Evaluation and comparison of Ga-68 DOTA-TATE and Ga-68 DOTA-NOC PET/CT imaging in well-differentiated thyroid cancer.
BACKGROUND
Somatostatin receptor (Sstr) scintigraphy with radiolabelled somatostatin analogues has been used extensively for the diagnosis and therapy of Sstr-expressing tumours. It has been shown that well-differentiated thyroid cancer (WDTC) cells have a high expression of Sstr2, Sstr3 and Sstr5. Hence, WDTC cells could be an ideal target for the evaluation of lesion uptake of Ga-68 DOTA-1-NaI3-octreotide (DOTA-NOC), which has a high affinity not only to Sstr2 but also to Sstr3 and Sstr5. The aim of the present study was to evaluate the value of Ga-68 DOTA-NOC as a target for Sstr2-expressing, Sstr3-expressing and Sstr5-expressing tumours in WDTC patients and to compare the results with those of Ga-68 DOTA-TATE in the same patient population.


METHODS
Thirteen patients with WDTC were included in our study: nine with papillary thyroid cancer, three with Hurthle cell carcinoma and one with follicular thyroid carcinoma. All patients had elevated serum thyroglobulin levels and negative post-therapeutic I-131 whole-body scans, which were obtained after the last radioiodine treatment. All patients had undergone two consecutive PET imaging studies with Ga-68 DOTA-D-Phe1-Tyr3-octreotate (DOTA-TATE) and Ga-68 DOTA-NOC, respectively. All images were evaluated visually, and maximum standardized uptake values were calculated.


RESULTS
Both Ga-68 DOTA-TATE and Ga-68 DOTA-NOC PET images gave comparable results. Among the 13 patients, imaging with both Ga-68 DOTA-TATE and Ga-68 DOTA-NOC gave negative results in five (38%) patients and positive results in eight (62%) patients. A total of 45 lesions were identified on Ga-68 DOTA-TATE images and 42 on Ga-68 DOTA-NOC images; three lesions were missed. Lesion uptake was significantly higher on Ga-68 DOTA-TATE images. Maximum standardized uptake values of Ga-68 DOTA-TATE and Ga-68 DOTA-NOC were 12.9±9.1 and 6.3±4.1 (n=54, P<0.001), respectively.


CONCLUSIONS
Our study suggested that Ga-68 DOTA-TATE has a higher lesion uptake even in WDTC patients and may have potential advantage over Ga-68 DOTA-NOC.
aDepartment of Pharmaceutical Technology, Faculty of Pharmacy bDepartment of Nuclear Medicine, Cerrahpasa Medical Faculty cDepartment of Physical Chemistry, Faculty of Sciences, Istanbul University, Istanbul, Turkey.
Meltem
M
Ocak
Emre
E
Demirci
Levent
L
Kabasakal
Aslan
A
Aygun
Rumeysa O
RO
Tutar
Ahmet
A
Araman
Bedii
B
Kanmaz
D018263:Adenocarcinoma, Follicular / Q000000981:diagnostic imaging*; D018249:Adenoma, Oxyphilic; D000328:Adult; D000368:Aged; D018931:Antineoplastic Agents, Hormonal; D002277:Carcinoma / Q000000981:diagnostic imaging*; D002291:Carcinoma, Papillary; D005260:Female; D005710:Gallium Radioisotopes; D006801:Humans; D008297:Male; D008875:Middle Aged; D015282:Octreotide; D009942:Organometallic Compounds; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
C504894:68Ga-DOTANOC; D018931:Antineoplastic Agents, Hormonal; D005710:Gallium Radioisotopes; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; C513399:gallium Ga 68 dotatate; D015282:Octreotide