PURPOSE: To analyze two methods of image-guided radiotherapy (IGRT) for external beam radiotherapy of prostate cancer. METHODS AND MATERIALS: The prostate was localized by ultrasound (US) in lateral (left/right), vertical (anteroposterior), and longitudinal (superior/inferior) dimensions and then by fiducial seed marker (SM) kV X-ray. Assuming initial setup to skin marks as the origin, the mean suggested shifts (for all dimensions) were hypothesized to be similar and within 1 mm of the origin. The three-dimensional distance discrepancy between suggested SM and US shift points was calculated. We hypothesized a mean discrepancy >5 mm as clinically significant. RESULTS: From 40 patients, 1019 US/SM measurements were obtained. Lateral, vertical, and longitudinal dimensional comparisons reveal statistically significant differences in mean shifts (p < 0.0001 for all). US dimensional shifts reveal significantly greater variability. The US three-dimensional vector is greater and more variable than the SM vector (p < 0.0001). The mean US/SM three-dimensional distance discrepancy is 8.8 mm (significantly >5 mm, p < 0.0001). CONCLUSIONS: Ultrasound and SM methods suggest different shifts. US data reveal greater systematic/random error vs. SM data. The US data suggest larger PTV expansion margins (approximately 9 mm) are necessary for US IGRT vs. SM IGRT (approximately 3 mm). The hypotheses that US and SM methods suggest similar shifts and that the mean US/SM three-dimensional distance discrepancy is < or =5 mm are rejected.
PURPOSE: To analyze two methods of image-guided radiotherapy (IGRT) for external beam radiotherapy of prostate cancer. METHODS AND MATERIALS: The prostate was localized by ultrasound (US) in lateral (left/right), vertical (anteroposterior), and longitudinal (superior/inferior) dimensions and then by fiducial seed marker (SM) kV X-ray. Assuming initial setup to skin marks as the origin, the mean suggested shifts (for all dimensions) were hypothesized to be similar and within 1 mm of the origin. The three-dimensional distance discrepancy between suggested SM and US shift points was calculated. We hypothesized a mean discrepancy >5 mm as clinically significant. RESULTS: From 40 patients, 1019 US/SM measurements were obtained. Lateral, vertical, and longitudinal dimensional comparisons reveal statistically significant differences in mean shifts (p < 0.0001 for all). US dimensional shifts reveal significantly greater variability. The US three-dimensional vector is greater and more variable than the SM vector (p < 0.0001). The mean US/SM three-dimensional distance discrepancy is 8.8 mm (significantly >5 mm, p < 0.0001). CONCLUSIONS: Ultrasound and SM methods suggest different shifts. US data reveal greater systematic/random error vs. SM data. The US data suggest larger PTV expansion margins (approximately 9 mm) are necessary for US IGRT vs. SM IGRT (approximately 3 mm). The hypotheses that US and SM methods suggest similar shifts and that the mean US/SM three-dimensional distance discrepancy is < or =5 mm are rejected.
Authors: Charles W Scarantino; Bradley R Prestidge; Mitchel S Anscher; Carolyn R Ferree; William T Kearns; Robert D Black; Natasha G Bolick; Gloria P Beyer Journal: Int J Radiat Oncol Biol Phys Date: 2008-10-01 Impact factor: 7.038
Authors: Daniel R Simpson; Joshua D Lawson; Sameer K Nath; Brent S Rose; Arno J Mundt; Loren K Mell Journal: Cancer Date: 2010-08-15 Impact factor: 6.860
Authors: Clifton D Fuller; Todd J Scarbrough; Jan-Jakob Sonke; Coen R N Rasch; Mehee Choi; Joe Y Ting; Samuel J Wang; Niko Papanikolaou; David I Rosenthal Journal: Phys Med Biol Date: 2009-11-24 Impact factor: 3.609
Authors: Markus Bohrer; Peter Schröder; Grit Welzel; Hansjörg Wertz; Frank Lohr; Frederik Wenz; Sabine Kathrin Mai Journal: Strahlenther Onkol Date: 2008-12-24 Impact factor: 3.621