Predictors for chronic urinary toxicity after the treatment of prostate cancer with adaptive three-dimensional conformal radiotherapy: dose-volume analysis of a phase II dose-escalation study.

Purpose: To identify factors predictive for chronic urinary toxicity secondary to high-dose adaptive three-dimensional conformal radiation.

Methods And Materials: From 1999 to 2002, 331 consecutive patients with clinical Stage II-III prostate cancer were prospectively treated (median dose, 75.6 Gy).

The dose-volume relationship of small bowel irradiation and acute grade 3 diarrhea during chemoradiotherapy for rectal cancer.

Purpose: Previous work has found a highly significant relationship between the irradiated small-bowel volume and development of Grade 3 small-bowel toxicity in patients with rectal cancer. This study tested the previously defined parameters in a much larger group of patients.

Methods And Materials: A total of 96 consecutive patients receiving pelvic radiation therapy for rectal cancer had treatment planning computed tomographic scans with small-bowel contrast that allowed the small bowel to be outlined with calculation of a small-bowel dose-volume histogram for the initial intended pelvic treatment to 45 Gy.

Effect of the first day correction on systematic setup error reduction.

Treatment simulation is usually performed with a conventional simulator using kV X-rays or with a computed tomography (CT) simulator before the treatment course begins. The purpose is to verify patient setup under the same conditions as for treatment planning. Systematic (preparation) setup errors can be introduced by this process.

Geometric and dosimetric evaluations of an online image-guidance strategy for 3D-CRT of prostate cancer.

Purpose: To evaluate an online image-guidance strategy for conformal treatment of prostate cancer and to estimate margin-reduction benefits.

Methods And Materials: Twenty-eight patients with at least 16 helical computed tomography scans were each used in this study. Two prostate soft-tissue registration methods, including sagittal rotation, were evaluated.

Phase II dose escalation study of image-guided adaptive radiotherapy for prostate cancer: use of dose-volume constraints to achieve rectal isotoxicity.

Purpose: In our Phase II prostate cancer Adaptive Radiation Therapy (ART) study, the highest possible dose was selected on the basis of normal tissue tolerance constraints. We analyzed rectal toxicity rates in different dose levels and treatment groups to determine whether equivalent toxicity rates were achieved as hypothesized when the protocol was started.

Methods And Materials: From 1999 to 2002, 331 patients with clinical stage T1 to T3, node-negative prostate cancer were prospectively treated with three-dimensional conformal adaptive RT.

Dose-volume analysis of predictors for chronic rectal toxicity after treatment of prostate cancer with adaptive image-guided radiotherapy.

Purpose: We analyzed our experience treating localized prostate cancer with image-guided off-line correction with adaptive high-dose radiotherapy (ART) in our Phase II dose escalation study to identify factors predictive of chronic rectal toxicity.

Materials And Methods: From 1999-2002, 331 patients with clinical stage T1-T3N0M0 prostate cancer were prospectively treated in our Phase II 3D conformal dose escalation ART study to a median dose of 75.6 Gy (range, 63.

Computed tomography guided management of interfractional patient variation.

Interfractional patient variation occurs regularly and considerably during the radiotherapy course. Consequently, a generic but large planning target margin has to be applied when patient treatment plan design based on a single pre-treatment computed tomography scan is used to guide multifraction radiation treatment, which creates a major limiting factor for radiotherapy improvement. Planning target margins can be significantly reduced using multiple (or 4-dimensional) image feedback management in the routine treatment process.

Assessment of residual error for online cone-beam CT-guided treatment of prostate cancer patients.

Purpose: Kilovoltage cone-beam CT (CBCT) implemented on board a medical accelerator is available for image-guidance applications in our clinic. The objective of this work was to assess the magnitude and stability of the residual setup error associated with CBCT online-guided prostate cancer patient setup. Residual error pertains to the uncertainty in image registration, the limited mechanical accuracy, and the intrafraction motion during imaging and treatment.

Cone-beam-CT guided radiation therapy: A model for on-line application.

Background And Purpose: This paper presents efficient and generalized processes for the clinical application of on-line X-ray volumetric cone-beam CT imaging (XVI) to improve the accuracy of patient set-up in radiation therapy. XVI image-guided therapy is illustrated by application to two contrasting sites, intra-cranial radiosurgery and prostate radiation therapy, with very different characteristics regarding organ motion, treatment precision, and imaging conditions.

Patients And Methods: On-line set-up errors are determined in a two-step process.

A dose-escalation trial with the adaptive radiotherapy process as a delivery system in localized prostate cancer: analysis of chronic toxicity.

Purpose: To evaluate the validity of the chosen adaptive radiotherapy (ART) dose-volume constraints while testing the hypothesis that toxicity would not be greater at higher tumor dose levels.

Materials And Methods: In the ART dose escalation/selection trial, treatment was initiated with a generic planning target volume (PTV) formed as a 1-cm expansion of the clinical target volume (CTV). After the first week of therapy, the patient was replanned with a patient-specific PTV, constructed with CT and electronic portal images obtained in the first 4 days of treatment.