re: shielding for detector

[shafer@jumprun.ehs.uiuc.edu (Paul W. Shafer)]

Dear sir:

Please contact Dr. Seymour J. Raffety at 608-689-2331 or LACBWR, PO Box 275, Genoa,  
Wisconsin, USA....he will tell you all about excellent shields for a 3 X 3 or HPGe
detector system used for In-vivo analyses.


Paul W. Shafer
University of Illinois

Begin forwarded message:

Date: Fri, 11 Nov 94 07:02:07 -0600
Errors-To: mandel@romulus.ehs.uiuc.edu
Reply-To: radsafe@romulus.ehs.uiuc.edu
Originator: radsafe@romulus.ehs.uiuc.edu
Sender: radsafe@romulus.ehs.uiuc.edu
Precedence: bulk
From: cast@epcaba.bologna.enea.it
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Subject: I-125 thyroid detector
X-Listserver-Version: 6.0 -- UNIX ListServer by Anastasios Kotsikonas
X-Comment:  Radiation Safety Distribution List 



I would like to know if someone can give me some indication about direct 

measurement of iodine radioisotopes in thyroid by means of a thin window NaI(Tl) 

crystal.
We are looking forward putting a 0.2 window NaI(Tl) 3"x3" in our WBC cell to 

make simultaneously measurements to the whole body (with a 9"x4" crystal) and 

thyroid. We are looking forward the detection of I-125 (this is the reason of 

the thin window) and I-131 and I-123. 


Can someone help me in design the shelding of the 3"x3" crystal?

I would like to kwow, if someome has experience :

1)	crystal lateral shielding thickness
2) materials used in shielding (e.g. Pb, Cu, Al etc ) and relative thickness
3)	shape and geometry of collimator (cylindric, truncate conical with major  
base 

to the neck of the patient,truncate conical with major base to the detector, 

etc.)
4) calibration methodologies and phantoms 

5) minimum detectable activities achievable for I-131, I-125, I-123.

Can you also give me some references related to this issue.

I thank you in advance.

Carlo-Maria Castellani
ENEA Institute for Radiation Protection
Italy
Carlo-Maria CASTELLANI
ENEA Rad. Prot. Institute
BOLOGNA - Italy