The coil is the part of the machine that will actually make it work, by giving of a radio frequency. The scanner uses hydrogen atoms to tell the difference between different tissues. MRI scanners will use ‘spin’ which is a property in the machine which can tell the differences between tissues, such as fat, tendons, and muscle. Once the MRI scanner is turned on and the patient is in ready to be scanned the nuclei of the hydrogen atoms in the machine can spin in one of two different directions. The hydrogen atom nuclei can change the direction of spin to the opposite direction.
In the case of MRI it would allow for doctors to better locate uncommon cell growths and tumors. Sections of the patient’s body are exposed to a very strong magnetic field, then a radiofrequency pulse is applied causing some atoms even that of the contrast agent to spin and then relax after the pulse stops. The scanner would detect the energy emitted by the relaxation and
1. Explain how medical magnetic resonance imaging (MRI) exploits the magnetic properties of the nucleus. MRI’s rotate the nucleus of an atom, producing a magnetic field. During a MRI, a person is placed between the poles of a strong magnet. The magnetic field permeates the tissue and causes the nucleus scale magnets in the tissues to rotate.
Its two main functions are data link layer’s connection to the network layer above it done by the sub-layer (logic layer Control (LLC)) and second function being done by the sub-layer MAC- Media access control which controls the physical hardware. Question 10: Describe four types of noise. Which is likely to pose the greatest problem to network managers? Four types of noise; White noise; is the background hiss or static on radios and telephones) is caused by the thermal agitation of electrons and therefore is inescapable. Impulse noise; is heard as a click or a crackling noise and can last as long as 1/100 of a second.
In this lab I hope to determine what happens to the period of the vibration, due to the retarding force. Hypothesis: When an object has bigger mass it tends to slow down faster compared to a an object with a smaller mass. In this lab I believe that the bigger retarding fore will make the period of the vibration decrease faster than the small retarding force. Variables: IV: Period Of vibration DV: Retarding force CV: Type of paper, measuring device, and size of paper UV: pulling the rubber bands at different lengths, human reflex with the cbl, and the wind in room blowing. Procedure: 1.
Among the suspected causes are environmental triggers, genetic predisposition, dietary triggers and physiological triggers such as menstruation. An internal or external trigger sets the process in motion. It is possible that the nervous system reacts to the trigger by conducting electrical activity that spreads across the brain. This electrical activity leads to the release of brain chemicals that make blood vessels swell and become leaky. Scientists think that it is this inflammatory process that causes the pain and other symptoms of a migraine headache.
When a person lies in an MRI scanner, protons in the brain align with the strong main magnetic field of the scanner. A second magnetic field, which oscillates at radio frequencies, is applied perpendicular to the main field and pulsed in order to push a proportion of the protons out of alignment with the main magnetic field. The protons then drift back into alignment with the strong magnetic field, emitting a radiofrequency as they do so, which can be detected. Protons realign at different speeds in different body tissues, thus enabling distinct structures to be revealed. Amyloid deposits have been mapped utilising molecular targeting vectors labelled with contrast agents to selectively enhance the signal from amyloid plaques (Wadghiri et al., 2004).
Intrathecal drugs is a rare way of administering drug directly into the CNS but there is a higher risk for systemic toxicity. Drugs administered topically is applied on a local area (skin). Transdermal is also applied on the skin via a patch which is used for a sustained delivery of drugs. All these are different routes for administering drugs but they all are different in their absorption rate. The order is as follows: Inhalation = IV > IP > IM > SC > PO > Rectal Refernces: Katzung, Basic and Clincal Pharmacology, 12th edition, McGraw Hill Publisher, Pharmacokinetics and Pharmacodynamics pg 37-53 Harvey, Pharmacology, 5th edition, Wolter Kluwer Publisher, Pharmacokinetics
MRI scans involve the use of a magnetic field that causes the atoms of the brain to change their alignment when the magnet is on and emit various radio signals when the magnet is turned off, a detector reads the signals and uses them to map the structure of the brain. PET scans involve administering slightly radioactive glucose into the patient, the most active areas of the brain use glucose and radiation detectors can see the radioactive areas so building up a picture of the activity in the brain, the scans take between 10 and 40 minutes to complete and are painless. PET scans reveal chemical information that is not available with other imaging techniques. This means that it can distinguish between beign and malignant tumours e.g. PET scans can also show the brain in action which is useful for psychological research.
MRI can give detailed pictures of internal structures by using radio frequencies with an MRI scanner to produce an electromagnetic field aligning water molecules and consequently producing an image. The strengths of MRI imaging are that it shows how blood flows in the brain, and can show circulation problems. It also can be used in early detection of Alzheimer’s disease. The limitations of MRI Imaging are that it is expensive, the images are affected by movement and it cannot establish a cause-effect relationship. Research evidence using MRI Imaging is by Ashtari et al (2009).