The effects of a custom-made lead collar on dose rates of patients treated with 131I.

We studied the effects of a custom-made lead collar on dose rates and hospitalization days of patients treated with high doses (>400 MBq) of radioiodine (131I). Between October 2005 and March 2006, the dose rates of 28 consecutive patients were studied. Dose rates of patients with and without the collar (5.5 mm lead) were measured daily until the rate dropped below the discharge dose rate of 20 microSv-1 h at 1 m. Age, sex, 131I dose, uptake, thyroid disorder, and days of isolated hospitalization were recorded. The difference in mean dose rate with or without the collar was analyzed by t test or Mann-Whitney test, as appropriate. Twenty-eight patients (7 male, 21 female; mean age, 57 y; range, 29-82 y) were analyzed. Nine patients suffered from Graves' disease, 9 from toxic nodular goiter, and 10 from non-toxic nodular goiter. Patients were treated with a mean dose of 1,647 MBq 131I (range, 511-3,276 MBq). The mean anterior dose rates were 28 +/- 12 microSv-1 h at 1 m and 11 +/- 6 microSv-1 h at 1 m without and with the lead collar, respectively (p < 0.001). The mean reduction in dose rate for patients wearing the collar was 61 +/- 13%. The mean hospital stay was 2.6 +/- 1.3 days without the collar vs. 1.2 +/- 0.6 days with the collar (p < 0.001). A custom-made lead collar significantly reduced dose rates and could reduce compulsory hospitalization, especially in toxic- and non-toxic nodular goiter.