Improving hyperthermia treatment planning for the pelvis by accurate fluid modeling. Issue 10 (13th September 2016)

• Record Type: Journal Article
• Authors: Schooneveldt, G.; Kok, H. P.; Balidemaj, E.; Geijsen, E. D.; van Ommen, F.; Sijbrands, J.; Bakker, A.; de la Rosette, J. J. M. C. H.; Hulshof, M. C. C. M.; de Reijke, T. M.; Crezee, J.
• Is Part Of: Medical physics. Volume 43:Issue 10(2016)
• Page Start: 5442
• Page End: 5452
• Publication Date: 2016-09-13
• Subjects: bioelectric phenomena -- biological organs -- cancer -- convection -- dielectric properties -- flow simulation -- gels -- hyperthermia -- muscle -- phantoms -- tumours; Therapeutic applications, including brachytherapy -- Cancer -- Thermal convection -- Gels and sols -- Muscles -- Biothermics and thermal processes in biology; Radiation therapy; hyperthermia -- treatment planning -- bladder cancer -- fluid modeling; Medical treatment planning -- Convection -- Electrical conductivity -- Temperature measurement -- Fluid equations -- Muscles -- Dielectric properties -- Tissues -- Cancer -- Experiment design; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4961741
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: Hyperthermia is an established (neo)adjuvant treatment modality for a number of pelvic malignancies. Optimal treatment of these tumors requires robust treatment planning, but up until now, the urinary bladder was not modeled accurately, making current simulations less reliable. The authors improved the dielectric and thermophysical model of the urinary bladder in their treatment planning system, and showed the improvements using phantom experiments. Methods: The authors suspended a porcine bladder in muscle tissue equivalent gel and filled it with 120 ml 0.9% saline. The authors heated the phantom during 15 min with their deep hyperthermia device, using clinical settings, and measured the temperature both inside and outside the bladder. The authors simulated the experiment, both using the clinically used treatment planning system, and using the improved model featuring correct dielectric properties for the bladder content and an enhanced thermophysical model, enabling the simulation of convection. Results: Although the dielectric changes have an impact throughout the phantom, the dominant effect is a higher net heat absorption in the bladder. The effects of changing the thermophysical model are limited to the bladder and its surroundings, but result in a very different temperature profile. The temperatures predicted by the simulations using the new bladder model were in much better agreement with the measurements than those predicted by currently used treatment planning system. Conclusions: Modeling convection in the urinary bladder is very important for accurate hyperthermia treatment planning in the pelvic area.