[Gate-users] Gate SPECT

[vieira.lina at sapo.pt]

Dear Steven,

Thank you for your e-mail.
I write to you again to ask for some help, if possible, in some issues that are,
currently, problems for me, as I am trying to define the Script of the Gama
camera which I intend to simulate.
As I have been using the macro SPECTbenchmark which comes as an example of Gate,
I got to the conclusion that the constituents of the detector are merely:
-	SPECThead,
-	Shielding,
-	Collimator,
-	Crystal,
-	Back-compartment,
But in the article you published you describe what you simulated:
-	Collimator,
-	Cover,
-	Crystal,
-	Light guide,
-	PMTs,
-	Compression plate,
-	Air gap,
-	Lead ending.

a)	Is it possible for you to help by giving me the general guiding/command lines
to simulate: Cover, Light Guide and the PMTs?
Namely, how is the organization of the different PMTs that are behind the
Collimator?

b)	In what concerns to "Placing a volume is available to translation" as in
different constituents of the detector, how is the position of translation
given?
In the manual you refer "The position is always given with respect to the
center of the mother volume"(page 37)
Is it calculated in relation to the center for all the constituents? Or is it
considered, for example, for the crystal as being centered in point zero in the
three axis (x, y and z) and the remaining constituents are settled in order to
this constituent (the crystal)?

For example in SPECTbenchmark the following values are presented:

(...)
/gate/SPECThead/placement/setTranslation 20.0 0. 0. cm

(...)
/gate/shielding/placement/setTranslation 0. 0. 0. cm

(...)
/gate/collimator/placement/settTranslation -2. 0. 0. cm

(...)
/gate/crystal/placement/setTranslation 0. 0. 0. cm

(...)
/gate/compartment/placement/setTranslation 1.75 0. 0. cm

(...)
/gate/Phantom/placement/setTranslation 0. 0. -6. cm

(...)
/gate/table/placement/setTranslation 0. -5.3. 0. cm

How are the Translation values settled?

c)	In relation to the movement of a volume "around any axis during a
simulation using the orbiting motion", what do the following command lines
really mean:

/gate/SPECThead/orbiting/setPoint1 0. 0. 0. cm

/gate/SPECThead/orbiting/setPoint2 0. 0. 0. cm


d)	To end, I would still like to ask you if the graphic interface dedicated for
SPECT is the OpenGL - Open Stored - X, that is, if one needs to use:

/vis/open OGLSX

to visualise in SPECT?


	Thank you in advance for all the attention and help given.

	Gratefully,


Lina Vieira
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