engleski

Clinical simulations of prostate radiotherapy using BOMAB-like phantoms: results for photons

In this work, water tank experiments were extended to a BOMAB-like phantom. This phantom is more clinically realistic than a water tank, as it is composed of body, legs, arms and head sections in the form of water tanks of circular or elliptical cross section. It is sufficiently realistic to allow the simulation of some clinical treatments. In the experiments to be described, four types of prostate treatment were simulated: (i) Volumetric Modulated arc therapy (VMAT, 6 MV). (ii) Tomotherapy (6 MV) (iii) IMRT (6MV and 18 MV) (iv) 5-field conformal RT (15 MV) and 4-field conformal RT (6 MV and 18 MV Doses were measured in the BOMAB phantom over an axial distance of approximately 50 cm, at positions along five pipes, one on the longitudinal axis of the phantom and the remaining four adjacent and parallel. TLD, OSL and RPL dosemeters were used and a comparision of dosemeters under the same irradiation conditions showed that dosemeters generally agreed to within 3% compared with ion chamber reference measurements. Other comparisons were possible with this data. They include a comparison of doses (beam profiles) in different positions in the BOMAB phantom, a comparison of different treatment modalities in the two contributing clinical centres (Pisa and Krakow) and a comparison of dose profiles resulting from the different treatment techniques and the corresponding doses calculated by the treatment planning systems used to generate the treatment plans. Finally, preliminary measurements of surface doses at selected points on the trunk of the BOMAB phantom were made using TLD and diode detectors. The aim of this work is to investigate the possible relationships between surface doses and underlying doses within the phantom and thus to explore potential practical ways in which organ and tissue doses may be estimated when full-scale simulation is not possible in the clinic.

out-of-field doses in radiation therapy; RPL; TLD; OSL dosemeters; IMRT; VMAT; tomotherapy

Rad je prezentiran na skupu Workshop: Dosimetry for Second Cancer Risk Estimation EURADOS Annual Meeting Vienna 2012.