title: Use of Monte Carlo computation in benchmarking radiotherapy treatment planning system algorithms.
abstract: Radiotherapy treatments are becoming more complex, often requiring the dose to be calculated in three dimensions and sometimes involving the application of non-coplanar beams. The ability of treatment planning systems to accurately calculate dose under a range of these and other irradiation conditions requires evaluation. Practical assessment of such arrangements can be problematical, especially when a heterogeneous medium is used. This work describes the use of Monte Carlo computation as a benchmarking tool to assess the dose distribution of external photon beam plans obtained in a simple heterogeneous phantom by several commercially available 3D and 2D treatment planning system algorithms. For comparison, practical measurements were undertaken using film dosimetry. The dose distributions were calculated for a variety of irradiation conditions designed to show the effects of surface obliquity, inhomogeneities and missing tissue above tangential beams. The results show maximum dose differences of 47% between some planning algorithms and film at a point 1 mm below a tangentially irradiated surface. Overall, the dose distribution obtained from film was most faithfully reproduced by the Monte Carlo N-Particle results illustrating the potential of Monte Carlo computation in evaluating treatment planning system algorithms.
authors.affiliation: Department of Medical Physics and Clinical Engineering, Singleton Hospital, Swansea NHS Trust, UK.
authors.forename: R D
authors.initials: RD
authors.lastname: Lewis
authors.forename: S J
authors.initials: SJ
authors.lastname: Ryde
authors.forename: A W
authors.initials: AW
authors.lastname: Seaby
authors.forename: D A
authors.initials: DA
authors.lastname: Hancock
authors.forename: C J
authors.initials: CJ
authors.lastname: Evans
mesh_terms: D000465:Algorithms; D001859:Bone Neoplasms / Q000532:radiotherapy; D001842:Bone and Bones / Q000528:radiation effects; D005373:Film Dosimetry / Q000379:methods; D006801:Humans; D008168:Lung / Q000528:radiation effects; D008175:Lung Neoplasms / Q000532:radiotherapy; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D017785:Photons; D011874:Radiometry / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*