QUALITY ASSURANCE AND QUALITY CONTROL 1.pdf

QUALITY ASSURANCE AND QUALITY CONTROL RTE-020 ACCESSORY EQUIPMENT Collimators The collimator, sometimes referred to as the light beam diaphragm (LBD), provides the radiograoher with an easy to use, accurate, method of controlling the size of the X- ray field and placing it over...

QUALITY ASSURANCE AND QUALITY CONTROL RTE-020 ACCESSORY EQUIPMENT Collimators The collimator, sometimes referred to as the light beam diaphragm (LBD), provides the radiograoher with an easy to use, accurate, method of controlling the size of the X- ray field and placing it over the area of interest, thus reducing the radiation dose to the patient and improving the quality of the image The collimator receives much use and is vulnerable to knocks, often resulting in inaccuracy of the light beam/X- ray beam coincidence, blown light bulbs, electrical and mechanical problems. Collimators Visual Inspection – Light timer – Rotation – Timer switch – Stability – Cables – Knobs for shutter control – Plugs – Accuracy of shutter setting – Light bulb scales – Light/X-ray beam alignment – Shutter chain drive – Shutters – Housing – Window Collimator Accuracy of Scales Test – Inaccuracy of scales may – Not everyone uses the lead to inaccurate aperture size scales on the collimation collimator to set the – Frequency of test aperture size, it is being every 6 months more common practive to – Equipment required use visual assessment of Collimator to be tested the light field size. However 100 cm rule if staff do practive this method, it is advisable to make sure that the scales are accurate Collimator Accuracy of Scales Test – Evaluation – Method light area measured should be the same as the setting on Set 100cm focus to tabletop collimator distance Using the 100cm FFD (SID) – Action scale on the collimator, set If settings are not accurate vaous aperture sizes with the and the solution is not a light on and measure the simple one, call an X-ray resultant light areas at table engineer. top level File a report Compare with setting on the collimator Collimator Changing a light bulb – Frequency – A light bulb can fail at As necessary anytime without warning. It – Equipment required is important then, to have Suitable light bulb the correct spare bulb Cloth or tissue readily available. Screwdriver – Staff should be capable of replacing a faulty bulb. DO NOT ATTEMPT THIS UNLESS YOU HAVE HAD ADEQUATE INSTRUCTION. If unsure, call an electrician. Collimator Changing a light bulb If the bulb is of quartz type, ensure that it is not handled – Method with bare fingers, as body oil Switch off the power. on the bulb will shorten its life Remove relevant collimator Replace housing and tighten housing screws Check the spare is the correct Test type Ensure that the spare bulb is Before removing the old bulb, replaced as soon as possible check to see if the replacement bulb must be fitted a specific way around Replace faulty bulb with a new one Collimator Light beam/X-ray beam – Should either the mirror or alignment test the light bulb be dislodged, then errors in collimation – the purpose of the light in a could occur, resulting in collimator is to allow more areas of interes being accurate collimation of the excluded from the field, or X-ray beam. The light must, too large an area being therefore, coincide with the irradiated. X-ray beam. The light beam relies on the accurate positioning of the light bulb and angled mirror inside the collimator. Collimator Light beam/X-ray beam Lead marker or ninth coins alignment test – Method Make sure that the table is – Frequency of test level and the central ray at 90 every 6 months degrees to the tabletop as necessary Place a loaded cassette on – Equipment required the tabletop face up One 24x30cm loaded Set a FFD (SID) at 100cm cassette Switch on the collimator light Alignment test tool. Centre to the middle of the Commercially made test tools cassette are available, but simple alternative is to use eight coins or four paper clips Collimator Light beam/X-ray beam Place the lead marker within one corner of the light field so alignment test that the film can be related to – Method the light/X-ray field and hence Collimate to within the edge the collimator shutters. of the cassette, leaving a 3cm Make an exposure sufficient border all around, that is to blacken the film outside the light field Process the film Place the coins in pairs, so – Alternative method that, where the coins touch, Use four paper clips, each coincides with the edge of the bent to form right angels light area Place paper clips at corners All four of the border must be of light field marked in this way Collimator Light beam/X-ray beam – Evaluation alignment test For perfect alignment, the light field (where the coins – Note touch) should coincide with Collimators are known to the X-ray field. become less accurate as the The irradiated area must not field size is increased. To be greater than the area check this make two flash covered by the light. exposures on the same film, At 100cm FFD (SID) the following the method irradiated area must not be described above, using more