Technology in cancer research & treatment
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Technol. Cancer Res. Treat. · Aug 2008
Comparative StudyComparison of daily couch shifts using MVCT (TomoTherapy) and B-mode ultrasound (BAT System) during prostate radiotherapy.
The purpose of this study was to compare daily couch shifts after prostate localization between megavoltage CT (MVCT, Hi-ART TomoTherapy) and b-mode ultrasound (BAT system). Nine hundred and thirteen couch shifts from 22 consecutive patients treated using MVCT localization were compared to 853 shifts from 23 randomly selected patients treated using b-mode ultrasound prostate localization. Shifts were made in three principal axes based on prostate position after comparing daily images to the initial planning CT. ⋯ When compared to MVCT, the use of BAT for prostate localization results in greater variability of positional adjustments in vertical and CC directions. This likely reflects differences in the ability to precisely align b-mode ultrasound contours to KVCT images, as well as prostate excursion in vertical and CC direction caused by the ultrasound probe. These considerations need to be made when defining treatment volumes, and argue for the use of less disruptive techniques for daily prostate localization.