Understanding on its attenuation and contrast of images formed

Understanding methods used to image the human body Short essay on medical imaging(attenuation and construct)Lab experiment 1: using sunlight to model x-rayLab experiment 2: how to improve image sharpness and intensity Partner: RitaDate: 6/10/17ABSTRACT      The purpose of this experiment is to investigate the behaviour of x-rays using sunlight. Focusing on its attenuation and contrast of images formed as light passes or deflects through various objects of different densities thereby modelling the use of x-rays as a part of doctor’s facilities to create photos of bones which can be checked for breaks or cracks as well as its accompanying properties that allows its rays enter less thick issue, for example, skin and body tissues (however not bone). Light rays leave a picture on photographic paper as a result andMore thick zones, for example, bone, were represented by solid objects e.g coin which permit less Rays through thus seem paler on X-ray pictures Less thick zones, for example, skin and many tissues, were represented by transparent objects like glass, which permits more rays however.In conclusion, the ability for absorption of each object is dependent on its hardness or density.       The 2nd experiment was to give us a better understanding of how to manipulate the sharpness of the image. In regard to both experiment we have to consider the attenuation and contrast of the images given the different light sourcesINTRODUCTION The objective of the first experiment was to model the attenuation and contrast of X-ray using sunlight, plain paper, transparent glass and solid objects which represented the bones in the body. The plain paper was treated with potassium chloride and silver nitrate which left a photo-reactive white participate that produced silver/grey colour when exposed to sun light. The aim of the 2nd experiment was to improve the sharpness of the image using a power-pack, bulb box, collimator grid and plain paper. We switched positions of the grid, measured and recorded the distance and angles between beams to see how the distances of the collimator grid from the light source influences the sharpness and contrast of the light raysEXPERIMENT 1Aim: to model x-ray using sunlight Materials • Plain paper • Photographic paper (paper treated with silver chloride)• Solid objects: coin (circular 20g masses)• Translucent shapes of varying shades (square, triangle)• Light source: sun, ultraviolet raysMETHOD A plain A3 paper was treated with potassium chloride and silver nitrate to create a photographic paper and the various objects were laid on the paper and left by the window seal to absorb sunlight in-order to model the X-ray image of each objectRESULTS EXPERIMENT 2Aim: to improve the sharpness of imageMaterials • Power pack• Bulb block• Collimator grid(3 slides)• Plain A3 paper METHOD Electric bulb was fixed to a block with collimator grids  which opposes the scattering of light rays, and connected to a power source. Each grid were of different distances from the light source and the distances were recorded along side angles of light rays RESULTS3cm 15 degrees 7cm 10 degrees 10cm 7.5 degreesOBSERVATION While the slide collimator grid was 3cm away from the light source, the rays of light were brighter and scattered and were of smaller angles. While the grid was 7cm away from the light source it produced a more intense and narrow rays which are parallel of in smaller beams. At 10cm away from the light source, light rays became even more narrower, more focused and shadows were casted on the plain sheetsDISCUSSION Light rays leave a picture on photographic paper as a result andMore thick zones, for example, bone, were represented by solid objects e.g coin which permit less Rays through thus seem paler on X-ray pictures Less thick zones, for example, skin and many tissues, were represented by transparent objects like glass, which permits more rays however. Attenuation: more dense solid objects had higher attenuation ability there by reducing the intensity of raysContrast: the difference in attenuation of each materials provided gives the contrast of the imageCollimation:  collimation was achieved using the collimator grid for the narrowing and alignment of the light rays for gaining a more contrast and sharper imageCONCLUSION In conclusion, the ability for absorption of each object is dependent on  its attenuation. The attenuation of objects  and contrast of the images also depends of its distance from the light source. The farther the object is from the light source, the more contrast its image will bePRINCIPLES OF IMAGING TECHNIQUES X-Ray: tubes accelerate electrons into metals and create photons through sudden deceleration. Isotopes such as Radium emit neutral rays. X-rays posses a wavelength between 0.01 and 10 nanometer.its a straight forward procedure that provides high contrast images of bones and excellent tissue interface definition but tissues types are not well defined and uses ionic radiation which could damage tissues ULTRA-SOUND:High energy phonons particles of sound are passed into the body and their echos are listened out for. Echos are produced at tissue interfaces. Time taken is related to the depth of tissue interface and sound reflected is related to the acoustic impedance Z, of the tissues passed through. This method is doesn’t require ionising energy so it’s safer on tissues, produces high contrast and can measure blood flow velocity but images are sometimes hard to analyse and gives no attenuation coefficient of tissues DOPPLER IMAGING: involves Doppler shift which uses change in frequency to measure blood flow velocity FD = FO (v/c) also involves Absorption, scattering, refraction, diffraction and resonance. Doppler imaging is useful for identifying abnormal blood flow, real time image display and providing clearer images and information about blood flow but displaying high speed of blood flow could result to frequency distortion and could affect the whole structure of blood flow condition if not handled properly MAGNETIC RESONANCE: particles with a non-zero spin act like magnets and align or anti-align their spin with external magnetic field. Changing from one state to another requires the absorption or emission of a photon at the frequency of the particle. When illuminated by photons of the right energy, particles will resonate, changing and emitting radio waves. This method produces high resolution images, clear contrast in tissue type and small changes are detectable but its expensive to run due to use of helium and requires very high electric current to runRADIOACTIVITY: Radionuclides, radioactive isotopes, radioisotopes all mean the same. They can be naturally occurring isotopes or artificially created isotopes. Example of the artificial radionuclide is the production of phosphorus 30 through collision of aluminium 27 with an alpha particle. Medical radioisotopes are produced in the radionuclide generator. This method is useful for tracing densities and activities of bone, blood and is also quick and easy to administer but it’s images are of low resolution, it’s not suitable for certain groups e.g pregnant women and it could be so though handling radioactive materials.COMPUTER AIDED TOMOGRAPHY: x-ray slides are taken of the patient from many angles and analysed to produce a 3D image which is of higher resolution and contrast than normal x-rays. CAT provides rapid acquisition of data, and accurate 3 dimension data including attenuation information but also involves high amount of ionisation radiation REFERENCESNotes from class

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