title: Complaint-adaptive power density optimization as a tool for HTP-guided steering in deep hyperthermia treatment of pelvic tumors.
abstract: For an efficient clinical use of HTP (hyperthermia treatment planning), optimization methods are needed. In this study, a complaint-adaptive PD (power density) optimization as a tool for HTP-guided steering in deep hyperthermia of pelvic tumors is developed and tested. PD distribution in patients is predicted using FE-models. Two goal functions, Opt1 and Opt2, are applied to optimize PD distributions. Optimization consists of three steps: initial optimization, adaptive optimization after a first complaint and increasing the weight of a region after recurring complaints. Opt1 initially considers only target PD whereas Opt2 also takes into account hot spots. After patient complaints though, both limit PD in a region. Opt1 and Opt2 are evaluated in a phantom test, using patient models and during hyperthermia treatment. The phantom test and a sensitivity study in ten patient models, show that HTP-guided steering is most effective in peripheral complaint regions. Clinical evaluation in two groups of five patients shows that time between complaints is longer using Opt2 (p = 0.007). However, this does not lead to significantly different temperatures (T50s of 40.3 (Opt1) versus 40.1 degrees C (Opt2) (p = 0.898)). HTP-guided steering is feasible in terms of PD reduction in complaint regions and in time consumption. Opt2 is preferable in future use, because of better complaint reduction and control.
authors.affiliation: Erasmus MC, Daniel den Hoed Cancer Center, Department of Radiation Oncology, hyperthermia unit, Rotterdam, The Netherlands. r.canters@erasmusmc.nl
authors.forename: R A M
authors.initials: RA
authors.lastname: Canters
authors.forename: M
authors.initials: M
authors.lastname: Franckena
authors.forename: J
authors.initials: J
authors.lastname: van der Zee
authors.forename: G C
authors.initials: GC
authors.lastname: Van Rhoon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D006979:Hyperthermia, Induced / Q000009:adverse effects / Q000379:methods*; D008875:Middle Aged; D008953:Models, Anatomic; D009010:Monte Carlo Method; D018482:Muscle, Skeletal / Q000503:physiopathology; D009367:Neoplasm Staging; D010146:Pain; D010386:Pelvic Neoplasms / Q000473:pathology / Q000628:therapy*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome