Naslov
Evaluation of dose distribution due to setup uncertainties for bilateral head and neck radiotherapy treatment planning

Autori
Bibić, Juraj ; Grego, Timor ; Buinac, Ana ; Barišić, Lovro ; Hršak, Hrvoje ; Kovačević, Nenad

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
6th Alpe-Adria Medical Physics Meeting : abstracts / - , 2014

Skup
Alpe-Adria Medical Physics Meeting (6 ; 2014)

Mjesto i datum
Budimpešta, Mađarska, 29.05.2014. - 31.05.2014

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
dose distribution; patient setup uncertainties; head and neck radiotherapy; organs at risk; Gaussian blurring

Sažetak
Daily variation of patient setup causes differences between planned and delivered patient radiotherapy treatment. Purpose of this work was to evaluate influence of random setup uncertainties to dose distribution for organs at risk (OAR). In this case OARs were parotid glands and medulla spinalis. In this work evaluation was made for 12 head and neck cancer patients. They were treated using ConPas (conformal parotid sparing) 3D conformal technique. Prescribed doses on bilateral PTV were 50 Gy. Most of the patients had boost that ranged between 60 and 70 Gy, but for present moment this is not included in the study. Contouring, planning and evaluation were made on XiO/Focal treatment planning system. Site specific random patient setup variations were determined and after determination of dose distribution matrices, setup variation was modelled by applying Gaussian blurring. Also, blurring was applied for hypothetical offsets of 2, 4 and 6 mm in all directions independently. Afterwards, data were analyzed, and changes in OAR doses were recorded. Measured random patient setup variation (sigma) was 2.4 mm in all directions which showed no significant dose increase to OARs. Hypothetical offset of 6 mm in left-right and anterior-posterior direction showed up to 5% of dose escalation to medulla spinalis. Mean doses to both parotid glands showed no significant deviations from original plan. Analysis of our model showed that patient setup variation of 2.4 mm in all directions should not have major influence to OARs related complications. Hypothetical offsets in all directions independently showed that increased attention should be made for left-right and anterior-posterior offsets.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kliničke medicinske znanosti

POVEZANOST RADA