Mutiple choice nuclear medicine question

[Derek1997]

Homework Statement

Why does PET scanner use positron emitters?
1-positrons have more penetrating power than electrons
2-positron emitting isotopes are cheap and widely available
3-the location of emission can be located better because a pair of gamma rays get emitted from the body
4-positron radiation is more highly absorbed by cancer tumours, providing contrast in images
one or more can be correct.

Homework Equations

The Attempt at a Solution

Well I believe it should 3 be the correct solution. But I'm not entirely sure.[/B]

 

[kuruman]

Reason it out. What is the goal of a PET scan? How is that goal achieved? Which of the choices you are given best fits your answer to my previous two questions/

 

[Derek1997]

I guess it's 1,3 and 4 according to your questions.

 

[kuruman]

I guess it's 1,3 and 4 according to your questions.

But you didn't answer my questions
1. What is the goal of a PET scan?
2. How is that goal achieved?
Then we will see how your answers fit the choices. One more thing, is this supposed to be a multiple-choice question (one answer only) or a multiple answer question? I am asking because you provide three answers.

 

[Derek1997]

multiple answer

 

[Derek1997]

goal is to picture stuff in side body, the positoron would be injected to humans body, react with electron as it's more electron anti-particle annihilate both and emitting a pair of beta protons. Now using ring detector, it would be able to deterct protons, hence loacalising the emission. Image recreated using 3D map and hence image is created.

 

[kuruman]

multiple answer

OK, but one more time
1. What is the goal of a PET scan?
2. How is that goal achieved?

 

[Derek1997]

I said that tho

 

[kuruman]

I said that tho

Sorry, I must have posted my answer before I saw yours.

goal is to picture stuff in side body, the positoron would be injected to humans body, react with electron as it's more electron anti-particle annihilate both and emitting a pair of beta protons. Now using ring detector, it would be able to deterct protons, hence loacalising the emission. Image recreated using 3D map and hence image is created.

When you have electron-positron annihilation what is emitted is gamma-rays, not "beta protons". The ring detectors detect gamma rays.
You are right in saying that the goal is to localize the emission. How do you think the point of emission is localized from the emitted pair of gamma rays? Answer this and then we will check out the four possible answers.

 

[Derek1997]

ring detect pair of gama rays, thus detectors all around the ring would detect both photons, thus, localising the point of emission along that line between points where two photons were detected. Dude ik it's not 3 because positrons are not cheap. is it 1,3 and 4??