than 10mm smaller than different field sizes, the area covered by the light. remembering to re position This represents a 1% the markers for the second tolerance exposure Collimator Light beam/X-ray beam alignment test – Action If the alignment is unacceptable it must be adjusted Call an X-ray engineer – Note Cones and diaphragms can also be checked using a similar method Collimator Shutter efficiency test – Frequency of test – Closing the shutters in the every 6 months collimator fully should – Equipment needed prevent any radiation from One loaded 24/30cm cassette reaching the film. Useful for – Method testing radiation safety Place the cassette on the when discharging capacitor tabletop face up discharge mobiles or Set a FFD (SID) of 100cm making tube warm up Set an exposure of exposures approximately 80kV and 40mAs Collimator Shutter efficiency test – Evaluation – Method Study the film. If the shutters are efficient the film will not Open one set of shutters fully, have been affected by leaving the other closed radiation Make an exposure – Action Fully close the open shutters and open fully the closed If the shutter are allowing ones radiation to pass, call an X- ray engineer Make another exposure Process the film Cassette and Intensifying Screens Cassettes are light tight Cassettes are easily containers that hold the X- damaged and likely to ray film between the wear, resulting in possible intensifying screens. They light leakage and poor film are available in a range of screen contact. sizes to suit every need. Intensifying screens Intensifying screens deteriorate over time and fluoresce when struck by are easily damaged. radiation, the light emitted Foreign material on their significantly contributing to surface or damage will the blackening effect on create marks on films the film Cassette and Intensifying Screens All cassettes should be All cassettes should be clearly numbered on the marked on the outside, outside. A corresponding identifying the type of number being placed intensifying screens fitted. nside, on the edge of one of the screens, using an indelible marker, where it will not affect the image, but is visible on the radiograph Cassette and Intensifying Screens If different film/screen Both cassettes and combinations are used in screens should be the department, screen inspected and cleaned speed should be clearly regularly. Records must be indicated on the outside of kept of all inspections, the cassette. It is usual for maintenance and manufacturers to supply replacements. appropriate labels with their screens. Cassette and Intensifying Screens Cassette inspection – Evaluation – Frequency of inspection Faulty parts, distortion and inadequate cleanliness must Yearly be attended to As necessary – Action – Equipment required Repair faults or replace Cassettes to be inspected cassette – Method Carry out film/screen contact Inspect test Hinges Clean with damp cloth and Catches wipe dry Casing Keep records of work carried out Cleanliness File report Cassette and Intensifying Screens Light leakage test – Evaluation – Frequency test Black fogging around the edge of the film is an Yearly indication of light leakage as necessary – Action – Equipment required Repair or replace cassette Cassette to be tested File report – Method – Note Load cassette with new film Similar fogging can be Place cassette under birhgt caused by a lid being left off a light for approximately 15 to box of film or the film hopper 30 minutes left open, allowing white light Turn cassette and repeat exposure of the upper edge Process film of the films Cassette and Intensifying Screens Light leakage test – Evaluation – Frequency test Black fogging around the edge of the film is an Yearly indication of light leakage as necessary – Action – Equipment required Repair or replace cassette Cassette to be tested File report – Method – Note Load cassette with new film Similar fogging can be Place cassette under bright caused by a lid being left off a light for approximately 15 to box of film or the film hopper 30 minutes left open, allowing white light Turn cassette and repeat exposure of the upper edge Process film of the films Cassette and Intensifying Screens Instensifying screens – Any damage, deterioration – Most cassettes are fitted or foreign matter will be with a pair of intensifying seen in resultant image. screens and should be used with a double emulsion film. – Blue light emitting screens should be used with blue light sensitive film – Green light emitting screens should be used with green light sensitive films Cassette and Intensifying Screens Instensifying screens Correct number on edge of screen inspection Condition of screen surface – Frequency of inspection – Evaluation Monthly Abrasions – Equipment required Foreign material on surface Screens to be inspected Discolouration (an indication – Method of deterioration) Inspect in bright light Fitted correctly conditions Correct screens Screens firmly fitted Correct screens fitted Cassette and Intensifying Screens Instensifying screens inspection – Action Loose screens should be re- fitted with double sided tape Surface damage or