- © 2007 by the American Society of Radiologic Technologists
Iodine 131 Uptake Related to Hair Dyeing
- Art Meyers, Ed.D., R.T.(N), CNMT,
- Lakeisha Harry, B.S., R.T.(N), CNMT and
- Brigitte Peterson
One of the more common radionuclide therapies performed by nuclear medicine departments involves administering iodine 131 for thyroid ablation in the treatment of thyroid cancer. Therapeutic doses of 131I are administered in liquid or capsule form, with the liquid form requiring greater care in handling. Federal regulations specifically address safety requirements in working with patients who have received 131I, and the Nuclear Regulatory Commission and individual states, such as Nevada, have outlined conditions for patient release.1
The specificity of 131I whole-body imaging for detecting residual or recurrent local or metastatic disease generally is reported to be greater than 90%.2 However, false-positive findings in 131I whole-body imaging have been well documented. These false-positive findings are illustrated by the following case study in which physiologic accumulation from perspiration presumably caused contamination artifacts and physiologic variants.3
Case Study
A 31-year-old female patient with papillary thyroid carcinoma underwent surgical resection and radionuclide therapy. Two years later, 3 nodes on the right side of her neck were identified. The patient’s thyroid globulin level was 77, and her thyroid stimulating hormone level was 88, which is consistent with residual thyroid disease or recurrence. Her thyroid globulin level 1 year ago was only 2.
Because of the significant thyroid globulin increase, a whole-body 131I scan was ordered to identify any residual disease. The patient received 205 mCi (7688 MBq), administered orally in capsule form. She returned 10 days later for the scan. Upon questioning, the patient revealed that between 131I administration and the first scan she had dyed her hair.
The images revealed no lung or bone uptake. Some activity was seen in the salivary glands and nasal region, and there was a fair amount of activity in the scalp, particularly the posterior scalp. (See Fig. 1⇓.) Activity also was seen above the patient’s upper lip, as well as on her hands and feet.
Whole-body 131I scan showing activity in the scalp, above the upper lip and on the hands and feet.
The patient had a rather thick head of hair, and the scalp uptake most likely represented residual 131I excreted by sweating through the scalp. The activity on the hands and feet might have resulted from the hair dyeing process and subsequent showering (ie, standing in water that collected on the shower floor before draining). It is not known whether the patient applied the coloring product to her upper lip, but this could account for the uptake in that area. No evidence of metastatic disease was seen on these images, but the markedly increased thyroid globulin level indicates that the patient did have some type of recurrence.
There are many documented cases of false-positive findings after radionuclide 131I treatment. Many of these findings are primarily physiologic in nature, such as sweating on the scalp.2 Contamination of personal items, such as perspiration on jewelry or nasal secretions on a handkerchief, is reported less often but represents a pitfall for accurate interpretation of 131I whole-body scans.4 In this case study, hair dyeing and subsequent trapping of perspiration under the hair appear to have resulted in an increase in tracer uptake.
Footnotes
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Art Meyers, Ed.D., R.T.(N), CNMT, is an associate professor in the nuclear medicine program at the University of Nevada, Las Vegas. Lakeisha Harry, B.S., R.T.(N), CNMT, is chief technologist in the nuclear medicine department at Valley Hospital in Las Vegas. Brigitte Peterson is a student in the nuclear medicine program at UNLV.
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The authors wish to thank Dean Easton, M.D., for his diagnostic interpretation of this study.
