Real-time Doppler ultrasound to identify vessels and guide needle placement for gynecologic interstitial brachytherapy.

PURPOSE

Doppler ultrasound (US) gives real-time information regarding anatomy and blood vessel location to guide needle placement for gynecologic interstitial (IS) brachytherapy (BT). We retrospectively assessed Doppler US images for vessel quantity, size, and distribution in cervical cancer patients undergoing high-dose-rate BT at our institution.

METHODS AND MATERIALS

Eleven consecutive patients undergoing IS high-dose-rate BT implants for cervical cancer between 2015 and 2017 were included. Transrectal Doppler US was used for real-time image guidance. US images were retrospectively evaluated. Vessel quantity, size, and distribution at superior and inferior levels of the cervix were recorded. Correlation of vessel quantity with tumor size and International Federation of Gynecology and Obstetrics stage was evaluated.

RESULTS

Average vessel quantity was 4.2 in the inferior cervix and 3.8 in the superior cervix (range 1-11). Median vessel diameter was 2 mm in the inferior cervix and 2 mm in the superior cervix (range 1-6 mm). The most common location was posterolateral (3:00-5:00 and 7:00-9:00), outer third (78% of vessels inferiorly, 64% of vessels superiorly). Vessel quantity was correlated to initial tumor size superiorly (p = 0.04, paired t-test) but not inferiorly (p = 0.31, paired t-test). There was no correlation between vessel quantity and International Federation of Gynecology and Obstetrics stage (p > 0.05, analysis of variance). Doppler US was successfully used to guide needle placement away from visualized blood vessels with no incidents of hemorrhage in these patients.

CONCLUSIONS

Doppler US is a useful tool to guide needle placement for IS BT for cervical cancer. Vessel quantity varied with increased vessel quantity seen higher in the cervix for larger tumors. Vessels were most commonly distributed in the outer third of the posterolateral cervix.