AW: [ RadSafe ] Linearity with Tc99m shortage?

[Franz Schönhofer]

Ward,

There are typing errors in (both) your messages: Thallium has the chemical
symbol "Tl" and the isotoped used in cardiac medicine is Tl-201. "Tc-99" is
never used, not only because it is a pure beta emitter which cannot be used
for szintigraphy, but also because of its long half-life (211 100 years) and
therefore very low specific activity. What is used is the metastable Tc-99m
as a pure gamma-emitter and with a short half life of 6 hours, which is very
favourable with regard to patient radiation protection considerations. 

Interesting to read that one can use either radionuclide - I had the
impression that they are used according to different diagnostic tasks. I
remember that after my coronary infarction I underwent two tests with both
Tl-201 and Tc-99m. Maybe somebody on RADSAFE can explain this?

Best regards,

Franz

Franz Schoenhofer, PhD
MinRat i.R.
Habicherg. 31/7
A-1160 Wien/Vienna
AUSTRIA


-----Ursprüngliche Nachricht-----
Von: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] Im Auftrag
von Brunkow, Ward
Gesendet: Freitag, 07. Dezember 2007 15:05
An: Diane Griffiths; radsafe at radlab.nl
Betreff: RE: [ RadSafe ] Linearity with Tc99m shortage?

It is my understanding that most medical facilities use Thallium anyway
over TC99 for Cardiac stress tests, it is much cheaper but has much
longer T 1/2. The last time I had the procedure I requested Tc99 as I
didn't want the longer T1/2 while working in a highly restricted nuclear
facility, and they accommodated me, who know what they charged the
insurance company.  

Ward

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of Diane Griffiths
Sent: Friday, December 07, 2007 4:28 AM
To: radsafe at radlab.nl
Subject: [ RadSafe ] Linearity with Tc99m shortage?

I know we have discussed that hospitals can't get the Tc99m for patient 
studies, this brings me to another question.. How can we do linearity on
the 
Dose Calibrators?

I have two locations where the linearity is due by the end of this
month, 
and they can't get any Tc99m at all. They have switched their cardiac 
procedures to Thallium until the shortage is over.

Diane

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