When one is considering the production of the gamma photons involved in positron-electron annihilation, we can assume that they are travelling very close to c, the speed of light in a vacuum. On the contrary electrons in your body aren’t travelling very close to c, and the positrons are not able to be released at this speed, so one can consider the speed, and hence momentum, of the electrons as negligible when one monitors the photons produced as a result.
This means that in order to conserve linear momentum, the photons will be released at an angle of very slightly under 180o from each other. As the body part is inserted into a circle of scanners, one is able to monitor the activity of the photon, and by measuring the amount by which the wavelength of the photon has decayed at each end and can find the exact point at which the decay occurred, allowing us to see the volume of blood distributed to each area around the body.
Antimatter, contrary to popular belief, is just simply ordinary matter with a line over it! The difference between matter and antimatter has puzzled scientists, and all they know is that for each of the elementary particles in the matter classification, there exists a reverse, or antiparticle to that. One possible theorem was that which Feynman suggested, namely that antimatter is merely matter going backwards in time. The charge is opposite but apart from that, they are almost identical.
Why this type of matter over the other type has survived is an interesting question which has stumped physicists and, indeed, there is still no answer! What physicists do know, however, is the vast amounts of energy that could be used were antimatter harnessed properly. Its production, through the beta-plus decay process or pair production of a photon is uncontrolled, as is the annihilation energy, but could it be harnessed then there would be significant advances in physics.
Is it worth creating antimatter? Is it worth creating antimatter now? Clearly, no. Although the antimatter is a very useful substance, it is simply worth too much to be efficient. When it was first created, less than one trillionth of a gram was seen as remarkable, and when creating this amount of the material is abnormal or strange, then there is little point in investing the money or energy into created a large amount of antimatter using the techniques we have at the moment.
Although antimatter could be a valid energy production source (see Figure 13 for evidence of this,) first a valid method of creating or harnessing the antimatter fuel must be created. Is it worth funding research into antimatter? However, I would definitely advocate the research into antimatter. During the cold war, when scientific progress was much enhanced, antimatter was being vehemently researched because scientists knew of its sheer energy density, and there is clearly every reason to attempt to harness it.
Although some people may not agree with the sentiments behind all of the motives to creating this new matter, it is clear that it will do more good than evil. Nuclear energy has had a large amount of good and the energy that could be produced outweighs the potential evil that it could be used to create weaponry. All science could be used rightly, or wrongly and funding research into antimatter allows the use of it in such brilliant scientific schemes such as solving the world’s renewable energy crisis; medical imaging or even just furthering research into astrophysics.