HYPERTHERMIA TREATMENT PLANNING AND TEMPERATURE DISTRIBUTION RECONSTRUCTION - A CASE-STUDY

While a great deal of effort has been applied toward solving the techn ical problems associated with modelling clinical hyperthermia treatmen ts, much of that effort has focused on only estimating the power depos ition. Little effort has been applied toward using the modelled power depositions (either electromagnetic (EM) pr ultrasonic) as inputs to e stimate the hyperthermia induced three-dimensional temperature distrib utions. This paper presents a case report of a patient treated with hy perthermia at the Duke University Medical Center where numerical model ling of the EM power deposition was used to prospectively plan the tre atment. Additionally, the modelled power was used as input to retrospe ctively reconstruct the transient three-dimensional temperature distri bution. The modelled power deposition indicated the existence of an un desirable region of high power in the normal tissue. Based upon this r esult, amplitudes and phases for driving the hyperthermia applicator w ere determined that eliminated the region of high power and subsequent measurements confirmed this. The steady-state and transient three-dim ensional temperature distributions were reconstructed for four out of the seven treatments. The reconstructed Steady-state temperatures agre ed with the measured temperatures; root-mean-square error ranged from 0.45 to 1.21 degrees C. The transient three-dimensional tumour tempera ture was estimated assuming that the perfusion was constant throughout the treatment. Using the computed three-dimensional transient tempera ture distribution, the hyperthermia thermal dose was computed. The equ ivalent minutes at 43 degrees C achieved by 50% (T(50)Eq43) of the tum our volume was computed from the measured data and the three-dimension al reconstructed distribution yielding T(50)Eq43 = 40.6 and 19.8 min r espectively.