title: 'Tongue-and-groove' effect in intensity modulated radiotherapy with static multileaf collimator fields.
abstract: The 'tongue-and-groove problem' in step-and-shoot delivery of intensity modulated radiotherapy is investigated. A 'tongue-and-groove' index (TGI) is introduced to quantify the 'tongue-and-groove' effect in step-and-shoot delivery. Four different types of leaf sequencing methods are compared. The sliding window method and the reducing level method use the same number of field segments to deliver the same intensity map, but the TGI is much less for the reducing level method. The leaf synchronization method of Van Santvoort and Heijmen fails in step-and-shoot delivery, but a new method inspired by the method of Van Santvoort and Heijmen is shown to eliminate 'tongue-and-groove' underdosage completely.
authors.affiliation: MPCS, Ryerson University, 350 Victoria Street, Toronto, Ontario, M5B 2K3, Canada.
authors.forename: W
authors.initials: W
authors.lastname: Que
authors.forename: J
authors.initials: J
authors.lastname: Kung
authors.forename: J
authors.initials: J
authors.lastname: Dai
mesh_terms: D000465:Algorithms; D009038:Motion; D011786:Quality Control; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D011881:Radiotherapy, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity