Automatic registration of portal images and volumetric CT for patient positioning in radiation therapy.

The efficacy of radiation therapy treatment depends on the patient setup accuracy at each daily fraction. A significant problem is reproducing the patient position during treatment planning for every fraction of the treatment process. We propose and evaluate an intensity based automatic registration method using multiple portal images and the pre-treatment CT volume.

Analysis of interfraction and intrafraction variation during tangential breast irradiation with an electronic portal imaging device.

Purpose: To evaluate the daily setup variation and the anatomic movement of the heart and lungs during breast irradiation with tangential photon beams, as measured with an electronic portal imaging device.

Methods And Materials: Analysis of 1,709 portal images determined changes in the radiation field during a treatment course in 8 patients. Values obtained for every image included central lung distance (CLD) and area of lung and heart within the irradiated field.

Detection of oxidative stress induced by low- and high-linear energy transfer radiation in cultured human epithelial cells.

A standardized dichlorofluorescin (DCF) fluorometric assay capable of measuring radiation-induced oxidative stress was used to determine the effectiveness of protons and high-mass, high-atomic number (Z) and high-energy (HZE) particles to produce oxidative stress in vitro. Protons were found to be about equally as effective as X rays in the generation of oxidative stress in cultured cells. However, 56Fe-ion beams with energies of 1 GeV/nucleon and 5 GeV/nucleon were less effective than X rays or gamma rays in inducing dichlorofluorescin (DCFH) oxidation.

Dosimetry for an Sr90/Y90 source train used for intravascular radiation of a hemodialysis graft.

Objective: Vascular access for hemodialysis is often achieved with an arterial-venous graft (AVG). Brachytherapy is being explored for prevention of stenosis within these grafts. The objective was to develop treatment planning (TP) capability for dialysis implants.

Verification of prostate treatment setup using computed radiography for portal imaging.

A non-film-based system was used to obtain high quality portal film images. Digital portal images were obtained with a computed radiography (CR) system, in which the film is replaced with a photostimulable phosphor plate. Digital processing of portal images enhanced the display contrast using regional histogram equalization.