Naslov
Radiotherapy out-of-field dosimetry: Clinical simulations of prostate radiotherapy using BOMAB-like phantoms

Autori
Miljanić, Saveta ; Bessieres, Igor ; Bordy, Jean-Marc ; D'Agostino, Emiliano ; d’Errico, Francesco ; di Fulvio, Angela ; Domingo, Carles ; Kabat, Damian ; Knežević, Željka ; Olko, Pawel ; Silari, Marco ; Stolarczyk, Liliana ; Tana, Luigi ; Harrison, Roger

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, pp prezentacija, znanstveni

Izvornik
Proceedings of the 8th International Workshop on Ionizing Radiation Monitoring / Takayoshi Yamamoto - Ōarai : Chiyoda Technol Corporation (CTC), 2013, 197-209

Skup
8th International Workshop on Ionizing Radiation Monitoring

Mjesto i datum
Ōarai, Japan, 01.12.2012. - 02.12.2012

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
Radiotherapy; out-of-field dosimetry; BOMAB phantom; TLD; RPL

Sažetak
The induction of cancers following radiotherapy (second cancer) has been known for many years although the estimation of the probability of radiation carcinogenesis is not straightforward. The overall cancer risk is influenced by the (usually non-uniform) dose to several radiosensitive organs distant from the radiotherapy target volume. Improvements in cancer treatment have increased survival times and thus increased incidence of second cancer may be expected in the future. In addition, increased whole body exposure may result from developments in radiotherapy such as intensity modulated radiotherapy (IMRT) and tomotherapy. Whatever the difficulties and uncertainties in risk estimation, its foundation indisputably lies in the knowledge of the absorbed dose to the irradiated organs. Thus the measurement of out-of-field doses is a crucial pre-requisite for risk estimation and is the subject of the EURADOS working group 9. Several dosemeters are suitable for photon and neutron dosimetry - thermoluminescence (TL), optically stimulated luminescence (OSL), radiophotoluminescence (RPL), track etch and bubble detectors. Dosemeters were calibrated in a reference clinical linac beam in a water tank at a reference facility at CEA LIST/LNE LNHB, Saclay. In this work, the measurements were extended to BOMAB-like phantoms (approximately simulating the human body, but composed of easily-reproducible geometric volumes). In the experiments to be described, the following prostate treatments were simulated: Volumetric Modulated arc therapy (VMAT, 6 MV), Tomotherapy (6 MV), IMRT (6MV and 18 MV), 5-field conformal RT (15 MV) and 4-field conformal RT (6 MV and 18 MV). For water tank irradiations it was concluded that all photon dosemeters used (TLD, OSL and RPL) can be used for out-of-field dosimetry. Comparison under the same irradiation conditions showed that these dosemeters generally agreed to within 3% compared with ion chamber reference measurements. Other comparisons 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. Comparison of out-of-field doses for different modalities in two RT centres shows that differences in out-of-field doses for the same PTV can be even a factor of 4. For sparing adjacent organs-at-risk the best results for IMRT were obtained. On the other hand the lowest out-of-field doses were for MLC therapy.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kliničke medicinske znanosti

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