Abstract / Summary
Aim: Pretherapeutic dosimetry is an essential component of individualized radioiodine therapy. This study aimed to compare radioiodine therapies planned according to the Marinelli equation or DIN 6861-1:2021-11 with regard to the deviation of the planned and achieved thyroid doses in patients with benign thyroid diseases.
Methods: The relative deviation of the achieved thyroid dose during radioiodine therapy from the pretherapeutically planned dose was analyzed according to the applied dosimetric method. Patient cohorts with goiter, recurrent goiter, disseminated and focal thyroid autonomy and autoimmune thyroid disease were evaluated. The cohorts were compared using the Mann-Whitney U- test.
Results: For goiter, recurrent goiter, disseminated thyroid autonomy and focal thyroid autonomy, radioiodine therapies planned according to DIN 6861-1:2021-11 were associated with significantly smaller deviations between the planned and achieved thyroid doses than therapies planned according to the Marinelli equation. Depending on the diagnostic group, the mean relative deviation was approximately 15 to 32 percentage points lower in the DIN cohorts. The DIN cohorts also showed less variability in dose deviations. In patients with autoimmune thyroid disease, no statistically significant differences of the mean relative deviation were observed between the dosimetric methods. However, variability was also lower in the DIN cohorts.
Conclusion: The use of DIN 6861-1:2021-11 is associated with improved prediction of the thyroid dose compared with the Marinelli equation and may contribute to more precise individualized planning of radioiodine therapy in patients with benign thyroid diseases.