Comparison of I-123 MIBG scintigraphy with somatostatin receptor scintigraphy using Tc-99m HYNIC TATE in neuroblastoma patients

Objectives Neuroblastoma (NB) is one of the most common and aggressive malignancies in childhood. Besides morphological imaging, scintigraphical imaging using I-123 MIBG (M) is critical in its staging and follow-up. Recently, few studies related to NB imaging using FDG or octreotide (OC) analogues and molecular radiotherapy based on OC receptors has been introduced. Tc-99m HYNIC TATE (H) is another OC analogue with strong affinity to Sst-2. It is advantageous in its high imaging quality, low radiation burden, availability and cost-effectiveness. Aim of this study was to evaluate the value of H with M in diagnosis and staging of NB patients (pts) and to compare their results with MRI.

Methods Study group was composed of 11 NB pts (8 F, 3 M, median age: 4 y (1-13 d)), who were evaluated with both M and H scans performed on different days (median interval inbetween: 21 d (8-416 d). Whole body planar and SPECT images were taken and compared by 2 different nuclear medicine specialist. MRI, bone scan and tumor markers were available.

Results Total 42 lesions were detected in 11 pts using both M and H scans. Of these 42 lesions, 32 (76,2%) were M positive and 39 (92,6%) were H positive. H revealed 10 extra lesions, which could not be detected with M, on contrary, M revealed 3 extra lesions. Statistically no difference was observed between 2 scans (p=0,092). When compared on patient basis, 5 pts were found to be lesion free in both scans and 6 pts had at least one lesion positive with both scans.

Conclusions H scan is found to be a comparable and useful diagnostic modality in NB patients. It can be used as a complementary approach, and it is especially crucial for subgroup of pts who are refractory to conventional treatment modalities and therefore referred to somatostatin receptor therapy