Theoretical and experimental investigations of a newly developed intracavitary applicator system for the radiothermotherapy of gynaecological tumours

Abstract

This paper describes a new type of applicator system for the intracavitary radiothermotherapy of gynaecological tumours. Hyperthermia and radiation can be delivered by one and the same applicator. The hyperthermia is delivered by a modified capacitive heating technique (27.12 MHz) combined with cooling systems, the radiation by the numerically controlled oscillation of a gamma source on the inside of the main applicator, the RF gamma applicator (HDR afterloading technique). Isotherms and isodoses can be adapted to the anatomical-pathological situation. Interactions between the applicator system and the surrounding tissue were investigated in a theoretical model (FEM). Complex two-dimensional SAR calculations as well as three-dimensional temperature calculations were carried out. The RF gamma applicator was also examined by thermography; the thermography proved the theoretical modelling to be correct. The applicators were also tested in animal experiments.

Measurement of the thermal conductivity of polyacrylamide tissue-equivalent material

“…The composition of polyacrylamide-based materials, in particular, can be adjusted to mimic the electrical and thermal properties of various types of human tissue [1][2][3] . As a result, these materials have been used extensively to evaluate radiofrequency (RF) and microwave applicators for hyperthermia and thermal therapy [4][5][6][7][8][9][10][11][12][13][14][15][16] , to validate numerical simulations of RF and microwave-based hyperthermia treatments 13,[17][18][19] and to evaluate the use of various thermometry techniques in RF and microwave hyperthermia [20][21][22][23][24][25][26] .…”

Endocervical ultrasound applicator for integrated hyperthermia and HDR brachytherapy in the treatment of locally advanced cervical carcinoma

“…24,25 Endocavity devices for localized HT in the cervix have been developed based on radiofrequency or microwave sources, but these devices have limited thermal penetration or limited control over temperature distributions. [26][27][28] The objective of this work was to develop and characterize an endocervical ultrasound applicator for 3-D conformable HT delivery to the cervix adjunct to HDR brachytherapy. This device, shown in concept in Fig.…”