NUMERICAL-CALCULATIONS OF TEMPERATURE DISTRIBUTION RESULTING FROM INTRACAVITARY HEATING OF THE UTERUS

Objective To estimate, using numerical calculations, the depth of tiss ue damage in the uterus following balloon thermal endometrial destruct ion. Design A parameter, therapeutic depth, was defined. This was the maximum depth into the uterine myometrium, from the uterine cavity, at which a predefined temperature was reached after a certain time and w ith a constant intracavitary temperature. Setting Departments of radia tion physics and gynaecology at a university hospital. Results After 3 0 min of treatment with an intracavitary temperature of 75 degrees C, the maximum depth into the myometrium at which the tissue had been exp osed to a temperature of 55 degrees C, when blood flow was neglected, was 8.9 mm. Taking into account blood flow the depth was 3.4 mm, and i ncluding the pressure because of the balloon it was 5.6 mm. With the i nclusion of a local increase in blood flow because of elevated tissue temperature the depth was 4.4 mm. Finally, when damage to blood vessel s due to coagulation was also accounted for, the depth was 5.2 mm. The therapeutic depth decreased only slightly when the treatment time was shortened to 15 min. Conclusions Numerical calculations provide a bas is for estimation of the optimal intracavitary temperature and treatme nt time when performing thermal endometrial destruction by means of a balloon catheter.