deterioration, which is unacceptable-replace screens Clean if necessary File report Cassette and Intensifying Screens Instensifying screens – Method cleaning Clean in bright light condition Remove all loose dirt with a – Frequency of cleaning soft brush or puffer monthly Apply screen cleaner – Equipment required sparingly with a lint free cloth Soft brush such as a gauze swab Puffer Use circular motion over Lint-free cloth, such as gauze whole surface Screen cleaner (available Finish off with long strokes from manufacturer) or mild from top to bottom soap (not detergent) Do not pour cleaner directly on to the screen Cassette and Intensifying Screens Instensifying screens – Action cleaning If dirt particles or smears remain, re clean – Method If after repeated cleaning, dirt Wipe with dry lint free cloth particles remain decide if they Stand cassette open for 30 are likely to be a problem minutes to dry If they are considered to be a Inspect problem, replace the screens – Evaluation Have all dirt particles been removed? Are there any smears? Cassette and Intensifying Screens Film/screen contact test – Equipment required – If an area of localized Cassette to be tested blurring is detected on a Test tool (box of paper clips or sheet of perforate zinc or radiograph, poor film/screen fine wire mesh, large enough contact should be to cover a 35x43 cm film, with suspected. a square hole, about 10cm – Frequency of test from one edge, approximately 2 to 2cm square. Yearly Lead marker if cassettes do As necessary not have a lead blanked area for patient details. Cassette and Intensifying Screens Film/screen contact test Make an exposure using about 50kV and 6mAs (film – Method density of 1 to 2) Load the cassette to be Process film tested and place it face up on the tabletop – Evaluation Cover the whole of the If a densitometer is available cassettes with the test tool of the film density can be using paper clips, distribute measured at the image evenly created by the hole in the test tool Set a FFD (SID) of 150cm the longer FFD (SID) reduces Inspect the image, looking for geomtry unsharpness areas that look blurred Collimate to cover whole of cassette Cassette and Intensifying Screens Film/screen contact test – Action – Method Repair or replace cassette A noticeable of unsharpness Replace packing could be caused by: Re-est – A damage cassette File a report – Screen packing, deterioration – An air pocket When using a close mesh wire test tool poor film/screen contact areas may also have a higher density. Cassette and Intensifying Screens Film/screen compatibility- – If there are any doubt about colour of light emission the colour compatibility of test. the light emitted by the screens, the following – different types of IS may simple test can be used. emit different light colours – Frequency of test and/or intensities. as necessary – The colour of light emitted by screens must be the – Equipment required same as the colour screens to be tested sensitivity of the film used with them. Chec with your film and screen supplier when is doubt. Cassette and Intensifying Screens Film/screen compatibility- Make an exposure using a relatively high kV and long colour of light emission time, e.g. 80kV and maximum test. time possible – Method Observe the screens during Open the cassette the exposure. Remember to follow normal radiation safety Remove the film rules. Place the open cassette, screen facing up, on the – Evaluation tabletop Note the colour of light given Set FFD (SID) of 100cm and off by the screens collimate to cover the open Note the entensity of the light cassette given off by the screens Reduce room lighting to a Cassette and Intensifying Screens Film/screen compatibility- If the light intensity comparison between pairs of colour of light emission screens is noticeably different, test. check the labelling of your – Action cassettes for screen type and/or carry out the If the colour sensitivity of the intensifying screen film is not the same as the consistency test screen light emission colour, you should change the type Re label the outside of the of film you use so that they cassette if necessary. are compatible. Cassette and Intensifying Screens Intensifying screens – It is therefore necessary to consistency test check the efficiency of all screens periodically in order – the efficiency of screens to achieve consistent tends to deteriorate over results. time – Frequency of test – If you have screens of the Yearly same type, but of differing as required ages, you cannot assume that they will all give the same result. Cassette and Intensifying Screens Intensifying screens Load each cassette to be tested with one strip of film consistency test placed centrally – Method 1 Place the first cassette on the – Equipment required tabletop, face up Step wedge Place the step wedge in the center of the cassette so that Loaded cassettes with it is easily directly over the screens to be tested film strip inside Densitometer if available Set a 100cm FFD (SID) and – Method collimate to cover the step Cut a sheet of film into strips wedge large enough to easily cover the step wedge Cassette and