Learn More
A greyscale-based fully automatic deformable image registration algorithm, originally known as the 'demons' algorithm, was implemented for CT image-guided radiotherapy. We accelerated the algorithm by introducing an 'active force' along with an adaptive force strength adjustment during the iterative process. These improvements led to a 40% speed improvement(More)
PURPOSE Daily prostate deformation hinders accurate calculation of dose, especially to intraprostatic targets. We implemented a three-dimensional deformable registration algorithm to aid dose tracking for targeted prostate radiotherapy. METHODS AND MATERIALS The algorithm registers two computed tomography (CT) scans by iteratively minimizing their(More)
PURPOSE To determine whether a 3-mm isotropic target margin adequately covers the prostate and seminal vesicles (SVs) during administration of an intensity-modulated radiation therapy (IMRT) treatment fraction, assuming that daily image-guided setup is performed just before each fraction. MATERIALS AND METHODS In-room computed tomographic (CT) scans were(More)
PURPOSE To retrospectively test the hypothesis that rectal distension on the planning computed tomography (CT) scan is associated with an increased risk of biochemical and local failure among patients irradiated for prostate carcinoma when a daily repositioning technique based on direct prostate-organ localization is not used. METHODS AND MATERIALS This(More)
PURPOSE To quantify the interfraction variability in prostate and seminal vesicle (SV) positions during a course of intensity-modulated radiotherapy (IMRT) using an integrated computed tomography (CT)-linear accelerator system and to assess the impact of rectal and bladder volume changes. METHODS AND MATERIALS We studied 15 patients who had undergone IMRT(More)
PURPOSE To propose and evaluate online adaptive radiation therapy (ART) using in-room computed tomography (CT) imaging that detects changes in the target position and shape of the prostate and seminal vesicles (SVs) and then automatically modifies the multileaf collimator (MLC) leaf pairs in a slice-by-slice fashion. METHODS AND MATERIALS For(More)
BACKGROUND This study analyzed the outcome of salvage radiotherapy for biochemical failure after radical prostatectomy (RP). By comparing the outcomes for patients who received RT alone and for those who received combined RT and hormonal therapy, we assessed the potential benefits of hormonal therapy. PATIENTS AND METHODS This cohort was comprised of 101(More)
Ultrasound is a noninvasive, relatively easy, rapid, and real-time imaging technique for organ targeting for radiotherapy. Its application has been developed to a greater extent in prostate cancer than in other sites in which it has been shown to improve the accuracy of daily treatment delivery. With the move toward dose escalation and the need to maximally(More)
PURPOSE To determine whether prostate-specific antigen (PSA) doubling time predicts clinical outcomes in patients with prostate cancer that has been treated with combined radiation and hormone therapy. METHODS AND MATERIALS We reviewed the medical records of 621 men with nonmetastatic prostate cancer treated with radiation therapy and hormone therapy(More)
PURPOSE To compare the fits of various normal tissue complication probability (NTCP) models to a common set of late rectal toxicity data, with the aim of identifying the best model for predicting late rectal injury after irradiation. METHODS AND MATERIALS Late toxicity data from 128 prostate cancer patients treated on protocol with three-dimensional(More)