Contrast media can be defined as a chemical substance either solution or gases that is used in skiagraphy to heighten the visual image of an internal organic structure construction including the anatomical portion of internal organ or soft tissue to that is hard to visualise and distinguish by non-contrast movie. By the use of contrast, many of organic structure ‘s organ and tissues can be demonstrated. Contrast besides enhances the effectivity of many radiology processs. Different tissues or organ will perforate different grade or degree of x-ray beam. The grounds on contrast media being used include the thickness of the country that being studied or examined in the organic structure and the denseness of the constructions that want to be examined. Contrast media is used because soft tissues are hard to show and distinguish from cadaverous portion of the organic structure by doing the internal construction of organic structure ( organ or soft tissues ) opaque on X ray. So, the movie that is produced will clearly be showing the constructions. Contrast media can be categorized as a drug because the substance in contrast media can be absorbed by organic structure and may impact a physiological response. Contrast media besides called as contrast agents and widely used in radiological scrutinies such as in MRI ( Magnetic Resonance Inve ) and in computed imaging ( CT ) .
There are two types of contrast media which are positive agents of contrast media and negative agents of contrast media. Positive agents of contrast media is used to increase denseness difference by doing the constructions ( portion to be examined ) can be seen opaque or white country on the movie. Positive contrast media can be classified as I based and non-iodine based. In medical imagination, I based are normally used in Angiography which is for arterial probe, Venography which is for venous probe, Invalidating Cystourethrogram ( VCUG ) , Hysterosalphinogiogram ( HSG ) , and Intravenous Urography ( IVU ) . Iodine based has high atomic figure that enhance the ability to absorb most of the x-ray and supply good contrast between the interested country and the environing tissues. The illustration of positive contrast agents that hve high atomic figure are Ba ; which have 54 as the figure of atom in the Ba compound and I ; which has 53 as the figure of atom in the I compound. So, for these instances ( Angiography, Venography, VCUG, HSG and IVU ) , contrast media is given intravenously by inserted the contrast agent substance into the blood vas by injection.
Non-iodine based of positive contrast media such as Ba ( which normally be used in medical imagination ) , besides same as I based of contrast media in footings of contrast quality. Non-iodine based of contrast media can besides give a good contrast to the construction that being examined every bit good as to the movie produced. Therefore, in medical imagination, non-iodine based ( Ba ) is most normally used for GI ( GI ) surveies particularly for big intestine ( big bowel ) probe, esophageal probe, tummy probe every bit good as little intestine ( little bowel ) probe. The Ba solution will be prepared by thining the Ba substances with the H2O. This besides helps to bring forth lower denseness of Ba solution. Different types of GI scrutiny need different readying of Ba with different belongingss. For esophageal probe, the Ba readying that is used is barium sup ( BaS ) while for the tummy probe ( to show the tummy and the deudonem ) , the Ba readying that is used is barium repast ( BaM ) . In the other manus, Ba clyster ( BaE ) is prepared for big bowel ( colon ) probe and Ba repast follow-through ( BaM + FT ) is prepared to show little bowel from the deudonem to the ileo cecal. Barium substances are suited to be used in GI surveies because it can non be absorbed by the organic structure unless the patient have suspected in pierced tummy or bowel or any other portion in the GI piece of land ( GI Tract ) . For this instances ( GI surveies ) , contrast media is given either orally ; which is through oral cavity or rectally ; which is through rectum depends on the radiotherapist or radiographer.
The other type of contrast media which is negative agent of contrast media is specifically known as gases. The gases that are listed in the negative agents of contrast media are air, O and C dioxide. In fact, these negative agents are readily available environment us besides the monetary value is excessively inexpensive. Carbon dioxide is the most common used in medical imagination as a contrast media besides the use of other negative contrast media which is O. The negative contrast agents are used to diminish organ denseness to bring forth contrast on the constructions ( portion to be examined ) and the movie produced. So, the movie ( radiogram ) obtained by utilizing this negative contrast agents ( air, O or C dioxide ) will look black or darker. Mostly carbon dioxide of negative contrast media is used pairly with the Ba in the use of contrast media scrutiny to acquire the ‘double contrast ‘ consequence in the process every bit good as addition the quality of movie radiogram. Oxygen is non the best preferred pick in executing the dual contrast because O is the chief factor to bring on a fire hazard to the patient.
