[Gate-users] question about the MOBY phantom

[yuxuan.zhang at di.mdacc.tmc.edu]

Hi,

I am using the MOBY phantom to do some simulation for quite a while. 
However, I 
have some question about the SUV values in this phantom. I hope someone 
may give
me some advises.

I concern is about how to setup the activity in different organs. Because 
I don't
know the SUV value of these organs, so I just use the default value 
provided by
the general.samp.par from the MOBY developer. Some of the value are listed 
here:

  Body             =       2.0000
  Liver            =      75.0000
  Lung             =       4.0000
  Stomach Wall     =       2.0000
  Stomach Contents =       2.0000
  Kidney           =      75.0000
  Spleen           =      75.0000
  Small Intestine  =       2.0000
  Bladder          =      20.0000
  Vas deferens     =      10.0000
  Testes           =      15.0000
  Wet Spine Bone   =       2.0000
  Wet Rib Bone     =       2.0000
  Skull            =       2.0000

  Brain (backgrnd)     =       5.0000
  Neocortical white    =      25.0000
  Neocortical gray     =      20.0000
  Cerebellar white     =      15.0000
  Cerebellar gray      =      10.0000
  Cerebellar nuclei    =      30.0000
  Thalamus             =      35.0000
  Hippocampus          =      40.0000
  Thyroid              =      47.0000

  LV Myocardium    =      75.0000
  LA Myocardium    =      75.0000
  RV Myocardium    =      75.0000
  RA Myocardium    =      75.0000

  LV Blood pool    =       2.0000
  LA Blood pool    =       2.0000
  RV Blood pool    =       2.0000
  RA Blood pool    =       2.0000



>From the data above, we can see that the background value is 2, and the 
values of liver, kidney, spleen 
are 75, which means a suv value of ~37.5. Is this number reasonable or 
it's a little bit high.

Also in the sample file there were definitions as follow:

55.0            : large intestine air activity;
69.0            : small intestine air activity;

which mean the large intestine air has a suv of 25.5, and small intestine 
air has the suv 34.5. 
First, what are the intestine air? From the attenuation map those parts 
has the same attenuation coefficient as
the lung, are they some kind of gas in the intestine? Second, why they has 
such big suv value? 

If someone has some experience with the real animal, could you make some 
comments on this issue? Thank you.


Yuxuan


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