Experimental validatlon of peripheral dose distribution of electron beams for eclipse electron Monte Carlo algorithm

Acar H., ÇAĞLAR M., Altinok A. Y.

Journal of Radiotherapy in Practice, cilt.17, sa.3, ss.279-288, 2018 (Scopus) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 17 Sayı: 3
  • Basım Tarihi: 2018
  • Doi Numarası: 10.1017/s1460396917000784
  • Dergi Adı: Journal of Radiotherapy in Practice
  • Derginin Tarandığı İndeksler: Scopus
  • Sayfa Sayıları: ss.279-288
  • Anahtar Kelimeler: electron beams, eMC, GGPB.EBT3 film, peripheral dose distribution
  • İstanbul Medipol Üniversitesi Adresli: Evet

Özet

Aim The accuracy of two calculation algorithms of the Varian Eclipse treatment planning system (TPS), the electron Monte Carlo algorithm (eMC) and general Gaussian pencil beam algorithm (GGPB) for calculating peripheral dose distribution of electron beams was investigated.Methods Peripheral dose measurements were carried out for 6, 9, 12, 15, 18 and 22 MeV electron beams using parallel plate ionisation chamber and EBT3 film in the slab phantom. Measurements were performed for 6×6, 10×10 and 25×25 cm2 cone sizes at d max of each energy up to 20 cm beyond the field edges. The measured and TPS calculated data were compared.Results The TPS underestimated the out-of-field doses. The difference between measured and calculated doses increase with the cone size. For ionisation chamber measurement, the largest deviation between calculated and measured doses is <4·29% using the eMC, but can increase up to 8·72% of the distribution using GGPB. For film measurement, the minimum gamma analysis passing rates between measured and calculated dose distributions for all field sizes and energies used in this study were 91·2 and 74·7% for eMC and GGPB, respectively.