Introduction

Neuroblastoma, a neural crest derived tumor is most common extracranial malignant solid tumor of infant and children. These tumors express somatostatin receptors thus allowing PET/CT imaging with Ga-68 DOTA-peptide fortumor localization and response evaluation following chemotherapy/MIBG/ PRRNT. Aim of the study was to evaluate role of Ga-68 DOTANOC PET/CT in response evaluationof neuroblastoma patients following chemotherapy.

Material & methods

In this retrospective study we evaluated 24 patients (M-18, F-6) of neuroblastoma with mean age of 4.2years (range 1-12 years). All the patients underwent whole body Ga-68 DOTANOC PET/CT before after the chemotherapy after intravenous injection of 74 to111 MBq of Ga-68 DOTANOC using dedicated BGO PET/CT scanner. The response to the chemotherapy on PET/CT was evaluated qualitatively and semi-quantitatively (decrease/ increase in size, numbers or tracer avidity of lesions) by two experienced nuclear medicine physicians.

Results

Baseline PET/CT localized only primary tumor in two patients; primary tumor with lymph nodes in five patients;primary tumor and skeletal metastases in two patients;primary tumor, lymph nodes and skeletal metastases in eight patients; primary tumor, lymph nodes, skeletal &livermetastases in one patient. Only metastatic disease was noticed in six patients (lymph nodes & skeletal metastases-2 and lymphnodes, skeletal and soft tissue metastases-4). The favorable response to chemotherapy was noticedin 19 patients, disease progression in 3 patients, no significant change in 1 patient and suspicious lesion for residual disease in 1 patient. The mean SUVmax of primary tumor was 7.8 (range of 0-23.7) in baseline PET and 4.1 (range 0-8.6) in post-chemotherapy PET. However mean SUVmax at metastatic site was 13.2 (9.8-18.1) in the baseline and 6.6 (4.7-8.2) in post chemotherapy PET.

Conclusion

The study showed usefulness of Ga-68 DOTANOC PET/CT in initial staging to assess burden of disease and subsequently chemotherapy response evaluation.