[Lymphocyte depletion after irradiation of the chest region dependent on irradiation technics]

In a prospective alternating study, the mediastinum of patients with bronchial carcinomas was preoperatively irradiated with 2000 cGy in ten fractions for an isodose of 80% by Co-60 stationary field or pendulum therapy. The leucocyte and lymphocyte blood count was determined every day. It was found out that the lymphocyte depression was significantly higher after pendulum therapy than after stationary field therapy. This is explained by the fact that the lymphocyte depression is caused rather by the irradiation of lymphocytes in the blood stream than by the irradiation of bone marrow.