Role And Purpose Of Contrast Media Biology Essay

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Purpose of do contrast media are contrast media used to observe any substance that show an organ or structure more visible than is possible without its addition. To allows visualization of structures that can not be seen well or at all under normal circumstances. The intensity of x-ray poton in x-ray tube are differaence when penetrating the tissue of body. The show clearly of image radiograph of film, we must give contrast media through our body that our body with low contrast. Contrast media is needed because soft tissue has a low absorption and interaction ratio that is absorption is dependent on an atomic number, atomic density, electron density, part thickness of tissue or organ, K-shell binding energy (K-edge) and 5 materials seen on a radiograph are gas/air, fat, soft tissue (muscle or organs), bone and metals. Contrast of tissue or organ depend on atomic of tissue or organ (high atomic of tissue or organ will attenuate more radiation and give high contrast image to tissue or organ). Beside that, contrast of tissue or organ depend on density of tissue or organ (more dense of tissue/organ will attenuate more radiation and give high contrast image to tissue or organ).The thickness of tissue or organ also will cause the thicker of the part of tissue or organ will attenuate more radiation and give high contrast image to tissue/organ. Atomic Number of contrast media for Fat is 6.46, for water is 7.51, for muscle are 7.64 and for bone is 12.31. Brief History of contrast media is in 1897, first reported GI contrast study performed by Bismuth. In 1910, Barium Sulphate are used because safer. In 1920, Sodium Iodide is used to treat Syphilis. Iodine was found to be radiopaque to x-rays. Bases of all modern contrast agents. In 1927, first reported IVU with iodized organic salts (Uroselectan) Requirements of a Contrast Agent is it easy to administer, no toxicity, stable compound and will not dissociate into toxic ions. Beside that, when injected the contrast media. Contrast media will concentrate in areas required producing good contrast. The agent's physical features allow the organ to be properly demonstrated (non-flocculating). Example Barium coating of the stomach in the presence of an acid environment. The agent should have rapid elimination. The agent should not be carcinogenic. The agent should have a viscosity appropriate to the patient when introduced. The agent should cause minimal distress to the patient when introduced. And lastly the agent should be cost-effective. Methods of administration of contrast media are orally, rectally, by intravenously by injection and infusion, mechanically are filling of a body cavity or potential space and by Intra-muscularly. Examples of areas where contrast agents are used are in Arteriography in mesenteric arteries, Angiography (DSA) in cardiology, Venography (replaced by ultrasound- Doppler), IVU (Intravenous Urography), Fluoroscopy are used in alimentary tract, hyserosalpingography, sialography, dacrocystography. Besides that, the ultrasound of liver and kidney, Myelography are replaced by MRI and lastly for the Arthrography of knee joints. Have Negative Contrast Agents. The Examples of negative contrast agent are air, CO2 and O2. Negative contrast agents are used in trauma and pathology that have perforation, surgical emphysema and Fat Pad signs. Besides that, negative contrast agents perform to reduce the atomic number of the area to be demonstrated. These types of contrast media will have little attenuation of the x-ray beam. Positive Contrast Agent. The examples of positive contrast agent are barium based (Baritop) and Iodine based agents divide into 2 types that is ionic agent and non-ionic agent. That is the the water soluble (Niopam) and non soluble (Lipiodol, Myodol). The positive contrast of the agents increase the atomic number of the area to be demonstrated in relation to the surrounding tissue. X-rays considerably attenuate these types of contrast agents. Iodine based contrast agents. Approximately 90% of all contrast media used in x-ray imaging in termed intravascular or general contrast media. The physical properties of the iodine based contrast media include the ions or particles associated with the chemical breakdown of the contrast media when it enters a solution, the number & size of the iodine molecules & the number size of the molecules of any chemical additive. The chemical composition of ionic & non-ionic contrast media contains iodine. On its own, iodine is unsuitable as a contrast agent because it's toxic. Achieved by basing the molecule on the benzene ring & replacing the carbon atoms at set points with iodine to produce tri-iodinated benzoic rings. Iodine based contrast medium agent used for Angiography (arterial investigation) are IVU (Intravenous Uroghraphy). Non-iodine based contrast medium agent used for barium studies that is Barium Enema (large bowel investigation). Ionic Contrast Agents.. An ionic contrast agent has approximately five times of the osmolarity of human plasma (that is called hyperosmolar) The iodine atoms must give provide the attenuation properties. Furthermore, the additional chemical groups determine the properties of the contrast agent, its example are the solubility, the toxicity, the viscosity and also the osmolarity. For the typical Ionic contrast agents include the Conray 280, conray 325 & the conray 420 (The number of conray refers to the iodine concentration in mg/ml-1). Contrast Agents.. An ionic c human plasma (that is called hyperosmolar) The iodine atoms must give provide the attenuation properties. For the contrast agents of ionic Dimer has the osmolarity for contrast agent has approximately five times of the osmolarity of human plasma (that is called hyperosmolar) The iodine atoms must give provide the attenuation properties. For the contrast agents of ionic Dimer has the osmolarity for the solution that measurement for the volume of molecules and also the particles for the solution dilute in water. If cells in an organ are surrounded by a solution of greater osmolarity than the cellular fluid, water will leave the cells which will ultimately shrink & distort, sometimes being disrupted completely (Dawson 1984). Fluid shifts can have a devastating effect on patients. In the thickness of contrast agent are depend on viscosity of contrast agent flow with a resistance. The thickness of the contrast agent is related to the concentration, the size of the molecules in a specific contrast agent & the temperature of the contrast agent. The viscosity affects the rate that the contrast media can be injected. Non-Ionic contrast media are often referred to as "low osmolar". The contrast media with non-ionic will not dilute with the particles charged solutions are enter. In every iodine molecules of three that solution in the non-ionic agent, will produced one neutral molecule. 