Magnetic tracking for TomoTherapy systems: gradiometer based methods to filter eddy-current magnetic fields.

Purpose: TomoTherapy systems lack real-time, tumor tracking. A possible solution is to use electromagnetic markers; however, eddy-current magnetic fields generated in response to a magnetic source can be comparable to the signal, thus degrading the localization accuracy. Therefore, the tracking system must be designed to account for the eddy fields created along the inner bore conducting surfaces.

Radiation proctopathy in the treatment of prostate cancer.

Purpose: To compile and review data on radiation proctopathy in the treatment of prostate cancer with respect to epidemiology, clinical manifestations, pathogenesis, risk factors, and treatment.

Methods: Medical literature databases including PubMed and Medline were screened for pertinent reports, and critically analyzed for relevance in the scope of our purpose.

Results: Rectal toxicity as a complication of radiotherapy has received attention over the past decade, especially with the advent of dose-escalation in prostate cancer treatment.

Tolerance of endorectal balloon in 396 patients treated with intensity-modulated radiation therapy (IMRT) for prostate cancer.

Purpose: To report patient tolerance and acute anorectal toxicity of an endorectal balloon used for prostate immobilization during 35 daily fractions.

Materials And Methods: The records of 396 patients treated for prostate cancer from October 1997 to November 2001 were reviewed. Patients were treated with intensity modulated radiation therapy (IMRT).

Rectal wall sparing by dosimetric effect of rectal balloon used during intensity-modulated radiation therapy (IMRT) for prostate cancer.

The use of an air-filled rectal balloon has been shown to decrease prostate motion during prostate radiotherapy. However, the perturbation of radiation dose near the air-tissue interfaces has raised clinical concerns of underdosing the prostate gland. The aim of this study was to investigate the dosimetric effects of an air-filled rectal balloon on the rectal wall/mucosa and prostate gland.

Theoretical foundation for real-time prostate localization using an inductively coupled transmitter and a superconducting quantum interference device (SQUID) magnetometer system.

Real-time, 3D localization of the prostate for intensity-modulated radiotherapy can be accomplished with passively charged radio frequency transmitters and superconducting quantum interference device (SQUID) magnetometers. The overall system design consists of an external dipole antenna as a power source for charging a microchip implant transmitter and SQUID magnetometers for signal detection. An external dipole antenna charges an on-chip capacitor through inductive coupling in the near field region through a small implant inductor.

The evolution of quality assurance for intensity- modulated radiation therapy (IMRT): sequential tomotherapy.

Purpose: To identify the pertinent issues to be addressed in successfully implementing IMRT using sequential tomotherapy into clinical reality and presenting the maturation of quality assurance (QA) programs for both the delivery system and patient treatments that allow routine clinical use of the system.

Materials And Methods: Initially, a cubic phantom containing silver halide film was exposed to the entire treatment before patient treatment. The processed films were digitized with a laser densitometer and the dose distributions were compared with that generated by the planning system.

The use of rectal balloon during the delivery of intensity modulated radiotherapy (IMRT) for prostate cancer: more than just a prostate gland immobilization device?

Purpose: The purpose of this study was to investigate the role of a rectal balloon for prostate immobilization and rectal toxicity reduction in patients receiving dose-escalated intensity-modulated radiotherapy for prostate cancer.

Patients And Methods: Patients with localized prostate cancer who were undergoing intensity-modulated radiotherapy were treated in a prone position, immobilized with a customized Vac-Lok bag (MED-TEC, Orange City, IA). A rectal balloon with 100 cc of air was used to immobilize the prostate.

Clinical experience with intensity-modulated radiation therapy (IMRT) for prostate cancer with the use of rectal balloon for prostate immobilization.

The implementation of intensity-modulated radiation therapy (IMRT) is the result of advances in imaging, radiotherapy planning technologies, and computer-controlled linear accelerators. IMRT allows both conformal treatment of tumors and conformal avoidance of the surrounding normal structures. The first patient treated with Peacock IMRT at Baylor College of Medicine took place in March 1994.

Prostate immobilization using a rectal balloon.

We use a rectal balloon for prostate immobilization during intensity modulated radiotherapy (IMRT) prostate treatment. To improve the accuracy of our prostate planning target volume, we have measured prostate displacements using computed tomography (CT)-CT fusion on patients that previously received gold seed implants. The study consists of ten patients that were scanned twice per week during the course of IMRT treatment.