Quantitative duplex and color Doppler ultrasound in the follow-up of beta-irradiated (106Ru/106Rh) choroidal melanomas. A prospective study.
The tumor response to radiotherapy depends highly on the local oxygen concentration, which is governed by the tumor's microcirculatory network. The aim of this prospective study was to quantitate the neovascular blood flow in human choroidal melanomas prior to 106Ru/106Rh irradiation and during a 1-year follow-up period. Pulsatile blood flow was elicited by means of duplex and color Doppler ultrasound in 54 of a total of 55 untreated melanomas with a mean peak systolic frequency of 1.0 kHz (range 0.3-2.7 kHz). The neovascular blood flow decreased significantly 4 and 6 months after beta-irradiation. No intrinsic tumor vascularity was detected 8 and 12 months after treatment. In 3 patients, a rising peak systolic frequency occurred following radiotherapy in advance of recurrent tumor growth. Results indicate that the noninvasive quantitation of neovascular blood flow in irradiated choroidal melanomas by pulsed Doppler ultrasound offers a new diagnostic modality for assessing tumor recurrence.