[gate-users] superimposed sources

Corinne J Groiselle corinne.groiselle at umassmed.edu
Wed Oct 6 15:32:38 CEST 2004

Hi all,

I know the question has already been asked but I can't find the answer 
in GATE-Talk, so I ask it again... O:-)
I simulated 6 hot spheres (R=1cm) in a warm cylinder (D=20cm, H=70cm). I 
want a contrast of 5:1. So I did the following to define the activity I 
wanted in each of the volumes:
for the cylinder: 214.6MBq
for each sphere: (5-1)x(214.6MBq/(pix10x10x70))x(4xpix1x1x1/3), eg. 
(5-1)x(Cylinder Activity / Cylinder Volume) x (Sphere Volume)
I used (5-1) and not 5 assuming there will be the annihilations from the 
cylinder AND from the spheres at the sphere location.

The problem is that I can't recover that contrast in the reconstructed 
data. Can someone tell me if I did something wrong in the activity setting?

Thanks a lot,

-- Corinne

Corinne J. Groiselle, PhD
Research instructor

Division of Nuclear Medicine / Department of Radiology
University of Massachusetts Medical School
55 Lake Avenue North
Worcester, MA 01655

_phone_: (508)-856-6123 - fax: (508)-856-4572
_e-mail_: Corinne.Groiselle at umassmed.edu
_professional homepage_: http://users.umassmed.edu/corinne.groiselle
_personal homepage_: http://corinne.groiselle.free.fr

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