Basic treatment planning parameters for a 90Sr / 90Y source train used in endovascular brachytherapy.
Working groups of the AAPM, DGMP, and ESTRO have published recommendations for endovascular brachytherapy, introducing concepts of relevant parameters for dose specification and treatment planning. However, the procedures for this treatment remain often mainly based on trial protocols and manufacturer instructions. Treatment planning requires the essential knowledge of the radial and longitudinal dose distribution, as well as information about geometrical uncertainties. The present study includes a whole data set for daily clinical practice using a commercially available device for endovascular brachytherapy (Novoste Betacath). The dose distribution around the 90Sr seed train was calculated with Monte-Carlo algorithms and verified by film dosimetry. The radial dose profile was determined starting from the surface of the delivery catheter Calculated dose profiles were in good agreement to measured values. The geometrical uncertainties were estimated with a retrospective analysis of 51 patient treatments. This shows the importance of using a safety margin of at least 10 mm between Intervention Length and Reference Isodose Length. Based on the longitudinal dose profile and the necessary safety margins, the maximum treatable intervention length is 25 mm and 45 mm for a 40 mm and 60 mm source train, respectively.
Kirisits
Christian
C
Department of Radiotherapy and Radiobiology, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna. Christian.Kirisits@akhwien.at
Berger
Daniel
D
Schmid
Rainer
R
Syeda
Bonni
B
Pokrajac
Boris
B
Glogar
Dietmar
D
Pötter
Richard
R
Georg
Dietmar
D
D000465:Algorithms; D001918:Brachytherapy / Q000379:methods*; D006801:Humans; D009010:Monte Carlo Method; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D013324:Strontium / Q000493:pharmacokinetics / Q000627:therapeutic use*; D014018:Tissue Distribution; D015019:Yttrium / Q000493:pharmacokinetics / Q000627:therapeutic use*
D015019:Yttrium; D013324:Strontium