Multinodular goitre. Coloured Gamma Scan of a goitre of the thyroid gland, in front view. The thyroid is an endocrine gland in the neck and consists of two lobes (as seen). Multinodular goitre has here affected mainly the lobe at right swelling it to double its size. Nodules or lumps are seen; higher metabolic activity (red) occurs in the unaffected lobe. Goitre results in swelling of the neck, with symptoms such as weight loss, tremor and insomnia. Causes of goitre include Graves' disease, lack of dietary iodine, or a tumour. Gamma scanning involves injecting a radio- active tracer into the blood which is absorbed by the thyroid gland and detected by a gamma camera.