504)

Received Date: 2018-07-12

Rev Recd Date: 2018-09-14

Publish Date: 2018-09-20

Key words:

Abstract: Passive Scattering Proton Therapy (PSPT) is one of the main technologies for proton radiation therapy. The dose distribution in the patient deviates from the ideal state due to the edge scattering effect when the beam passes through the aperture. In this paper, TOPAS, a Monte Carlo software, was used to simulate the passive scattering treatment head. The influence of the edge scattering effect of the two aperture sets on the dose distribution was compared. The proton beam at 70, 110, 160, 200, 230 and 250 MeV was tested respectively. We found that the scattering effect of the conventional aperture is most obvious at 70 MeV, and the flatness and hetergeneity of the lateral dose curve at the inlet of 0.5 cm of the tank reach 4.63%, 108.05%, respectively. The dose shift caused by the edge scattering effect decreases with increasing water depth and disappears at the Bragg peak. After using the divergent aperture, the flatness and uniformity at 70 MeV are reduced to 1.28% and 101.31%, respectively, and the 100, 160, and 200 MeV proton beams are improved in different extents. For a proton beam with an energy close to 250 MeV, there is no advantage in the lateral dose curve of the divergent aperture. For all energy protons, the secondary neutrons are reduced with divergent aperture. The results show that the divergent aperture is effective for PSPT and this study provides data support for further application in clinical practice.

HTML

Reference (17)

[1]	PODGORSAK E B. Radiation Oncology Physics:A Handbook for Teachers and Students[M]. Vienna:International Atomic Energy Agency, 2005:170.
[2]	NEWHAUSER W D, ZHANG R. Physics in Medicine and Biology, 2015, 60(8):155.
[3]	TAYAMA R, FUJITA Y, TADOKORO M, et al. Nucl Instr Meth A, 2006, 564(1):532.
[4]	HAN S, CHO G, LEE S B. Nuclear Engineering and Technology, 2017, 49(4):801.
[5]	SLOPSEMA R L, KOOY H M. Phys Med Biol, 2006, 51(21):5441.
[6]	TADDEI P J, FONTENOT J D, ZHENG Y, et al. Physics in Medicine and Biology, 2008, 53(8):2131.
[7]	KASE Y, YAMASHITA H, SAKAMA M, et al. Physics in Medicine and Biology, 2015, 60(15):5833.
[8]	VIDAL M, MARIZI D L, SZYMANOWSKI H, et al. PPhysics in Medicine and Biology, 2016, 61(4):1532.
[9]	ZHAO T, CAI B, SUN B, et al. Journal of Applied Clinical Medical Physics, 2015, 16(5):367.
[10]	PAGANETTI H, JIANG H, LEE S Y, et al. Medical physics, 2004, 49(4):2107.
[11]	AKAGI T, KANEMATSU N,Takatani Y, et al. Physics in Medicine and Biology, 2006, 506(3):1919.
[12]	PERL J, SHIN J, SCHUMANN J, et al. Medical Physics, 2012, 39(11):6818.
[13]	OOZEER R, MAZAL A, ROSENWALD J C, et al. Medical Physics, 1997, 24(10):1599.
[14]	VAN L P, VAN'T V A A, ZELLE H D, et al. Physics in Medicine and Biology, 2001, 46(3):653.
[15]	TITT U, ZHENG Y, VASSILIEV O N, et al. Physics in Medicine and Biology, 2008, 53(2):487.
[16]	ZHENG Y, FONTENOT J, TADDEI P, et al. Physics in Medicine and Biology, 2008, 53(1):187.
[17]	PAGANETTI H. Proton Therapy Physics[M]. Boca Raton:CRC Press, 2012:46.

Feasibility Study on Whether Divergent Aperture can be Used on Proton Therapy Radiotherapy

doi: 10.11804/NuclPhysRev.35.03.321

Abstract

References

Proportional views

通讯作者: 陈斌, bchen63@163.com

Article Metrics

Proportional views