Intensifying Screens Intensifying screens Label the film strips with date and cassette number consistency test For accuracy of this test, the – Method X-ray output and processing Set an exposure that wll give must be consistent a full range of densities on throughout the step wedge image – Evaluation Expose Place the test strips side by Process the film side on the same viewing box Repeat the procedure for all Compare the densities the other cassettes being Assess the density tested, using exactly the differences between the strips same conditions Cassette and Intensifying Screens Intensifying screens – Method 2 consistency test – Equipment required – Evaluation Phantom (water filled flagon, or other suitable, even If the film strip images, using density material of at least screens of similar types, are 30x30cm area) seen to vary noticeably, this is unacceptable (densitometer Loaded cassettes with readings of similar steps screens to be tested should be within 10% of each Densitometer, if available other Assess the density difference betweent the strips Cassette and Intensifying Screens Intensifying screens Collimate to within the phantom so that a portion of consistency test each cassette will be – Method irradiated Place four of the cassettes Set an exposure that will togther, face up on the produce measurable density tabletop, so that one corner of on the film and expose each cassette meets the All screens to be assessed others and the appropriate should be tested in this way, edges are in contact keeping one of the cassettes Set FFD (SID) to 100cm unchanged throughout. Center to the touching Remember to reload the corners of the cassettes control cassette each time. Place the phantom to partially Identify all films using the cover all four cassettes cassette numbers Cassette and Intensifying Screens Intensifying screens – Action consistency test If significant differences are seen you may wish to re – Method screen all cassettes tested. Process the films as soon as If this is impractical, work out possible using the same the exposure differences to processor achieve similar results and – Evaluation label each cassette Compare the densities accordingly. produced on each radiograph – Note Densitometer readings should When equipping a be within 10% of each other department with all new screens it is advisable to carry out this test as a basis for future comparison Grid Grid If the grid is used wrongly, abnormal densities (grid cut – The purpose of the grid is to off) will be produced. e.g. a reducec the amount of focussed grid used upside scatter radiaton reaching down will create a reduction the film. This greatly in density the further the area improves the quality of the is from the center line. image. Although the quality of the image is improved, it does mean a significant increase in exposure, and therefore dose to the patient Grid Care of the Grid – Stationary grids should have an added, rigid, PVC protective cover – When a protective cover is added the grid specifications must be recorded on the new cover for future reference – Do not bend, drop or dent the grid – Clean regularly – Store in a safe place Grid Grid line damage test – Method – Frequency test Visual inspection – Dents, bends, creases, every 6 months damaged corners as necessary – Specifications – Equipment required – Cleanliness Grid to be tested X-ray – Place cassette on tabletop, face One loaded cassette, same up size as grid – Place grid to cover cassette, One lead marker tube side up – Set a FFID (SID) in the middle of the known focal range of the test grid or 100cm Grid Grid line damage test – Evaluation X-ray Is grid line pattern regular? – Center to the middle of grid Is overall density even? – Central ray at 90 degrees to cassette/grid – Action – Collimate to cover cassette/grid If the grid line pattern or – Set an exposure of 50kV density is unacceptable 10mAs (you may need to repeat the test using FFDs expirement prior to the test) (SIDs) of 10cm either side of – Exposre that used un the first test – Process film If the images are still unacceptable, replace the grid File a report Lead rubber aprons and gloves Lead rubber aprons and – Other lead rubber items gloves Gonad shields Thyroid shields – Lead readily absorbs Small sheets are differing radiation radiation and is sizes used in many forms and Shielding on screening units thicknesses in the field of radiation protection – Lead rubber has the advantage of being fleible and can therefore be made into items which can be worn. Lead rubber aprons and gloves Lead rubber aprons and Do not store near a heat source. gloves – Note – Care The lead equivalence of all Weekly cleaning or as forms of lead rubber should necessary. Clean with soap be known. Aprons for and water instance are designed only to Never fold any item of lead protect against scatter. They rubber have a lead equivalent of Aprons should be hung up between 0.25mm and 0.5mm. using strong, specially Lead sheet may have a lead designed hangers equivalent of 2.0mm or Store gloves flat or upright on 3.0mm a custom made holder Lead rubber aprons and gloves Lead rubber aprons and