The document reads:2.0 millicuries of radioactive iodine
It is supposed to be a low dose. What did Pallina get?
...the cat was treated by intravenous injection of 1.7 mCi (=62.5 MBq) iodine-131...
...upon release the measured level of emitted radiation is 1.0 uSv/h at 1 meter...
...the cat is found in good clinical condition to be transported...
So it seems that Pallina received a lesser amount of radiations, despite the fact that her HT was diagnosed at least 12 months before the treatment.
Pallina was examined with a scintigraphy scan 24 h prior to the I-131 shot:
...a diagnostic pertechnetate scan was performed. For this, , the cat is injected intravenously with pertechnetate, a radioisotope emitting gamma radiation.
The cat received an activity of 1.2 mCi (=44.4) MBq Na99mTcO4.
As far as I know, this radioactive substance has a half-life of few hours, so it's unlikely that this added to the following radiation level.