[Gate-users] Problem for creating source of 131 I type histogram

[Thibault Mauxion]

HI Juan Camilo, 

I cant' find the example you're referring at.... However you're right : 

First column corresponds to energy in MeV and second to the intensity. 


But you should be very careful when using histograms since your data may represent either density probability (definition at a particular point of the distribution) or cumulated "counts" in bins. 
As far as I know, GATE automatically extrapolate the energy distribution between 2 values that are entered in the histogram. That means your histogram is never discrete. 

This is fine for continuous energy distribution, such as ß- emission from 131-I, that can be described by density probability. You should therefore use : 
[prefix]/energytype Arb
[prefix]/histname arb

and (just a example of few points for ß)

/gate/source/betaminus/gps/histpoint	0.07000		3.209
/gate/source/betaminus/gps/histpoint	0.07500		3.185
/gate/source/betaminus/gps/histpoint	0.08000		3.161
/gate/source/betaminus/gps/histpoint	0.08500		3.136
/gate/source/betaminus/gps/histpoint	0.09000		3.11
/gate/source/betaminus/gps/histpoint	0.10000		3.055
/gate/source/betaminus/gps/histpoint	0.11000		2.999
/gate/source/betaminus/gps/histpoint	0.12000		2.939
/gate/source/betaminus/gps/histpoint	0.13000		2.877
/gate/source/betaminus/gps/histpoint	0.14000		2.812


But for mono-energetic photon and electron emissions,the only way (at least i know) to define a discrete distribution is to create "dummy values" set to zero in between. This will force the histogram to zero between 2 emission energies. In that case you should use : 

[prefix]/energytype User
[prefix]/histname energy

and (this is again just an example taken for 3 gamma rays, including the main one)

/gate/source/mono_ph/gps/histpoint	3.58400E-01		0
/gate/source/mono_ph/gps/histpoint	3.58400E-01		1.63400E-04
/gate/source/mono_ph/gps/histpoint	3.58400E-01		0
/gate/source/mono_ph/gps/histpoint	3.64489E-01		0
/gate/source/mono_ph/gps/histpoint	3.64489E-01		8.17000E-01
/gate/source/mono_ph/gps/histpoint	3.64489E-01		0
/gate/source/mono_ph/gps/histpoint	4.04814E-01		0
/gate/source/mono_ph/gps/histpoint	4.04814E-01		5.47390E-04
/gate/source/mono_ph/gps/histpoint	4.04814E-01		0
   
Now, as far as the comparison of the values is concerned, if you can tell me which example you use, we may be able to give you more info. 
I use data from MIRD (Eckerman KF, Endo A. MIRD:Radionuclide Data and Decay Schemes Society for Nuclear Medicine;; 2008) as you also seem to do, but had similar results with RADAR (Stabin MG, da Luz LC. Decay data for internal and external dose assessment. Health Phys. Oct 2002;83(4):471-475.). Data from nudat2 are also fine. 

For beta distribution, the only thing you need to be careful with is, again, whether you're dealing with intensity defined in cumulated bin values or density probabilities. 

I hope this helps :) 

If i remember correctly, you'll also find some answers for your problem in user list archives.

Good luck !

Thibault 


INSERM UMR 1037
Cancer Research Cancer - Toulouse, France 
Faculté de Médecine de Toulouse-Rangueil
Biophysique - Bâtiment A3
133 route de Narbonne
31062 Toulouse
Tel: 	 	05 62 88 90 81
Port : 	06 29 53 50 77
Mail: thibault.mauxion at inserm.fr


Le 8 oct. 2012 à 22:56, juan camilo bedoya tobon a écrit :

> Good afternoon.
> 
> My name is Juan Camilo Bedoya, in the moment i am realizing a simulation of the source de 131 I, I was watching  the example of internal dosimetry; but i do not undestand how to build a source type histogram.
> 
> 
> I think, thqt the fist column represente te energy en Mv and the second the intensity in %, but when i compare the example with the spectrun en la nist (http://www.nndc.bnl.gov/nudat2/), are totally diferent.
> 
> 
> Because the reason, i write the present mail, for ask how to build the source and and where to get the data, because I have the MIRD.
> 
> I also would like to know if anyone has the MIRD 2008 to pay me.
> 
> I hope someone can help me.
> 
> 
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> Gate-users at lists.opengatecollaboration.org
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