Whilst the ethics of post mortems can be retained, such a procedure after death is outlawed or disapproved by many religions. Judaism and Islam forbid them, whilst others will allow them to occur under special circumstances. However, if the subject of the investigation belongs to a religion that decrees post mortem as forbidden, nothing can be done to examine the brain in a technique like post mortem investigations, no matter how much the information is needed for research. Furthermore, if the cause of the research is brain damage, examining the brain itself may not bring about a pinpoint conclusion as to which area is responsible. Alternatively, the rarity of the affliction needed to be studied may affect how many brains there are able to use- not everyone will have this affliction, and an even smaller percentage will adhere to post mortem examinations after death.
As technology and technique in cortical specialisation investigations have improved, a greater array of scanning methods have been discovered; all with different benefits and disadvantages. Such scan types include Computerised Axial Tomography (CAT), Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI). CAT scans comprise of sending a thin X-ray beam, at different angles, through the brain, and measuring how much radiation is absorbed by it.
They produce 3D images that can identify tumours and damaged tissues at a deep level. With PET scans, a small amount of radioactive glucose is injected into the bloodstream, and provides the brain with energy which is then shown onscreen whilst the subject is conscious and performing tasks. MRI scans are more precise than PET or CAT scans. It is a powerful technique where scanners use extremely strong magnetic fields and radio waves, produced to circle the subject whilst they are inside a tunnel.
There are many advantages to scanning methods, which can solve many problems confronting post mortems. CAT scans are especially quick yet accurate, and eliminate the need for invasive methods like post mortems- reducing the issue of ethics that can affect the validity of a post mortem. Socially, it reduces the length of hospitalisation for the patient, and almost eliminates any risk of infection. There is also no limit to the amount of anatomy that can be examined during a CAT scan, and be equally undamaged. Results come about quickly, with a wide spectrum of information. PET scans are relatively new methods of identifying areas of the brain, and allow the examiner to investigate biochemistry non-invasively. It can help detect diseases before they have any effect on the health of the person, and therefore is more effective than other imaging methods.
For example, it has the ability to more closely distinguish between malignant and benign tumours in the brain, and has no risk of infection. MRI scans are, again, non-invasive and does not use any radiation (that could potentially cause harm to the patient) during scanning. MRI also enables the discovery of abnormalities that might be obscured by bone with other imaging methods. With CAT scans however, there is a small risk of the X-rays harming the foetus of any subject that is pregnant, and the same is considered for children unless absolutely necessary. CAT scans also require breath holding which some patients cannot manage.
High doses of radiation are involved in CT scanning; a chest CT scan is equivalent to 350 chest X-rays; CT abdomen to 400 chest X-rays and CT pulmonary angiography 750 chest X-rays- this, when used on the brain, can have huge detrimental effects. PET scans also have disadvantages- like MRI scans, it requires use of a tunnel, so claustrophobia can be an issue with patients.
Also, there are health risks that are similar to the CAT scan; in general, the radiation from a typical PET scan is equivalent to about 3 to 5 times as much as a person would receive in 1 year from the naturally occurring background radiation exposure. Many do not like the closure of being in the tunnel as part of MRI equipment. If sedation is therefore used, there are risks of excessive sedation. A technologist or nurse monitors vital signs to minimize this risk, but is subject to human error. People with pacemakers cannot have MRIs and some people who are morbidly obese cannot fit in into an MRI system. Patients are given earplugs or stereo headphones to muffle the noise caused by the rising electrical current in the wires of the gradient magnets being opposed by the main magnetic field. The stronger the main field, the louder the gradient noise.
In conclusion, both methods of investigating cortical specialisation have both advantages and disadvantages. Scanning techniques has less ethical risks than post mortems, and confronted with fewer related difficulties. However, post mortems are done after death (therefore, no risk of infection) and are as accurate as one can get. Scans are the same, but are very expensive, and many use radiation which can build up and cause many health issues. One isn’t necessarily more effective than the other, but are used in separate situations and meet different needs.