3:1 compounds of non-ionic contrast agent are recommended. More safer used the non-ionic contrast agent than ionic contrast agent but non-ionic contrast agent high cost. . In every iodine molecules of three that solution in the non-ionic agent, will produced one neutral molecule. 3:1 compounds of non-ionic contrast agent are recommended. More The non-ionizing radicals (NIR) are Non-ionic contrast agents replace to the sodium side chains. Double contrast agents are incorporates the use of both positive & negative contrast media. Example during a double contrast Barium enema examination. (Co2 + BaSo4 equal to Double Contrast). Double contrast studies with Barium are air used with other contrast agents for better to see internal structures and after that iodine will dilute by air in the bladder. Used Barium Sulphate because Barium Sulphate have high atomic number (Z=56), non-toxic, relatively cheap and inert. Example of barium based contrast agents are used in barium swallow, barium meal, barium follow through, small bowel enema and barium enema. Barium has 2 types thick are used for double contrast and thin are used for single contrast. Palatability of Barium are chalky taste with barium sulphate and water mixture, contain a flavoring agent, sweetness, for differentiate the taste unpleasant with suspensions thicker and thinner can be used for more commercial procedure that hve carboxymethyl cellulose (theRaybar, the Barosperse) and contain frequent solution to avoid precipitation for the barium suspension for used to normal small bowel. single contrast. Palatability of Barium are chalky taste with barium sulphate and water mixture, contain a flavoring agent, sweetness, for differentiate the taste unpleasant with suspensions The examination with double contrast are used want to get examination of double contrast for the stomach example air and carbon dioxide gas that must introduced. Furthermore, more radiographer are try to used efficient tablets likes (the sodium bicarbonate, the tartaric acid and the calcium carbonate) and also give reaction of chemical for the gastric contents to form the carbon dioxide. Pharmacological agents are Buscopan, Glucagon and Maxalon. Buscopan & Glucagons are both used to relax smooth muscle (Glucagon more potential & can be used on patients with glaucoma & cardiovascular disease). Useful in barium enema examinations. Maxalon increases gastric peristalsis (useful in follow through examinations). Patient preparation are patient must tell the doctor, if patient have history that she might be pregnant, have had recent abdominal surgeries and have any medical illnesses such as bronchial asthma heart failure hypertension. For diabetic patient. Patients who should use low osmolar and/or non-ionic contrast media are infants and small children. For those patient with renal and cardiac failure. Poorly hydrated the patients. Then for those patient who have multiple myeloma, diabetes mellitus and sickle cell anaemia. That patient who have had a previous severe anaphylactoid or allergic reactions to a conventional contrast media or those who have strong allergic history. Contrast media for adult dose for patient weight 70 kg must give contrast media that low must less than 12g Iodine. Medium contrast media are 12g to 30g Iodine and for high contrast media must more than 30g Iodine. A suitable dose is 60ml Conray 420, Niopam 370 or equivalent. The maximum dose is 0.6g Iodine per kg. Contrast media for paediatric dose are using contrast media of strength with 300 mg Iodine per ml. Up to 12 kg with1.5 ml per kg. 13 to 54 kg contrast media for 18 ml per kg. More than 54 kg for use adult dose of contrast media. Room equipment and room preparation are must prepared the radiographic room. Make sure do correct type and correct amount of contrast media drawn up in an appropriate syringes. Must sterile needles including a 18G / 19G butterfly needle to avoid infection. Used alcohol sponge or wipes in radiographic room during examination. Used lead markers including L (left) and R (right) and time-interval and body-position markers to differentiate position of patient. Radiographic room must have emergency trolley. And also have compression set. The care must provide after procedure to patient are make sure patient understands clearly that instructions preparation after finished procedure examination,patient must to normal diet and drink to cleanliness the area that used contrast. For diabetic patient who take Glucophage (an oral hypoglycemic medication), patient must drink or eat the contrast before the radiographic examination but don't taking high food for 48 hours at least when after examination done. Patient always tell to the doctor that ordered the contrast agent like Glucophage that to find out when it is safe to taking after that. Side-effect of contrast media are in clinical purposes the side-effect is divide into three categories that is minor (flushing, nausea, vomiting, priritis, mild rash and arm pain), for moderate categories (more severe urticaria, facial oedema, hypotension, and bronchospasm) and last categories are severe (hypotensive shock, laryngeal oedema, convulsions,respiratory and cardiac arrest. Side-effect for infant is introduction of hyperosmolar fluid into the bodies of very young children can cause problems of fluid balance. For the elderly also cause problems of fluid balance. Beside that, contrast medium also can give effect to the diabetes patient, patient with cardiac impairment, patient with renal impairment; patient has asthma, patient who has previously reacted adversely to a contrast medium, patient with a history of allergy and patients who are unduly anxious.

Two types of Radiographic "Contrast"

Ionic Dimer contrast agents

Non-Ionic contrast media

Film of Double contrast studies with Barium

Barium Enema (room air mixed with Barium, Ba)

Upper Gastrointestinal (gas "fizzies"used)

Barium Sulphate

EXAMPLE OF CONTRAST MEDIA

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