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The neutron therapy facility at the Gershenson Radiation Oncology Center, Harper University Hospital in Detroit has been operational since September 1991. The d(48.5)+Be beam is produced in a gantry mounted superconducting cyclotron designed and built at the National Superconducting Cyclotron Laboratory (NSCL). Measurements were performed in order to obtain the physical characteristics of the neutron beam and to collect the data necessary for treatment planning. This included profiles of the dose distribution in a water phantom, relative output factors and the design of various beam modifiers, i.e. wedges and tissue compensators. The beam was calibrated in accordance with international protocol for fast neutron dosimetry. Dosimetry and radiobiology intercomparisons with three neutron therapy facilities were performed prior to clinical use. The radiation safety program was established in order to monitor and reduce the exposure levels of the personnel. The activation products were identified and the exposure in the treatment room was mapped. A comprehensive quality assurance (QA) program was developed to sustain safe and reliable operation of the unit at treatment standards comparable to those for conventional photon radiation. The program can be divided into three major parts: maintenance of the cyclotron and related hardware; QA of the neutron beam dosimetry and treatment delivery; safety and radiation protection. In addition the neutron beam is used in various non-clinical applications. Among these are the microdosimetric characterization of the beam, the effects of tissue heterogeneity on dose distribution, the development of boron neutron capture enhanced fast neutron therapy and variety of radiobiology experiments. [ABSTRACT FROM AUTHOR]

A multi-leaf collimator (MLC) has been designed for installation on the super-conducting cyclotron at the Gershenson Radiation Oncology Center. This MLC will replace the existing multi-rod collimator and the increased efficiency thus achieved should allow for a 50% increase in the number of patients treated. A study of the penumbra region of the neutron beam with focused and unfocused collimator leaves has been completed, together with activation measurements in steel and tungsten. Results of these studies were used to finalize the collimator leaf design. A steel collimator leaf with a 5 mm projection at the isocenter and a wedge shaped section has been chosen, to provide beam divergence in the direction perpendicular to the leaf motion. The leaf profile is "stepped" to prevent neutron leakage. The rationale for this leaf design is discussed. The overall design of the collimator system and the incorporation of a remote wedge-changing device will be presented. Each leaf is positioned using a stepping motor; the leaf position is independently confirmed using an optical system incorporating a coherent fiber optic and a CCD camera. The control system is being designed to allow for the implementation of intensity modulated neutron radiation therapy (IMNRT). [ABSTRACT FROM AUTHOR]

During the past three years the number of neutron therapy patients treated at the Gershenson Radiation Oncology Center has remained approximately constant. The facility is operating at maximum load, approximately 9500 fields per year. In the present paper, data for the clinical load and usage of the cyclotron, since it entered routine clinical operation March 1992 are presented, together with data on machine downtime for the period March 1993 — February 2001. Recent and ongoing cyclotron improvement projects are described, including redesign work on the ion source, the beryllium target, the cryogenic and vacuum systems. The major improvement project, however, is the construction of a computer controlled multileaf collimator (MLC) to replace the existing multirod collimator[l] (MRC), which has been in use since patient treatments started in September 1991. [ABSTRACT FROM AUTHOR]

An introduction to a series of article about the thermoregulatory aspects of performance is presented including one on the influence of a warm environment on endurance exercise performance, implications for the cardiovascular system of the need to dissipate body heat during exercise, and the role of skin temperature in the etiology of fatigue.

An abstract of the article "The influence of glucagon-like-peptide-1 receptor single nucleotide polymorphisms on gastric emptying rate in caucasian men- a pilot study" by A. Yau, J. McLaughlin, R.J. Maughan and company is presented.