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Li Y, Liu H, Huang N, Wang Z, Zhang C. The Measurement of the Surface Dose in Regular and Small Radiation Therapy Fields Using Cherenkov Imaging. Technol Cancer Res Treat 2022; 21:15330338211073432. [PMID: 35119327 PMCID: PMC8819764 DOI: 10.1177/15330338211073432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Purpose: The aim of this study is to measure the output factor (OF)
and profile of surface dose in regular and small radiation therapy fields using
Cherenkov imaging (CI). Methods: A medical linear accelerator
(linac) was employed to generate radiation fields, including regular open photon
field (ROPF), regular wedge photon field (RWPF), regular electron field (REF)
and small photon field (SPF). The photon beams consisted of two filter modes
including flattening filter (FF) and flattening filter free (FFF). All fields
were delivered to a solid water phantom. Cherenkov light was captured using a
charge-coupled device system during phantom irradiation. The OF and profile of
surface dose measured by CI were compared with those determined by film
measurement, ionization chamber measurement and treatment planning system
calculation in order to examine the feasibility of measuring surface dose OF and
profile using CI. Results: The discrepancy between surface dose OF
measured by CI and that determined by other methods is less than 6% in ROPFs
with size less than 10 × 10 cm2, REFs with size less than 10 × 10
cm2, and SPFs except for 1 × 1 cm2 field. In the flat
profile region, the discrepancy between surface dose profile measured by CI and
that determined by other methods is less than 4% in REFs and less than 3% in
ROPFs, RWPFs, and SPFs except for 1 × 1 cm2 field. The discrepancy of the
surface dose profile is in compliance with the recommendation by IAEA TRS 430
reports. The discrepancy between field width measured by CI and that determined
by film measurement is equal to or less than 2 mm, which is within the tolerance
recommend by the guidelines of linac quality assurance in regular open FF photon
fields, SPFs, and REFs with cone size of 10 × 10 cm2 in area.
Conclusion: CI can be used to quantitatively measure the OF and
profile of surface dose. It is feasible to use CI to measure the surface dose
profile and field width in regular open FF photon fields and SPFs except for
1 × 1 cm2 field.
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Affiliation(s)
- Yi Li
- State Key Laboratory of Transient Optics and Photonics, Xi’an
Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an
710119, China
- School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
- University of Chinese Academy of Sciences, Beijing 100049,
China
| | - HongJun Liu
- State Key Laboratory of Transient Optics and Photonics, Xi’an
Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an
710119, China
- Collaborative Innovation Center of Extreme Optics, Shanxi
University, Taiyuan 030006, China
- Hongjun Liu, PhD, State Key Laboratory of
Transient Optics and Photonics, Xi’an Institute of Optics and Precision
Mechanics, Chinese Academy of Sciences, Xi’an 710119, China.
Chunmin Zhang, PhD, School of Physics,
Xi’an Jiaotong University, Xi’an 710049, China.
| | - Nan Huang
- State Key Laboratory of Transient Optics and Photonics, Xi’an
Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an
710119, China
| | - Zhaolu Wang
- State Key Laboratory of Transient Optics and Photonics, Xi’an
Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an
710119, China
| | - Chunmin Zhang
- School of Physics, Xi’an Jiaotong University, Xi’an 710049, China
- Hongjun Liu, PhD, State Key Laboratory of
Transient Optics and Photonics, Xi’an Institute of Optics and Precision
Mechanics, Chinese Academy of Sciences, Xi’an 710119, China.
Chunmin Zhang, PhD, School of Physics,
Xi’an Jiaotong University, Xi’an 710049, China.
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