Patient specific computer automated dosimetry calculations during therapy with 111In octreotide

The aim of this study was to calculate the absorbed dose of 22 patients that were diagnosed for neuroendocrine tumours in liver and had received therapeutic dose of ¹¹¹In octreotide. In-111 octreotide infusion, via intrahepatic catheterization is well established technique in our Institution in hepatocellular carcinoma and neuroendocrine tumours treatments. The patient specific dosimetry calculations, for this way of treatment, were based on anterior and posterior scintigraphy images that were acquired immediately after radiopharmaceutical infusion, through hepatic arterial port and at 24 and 48 hours post-infusion. Gamma - camera was calibrated in order to estimate source organ activity considering count rate, patient´s body diameter and source organ size. The results showed that the tumour absorbed dose ranged from 2.5 to 18.4 mGy/ MBq, depending on the lesion size. Patient specific dosimetry calculations helps the physician to optimize the planning of the treatment, avoid side effects to healthy tissue and assign administered dose to treatment results.