Increased serum amylase in patients after radiotherapy as a probable bioindicator for radiation exposure.

The radiation-induced increase of serum amylase is investigated in 41 patients following either whole body irradiation or irradiation of the head- and neck-region. The radiation treatment caused a dose-independent serum amylase increase up to 80 times of the preirradiation measured in controls. This increase can only be induced if the salivary glands are within the radiation field. An isoenzyme analysis differentiated between salivary and pancreatic amylase. It was shown that also in case of whole body irradiation pancreatic proteins either contribute only to a small extent to the increase or show no recognizable change. Although great variations in radiation response remain, the increase of serum amylase produced by salivary glands is highly significant and serves as a bioindicator for radiation exposures.