RT Journal Article SR Electronic T1 The Helmet Sign: Physiologic Radioactive Accumulation After 131I Therapy—A Case Report JF Journal of Nuclear Medicine Technology JO J. Nucl. Med. Technol. FD Society of Nuclear Medicine SP 164 OP 165 VO 32 IS 3 A1 Lorraine Ash A1 Bohdan Bybel A1 Donald Neumann A1 Wendy Beebe YR 2004 UL http://tech.snmjournals.org/content/32/3/164.abstract AB After 131I radioablative treatment, a 51-y-old woman underwent whole-body 131I scanning, which revealed intense uptake along the periphery of the skull. The patient disclosed that she had not washed her hair because she had obtained a new hairstyle between the 131I treatment and the scan. The intense uptake along the periphery of the skull represented radioactive physiologic accumulation at the patient’s scalp.