A machine vision system with CCD cameras for patient positioning in radiotherapy: a preliminary report.

Tadamasa Yoshitake, Katsumasa Nakamura, Yoshiyuki Shioyama, Tomonari Sasaki, Saiji Ohga, Toshihiro Yamaguchi, Takashi Toba, Shigeo Anai, Hiromi Terashima, Hiroshi Honda

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


PURPOSE: To determine positioning accuracy of a machine vision system in radiotherapy. MATERIALS AND METHODS: The machine vision system was composed of 640 x 480 pixel CCD cameras and computerized control systems. For image acquisition, the phantom was set up for the reference position and a single CCD camera was positioned 1.5 m from the isocenter. The image data of the fiducial marker with 1.5 mm lead pellet on the lateral surface of the phantom was captured onto the CCD, and then the position of the marker was accurately calculated. The phantom was moved 0.25, 0.50, 0.75, 1.00, 2.00, and 3.00 mm from the reference position, using a micrometer head. The position of the fiducial marker was analyzed using a kilo-voltage fluoroscopic imaging system and a machine vision system. RESULTS: Using fluoroscopic images, the discrepancy between the actual movement of the phantom by micrometer heads and the measurement was found to be 0.12 +/- 0.05 mm (mean +/- standard deviation). In contrast, the detection of the movement by the machine vision system coincided with the discrepancy of 0.0067 +/- 0.0048 mm. CONCLUSION: This study suggests that the machine vision system can be used to measure small changes in patient position with a resolution of less than 0.1 mm.

Original languageEnglish
Pages (from-to)399-405
Number of pages7
JournalFukuoka igaku zasshi = Hukuoka acta medica
Issue number12
Publication statusPublished - Dec 2005

All Science Journal Classification (ASJC) codes

  • General Medicine


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