Development of an ultrasmall C-band linear accelerator guide for a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head

Yuichiro Kamino, Sadao Miura, Masaki Kokubo, Ichiro Yamashita, Etsuro Hirai, Masahiro Hiraoka, Junzo Ishikawa

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)

Abstract

We are developing a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head. It is capable of pursuing irradiation and delivering irradiation precisely with the help of an agile moving x-ray head on the gimbals. Requirements for the accelerator guide were established, system design was developed, and detailed design was conducted. An accelerator guide was manufactured and basic beam performance and leakage radiation from the accelerator guide were evaluated at a low pulse repetition rate. The accelerator guide including the electron gun is 38 cm long and weighs about 10 kg. The length of the accelerating structure is 24.4 cm. The accelerating structure is a standing wave type and is composed of the axial-coupled injector section and the side-coupled acceleration cavity section. The injector section is composed of one prebuncher cavity, one buncher cavity, one side-coupled half cavity, and two axial coupling cavities. The acceleration cavity section is composed of eight side-coupled nose reentrant cavities and eight coupling cavities. The electron gun is a diode-type gun with a cerium hexaboride (CeB6) direct heating cathode. The accelerator guide can be operated without any magnetic focusing device. Output beam current was 75 mA with a transmission efficiency of 58%, and the average energy was 5.24 MeV. Beam energy was distributed from 4.95 to 5.6 MeV. The beam profile, measured 88 mm from the beam output hole on the axis of the accelerator guide, was 0.7 mm×0.9 mm full width at half maximum (FWHM) width. The beam loading line was 5.925 (MeV)- Ib (mA)×0.00808 (MeVmA), where Ib is output beam current. The maximum radiation leakage of the accelerator guide at 100 cm from the axis of the accelerator guide was calculated as 0.33 cGymin at the rated x-ray output of 500 cGymin from the measured value. This leakage requires no radiation shielding for the accelerator guide itself per IEC 60601-2-1.

Original languageEnglish
Pages (from-to)1797-1808
Number of pages12
JournalMedical Physics
Volume34
Issue number5
DOIs
Publication statusPublished - 2007
Externally publishedYes

Keywords

  • C-band
  • Gimbaled x-ray head
  • Image-guided radiotherapy
  • Linear accelerator

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

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