PHARMACOKINETICS OF TC-99(M)-PERTECHNETATE AND RE-188-PERRHENATE AFTER ORAL-ADMINISTRATION OF PERCHLORATE - OPTION FOR SUBSEQUENT CARE AFTER THE USE OF LIQUID RE-188 IN A BALLOON CATHETER
J. Kotzerke et al., PHARMACOKINETICS OF TC-99(M)-PERTECHNETATE AND RE-188-PERRHENATE AFTER ORAL-ADMINISTRATION OF PERCHLORATE - OPTION FOR SUBSEQUENT CARE AFTER THE USE OF LIQUID RE-188 IN A BALLOON CATHETER, Nuclear medicine communications, 19(8), 1998, pp. 795-801
Radioactive wires and other linear sources are currently being used in
clinical trials as endovascular brachytherapy to prevent restenosis a
fter percutaneous transluminal coronary angioplasty. A new concept is
the use of a liquid-filled balloon containing a beta-emitting radioiso
tope. A major advantage is optimal delivery of the radioactivity to th
e vessel wall. Rhenium-188 (Re-188) is a high-energy beta-emitter that
is routinely available from a W-188/Re-188 generator in liquid form.
Since Re-188-perrhenate could be released in the unlikely event of bal
loon rupture, we investigated whether, in analogy to pertechnetate, su
bsequent use of perchlorate can reduce the uptake of perrhenate in the
thyroid. We performed static (n = 9) and dynamic (n = 11) thyroid sci
ntigraphy with Tc-99(m)-pertechnetate to estimate the overall reductio
n in activity within 30 min and the washout from the thyroid after ora
l administration of 600 mg perchlorate (T-1/2). In two patients, Re-18
8 was injected to estimate the whole-body distribution and the dischar
ge of thyroid activity after perchlorate use. Based on MIRD Dose Estim
ate Report No. 8 (valid for Tc-99(m)-pertechnetate), the radiation bur
den was calculated for intravenous administration of Re-188 and compet
itive blocking with perchlorate. In 20 patients, Tc-99(m) uptake by th
e thyroid was reduced by 85% within 30 min by perchlorate. The mean (/- S.D.) washout rate (T-1/2) was 8 +/- 2 min in 11 patients. Perrhena
te showed a whole-body distribution similar to that of pertechnetate a
nd the thyroid activity could be displaced (T-1/2 = 6.3 and 9.3 min, r
espectively) by oral administration of perchlorate, with reductions in
uptake of 83% and 75% within 30 min, respectively. Whole-body scannin
g demonstrated no regional accumulation of Re-188-perrhenate with excr
etion by urine. Dose estimates gave an effective dose equivalent of 0.
42 mSv MBq(-1), which decreased to 0.16 mSv MBq(-1) after perchlorate
blocking. Re-188 has favourable properties for endovascular brachyther
apy via a balloon catheter and, in the unlikely event of balloon ruptu
re, whole-body radiation can be reduced to 38% by subsequent oral admi
nistration of perchlorate. ((C) 1998 Lippincott Williams & Wilkins).