Will thallium-201 replace gallium-67 in salivary gland scintighaphy ? J Nucl Med 1996; 37:1819-1823.
Published byModified over 4 years ago
Presentation on theme: "Will thallium-201 replace gallium-67 in salivary gland scintighaphy ? J Nucl Med 1996; 37:1819-1823."— Presentation transcript:
Will thallium-201 replace gallium-67 in salivary gland scintighaphy ? J Nucl Med 1996; 37:1819-1823
Purpose: We investigated and compared finding on combined99mTc pertechnetate-201Tl with those 99mTc pertechnetate-67Ga scintiscans to elucidate the advantages of 201Tl in detecting various salivary glands disorders.
Methords: We studied 23 patients: 6 had sialadenitis, 12 had benign tumors and 5 had malignant tumors. All but four patients had undergone 99mTc (before and lemon stimulation), 201Tl ( early and delay ) and 67Ga imaging.
Sialadenitis The criterion for diagnosis of sialadenitis was various degrees of diffuse 99mTc uptake with positive 67Ga accumulation, all but one patient with sialadenitis fulfilled this criterion. If we consider various degrees of diffuse 99mTc uptake and early diffuse uptake without retention of 201Tl as criterion for sialadenitis, five of six patients fulfilled
67Ga, 201Tl scan results show that both agents have similar sensitivity in detecting sialadenitis, but 201Tl has the advantages and convenience and time-efficiency 67Ga: 72 hr after injection 201Tl: 2-4 hr after injection
Benign tumor Except for Warthin ’ s and oncocytoma, most tumors appear as cold defects on 99mTc scan. Of the 9 benign cold lesions on 99mTc scan, 67Ga depicted five false-positive scans, whereas 201Tl demonstrated various degrees of uptake without retention on delay images for all patients except one
Malignant tumor (1) Of the five malignant cold lesions on 99mTc scan, both 67Ga and delay 201Tl imaging had two false-negative results. 201Tl detected the tumor as well as lymph node metastasis in one patient. In detecting malignant tumor, both 201Tl and 67Ga had similar results, but 201Tl detected cystic change in one patient.
Malignant tumor (2) Delayed 201Tl scan and 67Ga scan are compared for all patients, the sensitivity and specificity in detecting malignancy : 201Tl : SEN=60%(3/5) SPE=73%(11/15) PPV=43%(3/7) NPV=85%(11/13) 67Ga : SEN=60%(3/5) SPE=47%(8/17) PPV=25%(3/12) NPV=80%(8/10)
Conclusion: 67Ga scan were nonspecific in differentiating benign from malignant tumor due to high uptake by inflammation 201Tl has already shown its potential to differentiate benign from malignancy and retention of 201Tl in tumor2-4 hr after injection increases the probability of malignancy. Both 201Tl and 99mTc scan can be performed within a single day
Conclusion: 99mTc / 201Tl imaging of salivary gland disorders may be superior to 99mTc / 67Ga imaging due to sensitivity and specificity in detecting malignancy, convenience for both patients and technologists.