Inspect surface ceovering for tears or sign of deterioration gloves Inspect all seams where – Visual Inspection appropriate – Frequency of test Check flexibility, feeling for every 6 months cracks not seen on the surface as necessary Inspect for cleanliness – Equipment required Check apron hanger devices Items to be tested Assess storage location – Method Check effectiveness and condition of fastenings on aprons Lead rubber aprons and gloves Lead rubber aprons and Carry out X-ray check gloves Relocate storage location if unsuitable – Evaluation Re-design hangers if General condition and unsuitable cleanliness Re-educate staff if they are Possibility of cracks not hanging/storing items Storage location and hanging correctly devices Replace if necessary Are staff using the apron File a report hangers? – Action Initiate any repairs or cleaning required Lead rubber aprons and gloves Test to detect cracking of Use different kVs aprons or gloves If a general purpose X-ray unit is to be used, place – Frequency of test cassettes under test article Yearly and make separate as necessary exposures. Ensure that the whole article is examined. – Equipment required – Evaluation Screening X-ray unit Look for cracks or other Items to be tested abnormal variations of density – Method in the image Spread article to be tested on the tabletop Use screening system to examine whole article Lead rubber aprons and gloves Test to detect cracking of aprons or gloves – Action Items found to be defective should be replaced Items being withdrawn can be cut up into smaller pieces, avoiding the cracked sections. These can be used for gonad shielding or shielding parts of film File a report Viewing Box Viewing Box – Viewing a radiograph under – A viewing box, or light box, good viewing condition is is a simple but important aid important in order to to viewing radiographs and visualize the maximum is commonly used amount of information. throughout X-ray – Regular maintenance and departments. cleaning should be carried – It consists of an even light out. source of sufficient light intensity to allow optimum viewing. Viewing Box Viewing Box – Design – All viewing box should: Two parrallel fluorescent tubes of equal light output, Be conveniently placed with starters Be safely fixed to a wall or A built-in or attached, stable mobile structure spotlight is an advantage Be in good working order The film anchor should hold Be of satisfactory design the film firmly Have an all over even light A good quality switch Be clean inside and out Safe electrical wiring Be electrically safe Have an adequate light output Viewing Box Viewing Box – Method – Cleaning Remove plug from power socket Dust on the window or tube will reduce the light output. Remove the front window Marks on the window can be Clean window on both sides misleading. Clean the back plate and – Frequency of cleaning fluorescent tubes Outside daily Inspect window for damage Inside every 6 months Make sure tubes and starters are firmly in place – Equipment required Replace window viewing box to be cleaned Test clean cloth Screw driver Viewing Box Viewing Box – Evaluation Any dust on inside or outside? Any marks on viewing window? – Action Wipe over with a cloth Use spirit to clean window of hard-to-remove marks Viewing Box Viewing Box – Equipment required – Electrical check Viewing box to be checked This check should be carried Screw driver out by or under the – Method supervision of an electrician. Remove plug from socket Switches , fluorescent tubes, Remove front window starters and electrical Check condition of wirings connections should be checked Check electrical connections Check stability of switch – Frequency of check Check installation of every 6 months fluorescent tubes and starters Replace front window Replace plug in and test Viewing Box Viewing Box – Equipment required – Electrical check Viewing box to be checked This check should be carried Screw driver out by or under the – Method supervision of an electrician. Remove plug from socket Switches , fluorescent tubes, Remove front window starters and electrical Check condition of wirings connections should be checked Check electrical connections Check stability of switch – Frequency of check Check installation of every 6 months fluorescent tubes and starters Replace front window Replace plug in and test Viewing Box Viewing Box in light intensity from one side of the screen to the other or – Evaluation one viewing box to another Electrical connections firm? – Action Electrical wiring in good Tighten electrical connections condition? Refit flourescent tubes for Tubes and started located starters properly and working? Replace tubes or starters if Light source even and necessary comparable to other viewing boxes If, after replacing onl one tube, it is found to be brighter than Replacing fluorescent tubes the remaining one, replace at different time intervals, or both. The working tube that with a different type of tube, has been removed can be may produce a difference matched with another one Viewing Box Viewing Box Light source should be even and the same as other boxes. – Action Replace any faulty