The most standards or factors that must be take into consideration for radiotherapist or radiographer in choice of contrast media substances are the history of allergic of the patient to any contrast media substance, the imagination machine that will be used to execute the radiological scrutiny because the type of contrast agents injection varies with the type of imaging machine, drugs or medical specialty used and the type of group of the patients. Other than that, non-toxic contrast, easy to be removed or excreted from the organic structure and inexpensive in monetary value besides includes in the consideration ‘s factor to take an ideal contrast media. The groups of patient include, diabetic patient, wheezing, infant, aged patient, patient with nephritic damage and patient with cardiac damage. This is to guarantee there is no complication to the patient during or after the process is done. The other standards or factors that are of import in choice of contrast media substances are the ability of contrast substances to blend with the organic structure fluid, the viscousness of the substances which can be defined as the opposition of fluid to flux in the organic structure, the I based readyings ( ionic H2O soluble, non-ionic H2O soluble, greasy agents or agents excreted in the gall ) and the osmolality of the substances which means that concentration of all the atom to fade out in organic structure fluid, type of compound ; which is either monomer or dimer compound and the ionicity of the compound substances ; which is either ionic compound or non-ionic compound. Normally, substances or compounds with non-ionic monomer that have the ability to blend with the organic structure fluid, and besides have low osmolality and viscousness are the best pick by the radiotherapist or the radiographer as the substances for contrast media. Low osmolality is of import to patient as to minimise or cut down the consequence on cardiovascular system, blood-brain barrier and local symptoms such as hurting, heat and esthesis. Low osmolality contrast media besides of import and be used in all painful of arteriographic process because it can cut down or minimise the motion of patient by minimise the patient ‘s uncomfortableness every bit good as cut down the possibility to reiterate the radiogram. For illustration ; iopamidol ( non-ionic monomer ) with low osmolality ( 600-850 mOsm/kg H2O ) and viscousness between 9-10Centipoise ( Cp ) at 37 & A ; deg ; is more preferred than diatrizoate ( ionic monomer ) which has high osmolality ( & A ; gt ; 1500 mOsm/kg H2O ) .Therefore, all the standards and factors are really of import in choice of contrast media particularly the substance with low osmolality.
Contrast media besides have its ain complication or any related complication to the contrast media during of any contrast media scrutiny. Complications may besides be occurred when utilizing contrast media ; either water-soluble contrast media or non-water-soluble contrast media. Every patients with contrast media administered will hold any reactions but the reactions are varies harmonizing to the patients themselves. These because the inauspicious reactions are differ by patients consequently to their ain antibody reactions towards the contrast media. The complications or inauspicious reactions can be classified into mild, moderate and terrible inauspicious reactions.
The mild inauspicious reactions usually do non necessitate intervention but the patient should be monitored and observed carefully for 20-30 proceedingss after the contrast media process for any patterned advance of more terrible reactions that required intervention. This type of reaction is by and large caused by increasing osmolality of the contrast media. The symptoms are nausea, purging, coughing, urticaria ( skin status job ) , esthesis of heat or heat and hurting at the injection site.
The 2nd phase of inauspicious reactions is average phase or the other name is moderate inauspicious reactions. It is suggested to be given a intervention but non an intensive intervention. Furthermore, the symptoms are non instantly looking after the contrast media process. The symptoms includes ; bad emesis, concern, in-between phase of urtications, dyspnoea, mild bronchospasm and abdominal spasms.
The concluding phase of inauspicious reactions of contrast media is the terrible inauspicious reactions. The patient with terrible symptoms must acquire the dangerous interventions and intensive attention is necessary for this patient. The symptoms for this terrible inauspicious reaction are moderate or terrible bronchospasm, moderate or terrible laryngeal hydrops, anaphylactoid dazes and cardiac apprehension. The delayed clip to acquire the immediate interventions or reach the doctors for these terrible symptoms can take to decease.
Although contrast media has many good in medical imagination, radiotherapist, radiographer and the clinical staff must maintain concern about the patient before, during and after the contrast media processs. The volume and the description of contrast media and the drugs administered that are used are recorded and maintain as history of patient ‘s intervention. Last, guarantee there is no side consequence on patient ‘s status and guarantee the patient ‘s vision has no blurring before the patient can go forth the x-ray section. If there are other serious reactions due to the effects of contrast agent, the patients must instantly necessitate to see their doctors for immediate intervention.