Biomedical subjects

M M Bilek

Publications and source records attributed to M M Bilek.

3 recordsLinked to original sources

PubMed2005

Real-time verification of HDR brachytherapy source location: implementation of detector redundancy.

Independent treatment verification for high dose rate (HDR) brachytherapy is needed to ensure that the treatment proceeds as prescribed. In this paper, we investigate the feasibility of a proposed real-time source position verification process. This process provides immediate confirmation of the source position during the treatment, so that the treatment can be aborted and modified if necessary. We show that an array of dosimeters placed on the patient's skin can independently verify the position in three dimensions. This verification was demonstrated by using a diamond detector placed in several locations on the surface of an anthropomorphic phantom. A mathematical algorithm was constructed to estimate the location of the source given a measured data set in the presence of tissue heterogeneity. The accuracy of the source localization was found to increase with the number of detectors used to compute the estimation of the source position. The resolution to which the 12 detectors can identify the location of the source was within 3 mm.

Algorithms↗

PubMed2003

Apparatus for exposing cell membranes to rapid temperature transients.

We seek to determine whether cell membranes contain sensors that trigger a downstream response to temperature excursions. To do this, we have developed a novel apparatus for exposing a cell membrane to an extremely rapid temperature excursion in the nanosecond range. Cells are plated on a gold surface that is back-heated by a pulsed laser and cooled by conduction of heat into the glass substrate and the liquid medium. Analysis using the heat diffusion equation shows that the greatest temperature rise is localized within a region tens of nanometres thick, suitable for specifically heating a cell membrane without heating the remainder of a cell. We refer to this device as a nanosecond hotplate.

Cell Culture Techniques↗

PubMed2003

High dose-rate brachytherapy source localization: positional resolution using a diamond detector.

A potential real-time source position verification process for high dose-rate (HDR) brachytherapy treatment is described. This process is intended to provide immediate confirmation that a treatment is proceeding according to plan, so that corrective action can be taken if necessary. We show that three dosimeters are in principle sufficient and demonstrate the feasibility of the process using a diamond detector and an Ir-192 source. An error analysis including all identified sources of error shows that this detector is capable of locating the distance to the source to within 2 mm for distances up to 12 cm. This positional accuracy is less than the diameter of typical HDR catheters indicating that a diamond detector can be used to accurately determine the distance to the source. The uncertainty in the distance is found to increase with distance.

Algorithms↗