A novel extrapolation method using OSL detectors for very small field output factor measurement for stereotactic radiosurgery.

Appropriate methods for the determination of very small X-ray beam output factors are essential to ensure correct clinical outcomes for stereotactic radiosurgery. To date, substantial work has been performed in identifying and quantifying suitable dosimeters for relative output factor (ROF) measurements including recent IAEA published recommendations. In this work, we provide a novel method using optically stimulated luminescent dosimeters (OSLDs) with different effective sizes of the readout area to determine ROFs.

Skin and build up dose determination for a 2.5 MV medical linear accelerator imaging beam.

The 2.5 MV Imaging beam produced by a Varian TrueBeam linear accelerator produces a dose build up effect at the beam entrance similar to other high energy photon beams. The surface dose values were found to range from 39% of maximum dose at a 5 cm × 5 cm field size up to 69% of maximum at a 40 cm × 40 cm field.

Practical time considerations for optically stimulated luminescent dosimetry (OSLD) in total body irradiation.

Total body irradiation (TBI) treatments are used to treat the whole body in preparation for hematopoietic stem cell (or bone marrow) transplantation. Our standard clinical regimen is a 12 Gy in 6 fraction, bi-daily technique using 6 MV X-rays at an extended Source-to-Surface distance (SSD) of 300 cm. Utilizing these characteristics, the beam dose rate is reduced below 7 cGy/min as is standard for TBI treatment.

Solar ultraviolet radiation response of EBT2 Gafchromic, radiochromic film.

Measurement of solar ultraviolet (UV) radiation is an important aspect of dosimetry for the improved knowledge of UV exposure and its associated health related issues. EBT2 Gafchromic film has been designed by its manufacturers as an improved tool for ionizing radiation dosimetry. The film is stated as exhibiting a significant reduction in UV response.

Scanner uniformity improvements for radiochromic film analysis with matt reflectance backing.

A simple and reproducible method for increasing desktop scanner uniformity for the analysis of radiochromic films is presented. Scanner uniformity, especially in the non-scan direction, for transmission scanning is well known to be problematic for radiochromic film analysis and normally corrections need to be applied. These corrections are dependant on scanner coordinates and dose level applied which complicates dosimetry procedures.

Measuring solar UV radiation with EBT radiochromic film.

Ultraviolet radiation dosimetry has been performed with the use of a radiochromic film dosimeter called Gafchromic EBT for solar radiation exposure. The film changes from a clear colour to blue colour when exposed to ultraviolet radiation and results have shown that the colour change is reproducible within ±10% at 5 kJ m(-2) UV exposure under various conditions of solar radiation. Parameters tested included changes in season (summer versus winter exposure), time of day, as well as sky conditions such as cloudy skies versus clear skies.