Biomedical subjects

H T Kohut

Publications and source records attributed to H T Kohut.

3 recordsLinked to original sources

PubMed1997

Using asymmetric jaws to junction with previously treated areas.

The feasibility of employing asymmetric jaws to match previously irradiated portals has been investigated. According to the isodose plot of one treatment planning system a near perfect match can be obtained by exactly matching the beam divergence of the initial port. However, another treatment planning system shows a cold junction. Films taken at 6 cm depth show a 6% cold spot when matching at the inferior border of the previously irradiated port and a 7% hot spot when matching at the superior border. As long as one is aware of the limitations of computer planning and collimator setting tolerance, junctioning with asymmetric jaws may still be preferred over the conventional method of gapping on the skin, because it avoids larger hot and cold spots below and above the matchpoint.

Computer Simulation↗

PubMed1997

Utilizing the digital couch position display of the simulator.

The digital display of the simulator couch position is an often under utilized accessory. This function can be very helpful in determining patient separation and posterior source-to-skin distance (SSD) and also in the setting up of abutting and preplanned ports. Examples are presented to show the practical application for routine simulations.

Humans↗

PubMed1996

Improved dose distribution in the brain by collimator rotation.

Because the head slopes both in the sagittal and lateral directions, the brain is one of the anatomical areas which could benefit by the use of 3-dimensional compensators. The fabrication of 3-dimensional compensators is an expensive and complex task, and as such, not widely used. A standard wedge is often employed to compensate for skull curvature when treating a partial brain area, with the heel of the wedge placed either superior or lateral. This usually results in areas of over- and under dosage in the planning target volume. However, by rotating the collimator 45 degrees while using a standard wedge, with the heel placed superior-lateral, the dose distribution can be significantly improved.

Brain↗