[Gate-users] Meaning of the positron annihilation distance?

[Park MinJae]

Dear Gaters,

I found the equation in Gate source...
G4ThreeVector posAnnihilDist = m_positronAnnihilPos -
m_positronGenerationPos;

Therefore, I can conclude that the positron annihilation distance is a
distance from positron generated position to positron annihilated
position...so called positron range...

However, accroding to PMB 44:781-799, 1999, maximum positron range of F-18
is 2mm and peak at the center is higher.


This is quite different from the result of Gate simulation...


I simulated again with the water sphere (r=35mm) and Flour18 positron source
at center (r=0.001mm sphere).

I got the same graph which I attached...


Look forward any comments...

Cordially yours,
MJ

//=================================================
//  Park MinJae
//  SNU BME Ph.D. Candidate
//
//  DialTo:+82-17-711-7809
//  MailTo:MJ at ToTi.us
//
//  Make the Dream True...
//=================================================

-----Original Message-----
From: gate-users-bounces at lists.healthgrid.org
[mailto:gate-users-bounces at lists.healthgrid.org] On Behalf Of Park MinJae
Sent: Thursday, June 25, 2009 12:00 PM
To: gate-users at lists.healthgrid.org
Subject: [Gate-users] Meaning of the positron annihilation distance?


Dear gaters,

When I simulated positron range of F-18 using a very small F-18 in a large
sphere filled with water, I got a attached graph...

However, I wonder that the positron annihilation distance is positron range.

I can guess that positron annihilation distance is tracked distance or
tangential distance.

Thanks in advance
Cordially yours,
MJ

//=================================================
//  Park MinJae
//  SNU BME Ph.D. Candidate
//
//  DialTo:+82-17-711-7809
//  MailTo:MJ at ToTi.us
//
//  Make the Dream True...
//=================================================