[Gate-users] How to get the linear attenuation coefficients ?

[Priegnitz, Marlen]

Hi Joe,

it is no problem to calculate the chemical formular of a material, if the mass 
fraction of all components are given.
Just divide the mass fraction by the Molar Mass.
For Skull you get (if I did no mistake):
H 0.0496
C 0.01765
N 2.8557 E-3
O 0.02719
Na 4.3497 E-5
Mg 8.227 E-5
P 2.61543 E -3
S 9.357 E-5
Ca 4.3923 E-3

You can normalize these values to the smallest, then you get for example
H 1140.3 C 405.8 N 65.7 O 625.1 Na 1 Mg 1.9 P 60.1 S 2.15 Ca 101
You can normalize it also differently, for example that the sum of all is 1. 
You can do it as you like, the result is the same.

So for brain you get:
H 0.10615
C 0.01207
N 1.5706 E-3
O 0.0445
Na 8.6994 E-5
P 1.2916 E-4
S 6.2383 E-5
Cl 8.4626 E-5
K 7.6726 E-5
The normalization you can do on your own.

Hope this helps.
Please check all the values on your own. Maybe I did a typing mistake or 
something else.

Marlen





Am Fri, 21 Aug 2009 16:17:06 +0200 schrieb Joe Aoun <joe.aoun at imag.fr>:
> Thank you Sebnem and Niklas for your fast answers !!
> 
> Well actually, I am using two materials in my GATE simulation, the Brain and 
>the Skull.
> These two materials are defined in the "GateMaterials.db" file by their 
>density and the mass fractions of each element.
> 
> Now If I want to use the NIST database, then I will need the chemical 
>formula of my material (brain & skull).
> Does anyone know the chemical formula of the brain and the skull ?
> 
> If not, is there any program which takes as an input the mass fractions of 
>the elements rather than the chemical formula of the compounds ?
> 
> Thank you in advance !!
> 
> Joe
> 
> 
> 
> 
> sebnem erturk a écrit :
>> Hi Joe,
>>  
>> You can use XCOM program  to learn linear attenuation coefficients. (you can 
>>download this program from  below link)
>> unit of linear attenueation coefficent is cm^-1.
>>  
>> μ_l is called the linear attenuation coefficient of the absorber. It has 
>>dimensions (thickness)^-1 and usually is expressed in cm^-1
>> http://physics.nist.gov/PhysRefData/Xcom/Text/XCOM.html
>>  
>> hope it helps,
>>  
>> sebnem
>>
>>
>> On Fri, Aug 21, 2009 at 2:36 PM, Joe Aoun <joe.aoun at imag.fr 
>><mailto:joe.aoun at imag.fr>> wrote:
>>
>>     Dear Gate users,
>>
>>     Does anyone know how to get the linear attenuation coefficient
>>     values of the different materials used in a GATE simulation ?
>>     And what is the unit of the coefficients ?
>>
>>     Thank you for your help !!
>>
>>     Regards,
>>
>>     Joe
>>
>>     --     ============================================
>>     Joe Aoun
>>     Laboratoire TIMC-IMAG
>>     Équipe GMCAO
>>     Université Joseph Fourier - Faculté de médecine
>>     Domaine de la Merci
>>     38706 La Tronche - France
>>     Tel. +33 (0)4 56 52 00 12
>>     Fax  +33 (0)4 56 52 00 55
>>     Sec. +33 (0)4 56 52 00 07
>>     E-mail: Joe.Aoun at imag.fr <mailto:Joe.Aoun at imag.fr>
>>
>>     _______________________________________________
>>     Gate-users mailing list
>>     Gate-users at lists.healthgrid.org
>>     <mailto:Gate-users at lists.healthgrid.org>
>>     http://lists.healthgrid.org/mailman/listinfo/gate-users
>>
>>
>>
>>
>> -- 
>> Sebnem Erturk
>> University of Pisa
>> Applied Physics Dpt.
>> Largo Pontecorvo
>> 56127 Pisa-Italy
>> Office :0039 050 2214346
>> Mobile :0039 345 3331440
>> http://www.df.unipi.it/~fiig/ <http://www.df.unipi.it/%7Efiig/>
> 
> _______________________________________________
> Gate-users mailing list
> Gate-users at lists.healthgrid.org
> http://lists.healthgrid.org/mailman/listinfo/gate-users