Purpose: Volumetric changes of cervical lymph nodes during radiotherapy (RT) should be evaluated with B-mode sonography. It was our intention to test whether ultrasound could be used for therapeutic monitoring.
Method: 30 lymph nodes of 20 patients were measured. All patients underwent radiotherapy of the cervical region. All lymph nodes were checked at first one day before RT, and then once a week.
Results: Concerning the volume change, examined lymph nodes showed great differences. Pretreatment volume ranged from 0.26 to 96.5 cm3, median 4.9. Time volume 50%, i.e. time until volume had decreased by 50%, was reached after 21 (+/-11) days. Mean volume reduction was 1.3 (+/-1.6)% each day. Big lymph nodes needed more time until time volume 50%. Time volume 50% itself correlated positively with the therapeutic outcome. Sonographic lymph node volumetry was useful in 85% of all the patients.
Conclusions: Sonographic lymph node volumetry is a simple and practical method. It can be used easily in clinical routine. Radiotherapist can often gain therapeutically relevant information. We describe the use of sonography for therapy monitoring during RT. This has so far been an unknown potential of the method. However, further evaluation is required.