Aim: We undertook a study to evaluate whether Lutetium (Lu) DOTATATE whole body scan is well comparable to Gallium positron emission tomography (PET) / Indium Octreotide, and hence with dosimetric advantage can replace it in the pre-therapy setting.
Materials and methods: We undertook a prospective study of a total of 39 patients with metastatic neuroendocrine tumor (age 11-70 years), who underwent Lu-DOTATATE scans within the period August 2009-November 2010. This included 28 males and 11 females. Dose of Lu-DOTATATE injected for diagnostic scanning purpose was 10 mCi i.v. Whole body planar images and single-photon emission computed tomography (SPECT)-CT images were obtained at 4, 24 and 48 hours. The Lu-DOTATATE whole body and SPECT-CT images were compared to contrast CT scans in all patients, and Indium Octreotide and Gallium DOTATATE PET images in nine patients, with reference to detection sensitivity of number of lesions. The pre-therapy scans were also used for dosimetric calculations. Fourteen of these 39 patients further went ahead with Lu-DOTATATE therapy.
Results: All 39 patients demonstrated Lu-DOTATATE uptake in the disease sites seen on the contrast CT images. The uptake intensity was well comparable to Indium Octreotide and Gallium DOTATATE PET scans of all nine patients, with equally well-defined lesions. The post-therapy Lu-DOTATATE scans of the 14 patients who underwent therapy demonstrated higher intensity uptake pattern in the same disease sites, suggesting favorable therapeutic effect. The scans were useful in determining dosimetric details for therapeutic purpose and adequate exposure rates to suggest good ablative effect.
Conclusion: Our preliminary data suggest that Lu-DOTATATE whole body scanning procedure is cost effective and equally sensitive as Gallium DOTATOC/NOC PET scan in pre-therapy setting of neuroendocrine tumors. The additional advantage of dosimetry calculations on this scanning procedure makes it more ideal to tailor therapies with more accuracy.
Keywords: Lutetium DOTATATE; neuroendocrine tumors; pre-therapy; whole body scan.