In order to make the body outline clearly in SPECT images, we devised a simple line source holder with the objectives to have a lightweight line source, to reduce the radiation exposure to the staff and to make the system readily available. This technique was applied to evaluate the localizing lesions in patients with radioiodine treatment of thyroid cancer. 131I-SPECT imaging with body outline was found to be effective in 86.7 percent (13/15) of the cases compared with planar imaging. Clinically, the results significantly helped in the discrimination between cervical lymph node metastasis and thyroid bed, and between mediastinal lymph node metastasis and bone metastasis. In the case of multiple lung metastasis demonstrating diffuse accumulation in the lung fields, 131I-SPECT imaging with body outline did not provide an increase in sensitivity compared with planar imaging. This method is easy to perform and it is considered to be useful for localization of abnormal accumulation, relative to the body outline.