Abstract
This prospective study included 35 patients suffering from Graves' disease (GD) clinically
and biologically confirmed by endocrinologists, sent to the nuclear medicine department
of CHU de Bab El Oued, Algiers for iodine-131 therapy. CHU de Bab El Oued is a tertiary
hospital located in the center of the capital Algiers. The aim of this study is to
propose a simplified dosimetric procedure which will initiate iodine-131 therapy of
GD in particular and hyperthyroidism in general in Niger. The determination of the
maximum uptake was performed with a Biodex external probe at 2 h, 4 h, and 24 h after
the administration of 3 MBq of liquid iodine-131. The iodine-131 activities were determined
using the Marinelli formula with a predefined effective half-life (Te) of 5 days and subsequently extrapolated half-life with kaleidagraph software. The
statistical analysis was performed using an excel sheet and analyzed using the software
package Statistica 10 (stat Soft, Tulsa, USA). the male:female gender ratio was1:4.5
and the mean age was 42.56 years (±7.14). The body mass index was within normal range
with a value of 25.25 kg2 (±0.42) and the mean average thyroid mass was equal to 24.05 (±10.53) g. The mean
uptake value at 24 h was 43.24% (±17.68%) meanwhile the maximum uptake value was 46.28
(±21.13%). The estimated effective half-life (Te) was 5.44 days (±1.96) days which were different from the predefined Te of 5 days. The mean activity determined with fixed Te and 24 h uptake was 244.45 (±109.2) MBq and the mean activity calculated with both
extrapolated Te and maximum uptake was 452.22 (±381.9) MBq. Empirical determination of activity in
the treatment of GD gives higher activities (1.5 times) to patients than dosimetric
methods based on the determination of extrapolated effective half-life.
Keywords
Dosimetry - empiric activities - extrapolated effective half-life - optimization -
planning - predefined effective half-life - uptake
