Aim: This work is engaged with the volume change of neck lymph node metastasis of malignant tumors in the head-neck region during radiotherapy.
Patients and method: In 54 patients with head and neck tumors, the volume of neck lymph nodes before and after radiation was measured. The volumetry was done with CT planimetry. The total dose was 66 Gy (2 Gy/d) telecobalt from 2 lateral opponated fields. The time of volume change could be defined with measuring of the half-time and the doubling-time by the help of Schwartz formula.
Results: After 10 Gy the volume diminution was about 20% and half-time 24 to 26 days. Afterwards the time of volume diminution picked up speed and finally achieved 60 to 72%. Meanwhile the half-time decreased to the half value. The result was independent of the site of primary tumor, the patient's sex and age.
Conclusion: In our opinion the effectivity of radiotherapy can best be judged with defining of the volume change of lymph nodes of the neck.