DNA Topoisomerase IB as a Potential Ionizing Radiation Exposure and Dose Biomarker.

In radiation exposure scenarios where physical dosimetry is absent or inefficient, dose estimation must rely on biological markers. A reliable biomarker is of utmost importance in correlating biological system changes with radiation exposure. Human DNA topoisomerase ІB (topo І) is a ubiquitous nuclear enzyme, which is involved in essential cellular processes, including transcription, DNA replication and DNA repair, and is the target of anti-cancer drugs.

Improved determination of the position and activity of a radioactive point source inside a bulky medium using several detectors. The special case of a lung counter--a general view.

A method is described to locate a radioactive point source in a lung using a commercial array of lung detectors. The method takes advantage of the fact that modern commercial systems consist of several Ge detectors, each connected to a multi-channel analyzer, and the information from each detector can be analyzed separately. The system is calibrated with point sources placed in various locations in the lungs of a phantom.

Establishing schedules for repeated doses of strontium and for concurrent chemotherapy in hormone-resistant patients with prostate cancer: measurement of blood and urine strontium levels.

Strontium-89 (Sr-89) alone or with concurrent chemotherapy has a role in the treatment of patients with prostate cancer (PCP). The schedules for repeated doses of Sr-89 or for concurrent chemotherapy is undetermined. The objective of this study was to measure the effective half-life (Te) of Sr-89 using a detector available in a nuclear research facility.

Location-independent determination of the activity of a point source in absorbing media.

The unknown distribution of a radioactive material in a bulky volume will induce considerable inaccuracies in the determination of its activity due to the unknown geometry and absorption factors. The methods of using two detectors and of employing the full-energy peak to total ratio were investigated to evaluate parameters, which can be used to improve the accuracy of activity determination.

The validity of the virtual point detector concept for absorbing media.

The concept of representing the detector volume by a virtual point detector in order to facilitate efficiency evaluations was proposed in the past for non-absorbing media. The validity of the model was expanded also to absorbing media present between the detector and a point source in front of it. Empirical values were determined based on experiments with aluminum, copper, iron and lead.