부산대학교 도서관

Purpose: The introduction of implanted gold seed fiducial markers for prostate cancer patients at the WP Holman Clinic, Hobart in November 2007 provided the opportunity to compare practice both with other centres and with the previous practice of the clinic. Methods: Images from the first 15 patients implanted with fiducial markers were analysed to ascertain the correlation between online match to fiducial markers and offline bony match. Random and systematic errors in both the matches and any changes in action level (using a clinical action level of 3 mm) between image pairs were determined. Results: The study demonstrated that the use of fiducial markers in this clinic is practicable and that the random and systematic error of both the bony anatomy and fiducial match were similar to that of other studies. The change in action level between the use of fiducial markers and bony anatomy was 46% for anterior/posterior images and 63% for lateral images. This indicates that a match to bony anatomy could result in an underdose of the treatment volume and inclusion of unintended normal tissue in the high dose irradiated region. Conclusion: This small study demonstrates that the introduction of fiducial markers for image matching should result in more accurate isocentre placement.