DEPARTMENTS Letters to the Editor

TO THE EDITOR: Dorn et al. have described a dosimetry-guided approach for calculating the largest “safe ” dose of 131I for treatment of differentiated thyroid cancer (1). With this method, a maximal dose was determined assuming an upper limit of 3 Gy for the absorbed dose to the bone marrow or 30 Gy to the lungs. Their method used an initial tracer dose of 150–400 MBq (4–10.8 mCi) of 131I with serial dosimetric imaging for 4–5 d, followed by administration of the maximal treatment dose of 131I. The authors stated that this approach was intended to achieve “the maximum therapeutic benefit. ” However, the outcome data presented in Table 4 do not appear to support this claim. From this table, thyroglobulin was 100 in 29 therapy instances. After 131I treat-ment, 20 of these 29 instances (69%) still had a thyroglobulin level of 100. The average survival of 29 patients who received “cur-ative-intent ” therapy was 4.1 y. Even after excluding patients olde