Regional hyperthermia applicator design using FDTD modelling

• Published in: Physics in medicine & biology Vol. 46; no. 7; pp. 1919 - 1935
• Main Authors: Kroeze, H, Kamer, J B Van de, Leeuw, A A C De, Lagendijk, J J W
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.07.2001; Institute of Physics
• Subjects: Biological and medical sciences; Female; Humans; Hyperthermia, Induced - instrumentation; Hyperthermia, Induced - methods; Induced hyperthermia. Cryotherapy; Male; Medical sciences; Miscellaneous; Models, Statistical; Pelvic Neoplasms - radiotherapy; Pelvic Neoplasms - therapy; Phantoms, Imaging; Prostatic Neoplasms - radiotherapy; Prostatic Neoplasms - therapy; Radiotherapy - instrumentation; Radiotherapy - methods; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Treatment with physical agents; Treatment. General aspects; Tumors; Uterine Cervical Neoplasms - radiotherapy; Uterine Cervical Neoplasms - therapy; Water; Performance evaluation; Human; Geometrical shape; Applicator; Pelvic cavity; Aqueous medium; Combined treatment; Thermotherapy; Malignant tumor; Radiofrequency; Radiotherapy; Induced hyperthermia
• ISSN: 0031-9155; 1361-6560
• DOI: 10.1088/0031-9155/46/7/313

Recently published results confirm the positive effect of regional hyperthermia combined with external radiotherapy on pelvic tumours. Several studies have been published on the improvement of RF annular array applicator systems with dipoles and a closed water bolus. This study investigates the performance of a next-generation applicator system for regional hyperthermia with a multi-ring annular array of antennas and an open water bolus. A cavity slot antenna is introduced to enhance the directivity and reduce mutual coupling between the antennas. Several design parameters, i.e. dimensions, number of antennas and operating frequency, have been evaluated using several patient models. Performance indices have been defined to evaluate the effect of parameter variation on the specific absorption rate (SAR) distribution. The performance of the new applicator type is compared with the Coaxial TEM. Operating frequency appears to be the main parameter with a positive influence on the performance. A SAR increase in tumour of 1.7 relative to the Coaxial TEM system can be obtained with a three-ring, six-antenna per ring cavity slot applicator operating at 150 MHz.