Biomedical subjects

K Rykers

Publications and source records attributed to K Rykers.

3 recordsLinked to original sources

PubMed2004

An IMRT dose distribution study using commercial verification software.

The introduction of IMRT requires users to confirm that the isodose distributions and relative doses calculated by their planning system match the doses delivered by their linear accelerators. To this end the commercially available software, VeriSoft (PTW-Freiburg, Germany) was trialled to determine if the tools and functions it offered would be of benefit to this process. The CMS XiO (Computerized Medical System, St. Louis, MO) treatment planning system was used to generate IMRT plans that were delivered with an upgraded Elekta SL15 linac. Kodak EDR2 film sandwiched in RW3 solid water (PTW-Freiburg, Germany) was used to measure the IMRT fields delivered with 6 MV photons. The isodose and profiles measured with the film generally agreed to within +/- 3% or +/- 3 mm with the planned doses, in some regions (outside the field) the match fell to within +/- 5%. The isodose distributions of the planning system and the film could be compared on screen, allowing for electronic records of the comparison to be kept if desired. The features of this software would be of benefit to an IMRT QA program.

Benchmarking↗

PubMed1998

An alternative buildup material: combine dressing and liquid paraffin.

A tissue substitute of combine dressing (gauze and cottonwool) soaked with liquid paraffin was found to be a practical, easily manufactured and inexpensive buildup material for use in treating radiation therapy patients with electron and photon beams. Tissue equivalence was measured for electron energies of 6, 9, 12, and 16 MeV and photon energies of 6 MV and 10 MV delivered by a Varian 2100C linear accelerator. The solid water equivalence of the combine dressing/liquid paraffin material was approximately 1.2 times the geometric thickness of tissue substitute material across all energies.

Bandages↗

PubMed1995

Dynamic wedge factors for a comprehensive range of fields.

Assessing the methods available to model wedge factors as applied to dynamic wedges over a comprehensive range of field elongations is the primary intention of this paper. Wedge factors for dynamically produced wedges were investigated by a series of measurements for square and rectangular fields. A Varian 600C linear accelerator was used for the experimental work. Dynamic wedge angles of 15, 30, 45 and 60 degrees were studied. (The wedge factor was defined as the ratio of the central axis dose reading at 10 cm deep of the wedged field to the reading at 10 cm depth for the same sized open field). The possibility of improving dynamic wedge factors for elongated fields by modelling the rectangular field with the equivalent square (Worthley) and also by the square field of equal area (Arthur) methods was evaluated. Dynamic wedge factors were found to depend on the field size in the wedged direction dominantly. The influence of field elongation in the non-wedged axis was found to be negligible. The experiments indicate that the derivation of a dynamic wedge factor for use with rectangular fields is best based on a square field with a side equal to that in the wedged axis. The application of two square field models (Worthley and Arthur) for elongated fields was found to produce significantly worsened wedge factors for the majority of the fields considered.

Humans↗