title: Quality and comfort in head and neck hyperthermia: A redesign according to clinical experience and simulation studies.
abstract: OBJECTIVE
  Clinical phase III trials have shown the benefit of adding hyperthermia to radiotherapy and chemotherapy for head and neck cancer (H&N). The HYPERcollar, a functional prototype capable of applying hyperthermia to the entire H&N region was developed. Specific absorption rate-based hyperthermia treatment planning (HTP) is used to optimise HYPERcollar treatments. Hence, besides treatment quality, reproduction and reproducibility of the HTP are also pivotal. In the current work we analysed the impact of key parameters on treatment quality and completely redesigned the mechanical layout of the HYPERcollar for improved treatment quality and patient comfort.
  
  
  METHODS
  The requirements regarding patient position and the water bolus shape were quantified by simulation studies. The complete mechanical redesign was based on these requirements and non-modellable improvements were experimentally validated.
  
  
  RESULTS
  From simulation studies we imposed the required positioning accuracy to be within ±5 mm. Simulation studies also showed that the water bolus shape has an important impact on treatment quality. Solutions to meet the requirements were 1) a redesign of the applicator, 2) a redesign of the water bolus, and 3) a renewed positioning strategy. Experiments were used to demonstrate whether the solutions meet the requirements.
  
  
  CONCLUSIONS
  The HYPERcollar redesign improves water bolus shape, stability and skin contact. The renewed positioning strategy allows for positioning of the patient within the required precision of ±5 mm. By clinically introducing the new design, we aim at improving not only treatment quality and reproducibility, but also patient comfort and operator handling, which are all important for a better hyperthermia treatment quality.
authors.affiliation: a Department of Radiation Oncology , Erasmus MC Cancer Institute , Rotterdam , the Netherlands and.
authors.forename: Zef
authors.initials: Z
authors.lastname: Rijnen
authors.affiliation: a Department of Radiation Oncology , Erasmus MC Cancer Institute , Rotterdam , the Netherlands and.
authors.forename: Paolo
authors.initials: P
authors.lastname: Togni
authors.affiliation: a Department of Radiation Oncology , Erasmus MC Cancer Institute , Rotterdam , the Netherlands and.
authors.forename: Roel
authors.initials: R
authors.lastname: Roskam
authors.affiliation: b Department of Industrial Design, Faculty of Industrial Design Engineering , Delft University of Technology , the Netherlands.
authors.forename: Stefan G
authors.initials: SG
authors.lastname: van de Geer
authors.affiliation: b Department of Industrial Design, Faculty of Industrial Design Engineering , Delft University of Technology , the Netherlands.
authors.forename: Richard H M
authors.initials: RH
authors.lastname: Goossens
authors.affiliation: a Department of Radiation Oncology , Erasmus MC Cancer Institute , Rotterdam , the Netherlands and.
authors.forename: Margarethus M
authors.initials: MM
authors.lastname: Paulides
mesh_terms: D003198:Computer Simulation; D004867:Equipment Design; D006257:Head; D006801:Humans; D006979:Hyperthermia, Induced / Q000295:instrumentation*; D009333:Neck
keywords: Electromagnetism; heat transfer modelling; radiofrequency/microwave; treatment planning/treatment optimization