Feasibility of Single Time Point Dosimetry Application in 177 Lu-DOTATATE/DOTATOC-treated Pediatric Neuroblastoma

177 Lu-DOTATATE/DOTATOC peptide receptor radionuclide therapy (PRRT) has demonstrated potential for treating pediatric neuroblastoma (NB), and in clinical practice can be measured dosimetry by multi-time point (MTP) dosimetry. However, the high workload and limited patient compliance associated with MTP restrict its application. Consequently, single time point (STP) dosimetry approaches have emerged as a promising alternative, though their effectiveness in pediatric populations has not been thoroughly investigated. This study aimed to assess the dosimetric determination of 177 Lu-DOTATATE/DOTATOC in pediatric neuroblastoma patients to determine whether STP could serve as a viable replacement for MTP.

A total of 24 pediatric NB patients who received 1 to 2 cycles of 177 Lu-DOTATATE or 177 Lu-DOTATOC underwent dosimetric measurement of lesions and critical organs using the 96 hours single time point (STP H ) dosimetry method proposed by Hänscheid and colleagues. The results were compared with those obtained from standard MTP.

In patients treated with 177 Lu-DOTATATE, the mean relative deviation absolute values of the STP H -calculated absorbed dose from MTP were <10% for lesions, kidneys, bone marrow, liver, and spleen, with Pearson correlation coefficients of 0.99, 0.93, 0.97, 0.84, and 0.84, respectively. In patients treated with 177 Lu-DOTATOC, the mean relative deviation absolute values for kidneys, spleen, and bone marrow were <10%, with Pearson correlation coefficients of 0.97, 0.77, 0.35, 0.48, and 0.93 for lesions, kidneys, bone marrow, liver, and spleen, respectively.

The findings confirm that the 96 hours STP H method can reliably replace MTP for dosimetric assessment in pediatric NB patients treated with 177 Lu-DOTATATE and performed well in renal dosimetry for 177 Lu-DOTATOC therapy.