parts File a report – Viewing conditions Room light levels in the film viewing area should not be too high A bright spot light should be available for viewing dark areas of the film The viewing box should be mounted at the correct height for easy viewing Patient Positioning Pads Positioning Pads – Routine care – A useful aid to maintaining Care of positining pads should be ongoing the position of the patient. – Try to minimize the risk of – A range of pad sizes and contamination by: shapes should be available » Contrast media » Plaster of Paris in each X-ray room. They » Blood must be radiolucent. » Urine – Pads may be improvised – Inspect and wash regularly using other materials but – Do not use for any other purpose they must be checked for – It may be preferable to cover radiolucency. with waterproof radiolucent material, or removable cotton covers or both. Patient Positioning Pads Positioning Pads – Inspect for – Positioning pad tests Likelihood of contamination Visual General cleanliness X-ray Shape Smell – Visual Test Particles breaking off – Frequency of test Firmness Weekly – Evaluation as necessary Unhygienic? – Equipment required Likelihood of contamination Pads to be inspected by radio opaque substances? Shape, firmness, general deterioration? Patient Positioning Pads Positioning Pads – X-ray test – Action – Frequency of test Wash and re-test if necessary every 6 months If there is a likelihood of as necessary contamination with a – Equipment required radiopaque substance then X-ray unit carry out the X-ray test Pads to be tested If the pad has deteriorated to the extent that it no longer Loaded cassettes as fulfils its function effectively necessary then replace it. Lead marker File a report Patient Positioning Pads Positioning Pads – Evaluation – Method Look for radio opaque shadows within the pad Place a loaded cassette on the tabletop face up – Action Place the pad on the cassette If radiopaque shadows are Set FFD (SID) 100cm detected, wash and dry the pad Collimate to cover the pad Re-test Place the marker in one corner of the X-ray field If opacities are still seen, replace the pad Set an exposure of 50kV and 6mAs Continued use of the pad may be considered, provided Expose it is identified as containing Process the film radiopaque material Patient Positioning Pads Positioning Pads and not used where it might show on the films File a reprot Patient Positioning Pads Other positioning pads – Sandbags – A range of materials can be These are radiopaque. They should have waterproof or used to assist in positioning removable cotton or linen the patient in specific covers that must be washed positions, some radiolucent regularly and some not – Flour bags – Care should always be similar to sandbags but are taken to ensure that radiolucent. radiopaque positioning aids They mould to different do not obscure the image shapes more readily, but are not so heavy as sandbags Patient Positioning Pads Other positioning pads – Water Bottle – Compression band Empty fixer or developer bottles full of water are useful if the band is linen, detach as cassette supports, or in from the end fixing weight bearing views of a/c mechanisms and wash as joints. necessary. Water is relatively radio- if the band is plastic, simply opaque. wipe over with a damp cloth. The ratchet and fixing Little care is required, simply mechanisms should be wipe over the otside of the inspected and tested every bottle with a damp cloth as six months or as necessary necessary. Ensure that the lid is on tightly and that the bottle does not leak. Patient Positioning Pads Other positioning pads – Wooden blocks can be cut – Polystyrene blocks used to to shape pack equipment can be cut – Folded blankets can also be to required shapes useful – Polystyrene chips used in – Note packing can be sealed into It should be remembered that suitable sized cotton or any improvised positioning aid must be checked as to its linen bags radiolucency before use. – Cardboard boxes can be cut down to suitable sizes and shapes and re-stuck Patient Measuring Calipers Measuring Calipers Any distortion may mean that they are no longer accurate – are simple device that allow Store in a safe convenient easy and accurate plave measurement of a body part Clean regularly – Calculating radiographoc exposure factors can be made more accurate by relating them to the thickness of the body part. – Care Handle with care as they are easily bent or broken Patient Measuring Calipers Measuring Calipers Measure the distance between the outer eds of the – Caliper accuracy test two arms at minimal, mid and – Frequency of test maximum distance Monthly Repeat these measurements As necessary at the base of the arms Check against scale – Equipment required Callipers to be tested – Evaluation Measuring device The measurements should be accurate to within + or -2mm – Method Check that the moveable arm is not loose Patient Measuring Calipers Measuring Calipers – Action If the measurements are not accurate, carefully bend the arm If the arm is loose, attempt to tighten it. If unable to correct faults, arrange to have it repaired or replaced File a report