H. Takekawa et al., RETENTION INDEX OF TL-201 SINGLE-PHOTON EMISSION COMPUTERIZED-TOMOGRAPHY (SPECT) AS AN INDICATOR OF METASTASIS IN ADENOCARCINOMA OF THE LUNG, British Journal of Cancer, 70(2), 1994, pp. 315-318
We examined the relationship between the retention of thallium-201 (Tl
-210) on a delayed scan and the metastatic potential of adenocarcinoma
s of the lung. We studied 43 patients with adenocarcinoma of the lung
and divided them into two groups according to the presence or absence
of lymph node metastasis. Tl-201 single photon emission computerised t
omography (SPECT) was conducted twice: 15 min (early scan) and 120 min
(delayed scan) after intravenous injection of 3 mCi of Tl-201 chlorid
e. We calculated the retention index in order to evaluate the degree o
f Tl-201 retention in the primary tumour. The retention indices were s
ignificantly higher in the group that was positive for lymph node meta
stasis than in the negative group. In adenocarcinomas with high metast
atic potential, Tl-201 SPECT demonstrated slow washout or increased re
tention on the delayed scan. The retention index of Tl-201 SPECT is a
useful indicator of metastatic potential, thereby facilitating the pre
diction of prognosis, and provides insight into the relationship betwe
en Tl-201 uptake and malignancy. This is the first report demonstratin
g a significant relationship between the retention of Tl-201 SPECT and
lymph node metastasis.