CT scans (Computed Tomography) Informaton for patents Radology
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What s a CT scan? CT s a short way of sayng Computed Tomography. Computer Tomography scannng s used commonly n the dagnoss of llnesses today. It s smlar to conventonal radology as t uses x-rays. However, a CT scan uses a specalsed computer to produce detaled mages n 'slces' through the body. These mages can then be put together to create a 3D pcture of your body. What s a CT scan used for? CT scanners can be used to mage dfferent parts of the body such as: Internal organs wthn the chest and abdomen such as the lungs, lver and bowel Bone magng such as the ankle/foot Head and bran magng Vascular magng to examne the blood flow. Why do I need a CT scan rather than a normal x-ray? A CT scan produces more detaled mages than an x-ray pcture. CT mages are good n dstngushng between dfferent types of soft tssue. These can be put together to produce 3D mages whch may help provde extra nformaton about your condton. You wll have recently seen your doctor about a medcal problem. Your doctor should have dscussed the reason for wantng a CT scan. If you are unsure as to why the scan s necessary, t s best to talk to your doctor as they wll have all your detals. page 3 of 16
What does a CT scanner look lke? A CT scanner looks lke a gant polo mnt. It s crcular wth a large hole n the mddle and s open at both ends. Durng the scan you wll be asked to le on the scan table. The table wll move n and out of the scanner as t takes the mages. What wll happen when I arrve? On arrval n the x-ray department please tell the receptonst that you are here. You wll be asked to take a seat n the watng area. You wll then be collected by a clncal assstant or radographer who wll take you to prepare for your scan. Consent We must obtan your consent for any procedure or treatment beforehand. Staff wll explan all the rsks, benefts and alternatves before they ask for your consent. If you are unsure about any aspect of the procedure or treatment proposed, please do not hestate to ask for more nformaton. page 4 of 16
Wll I need any specal preparaton for the scan? You may need specal preparaton dependng on the type of scan you are havng. Your appontment letter wll ndcate whether you need preparaton for the scan and you wll be asked to come to the CT department up to one hour before your appontment tme. Ths s so you can drnk some flud that helps to show up the stomach and bowel areas better and provdes more nformaton on the scan. You wll be asked to drnk 1 ltre of flud before the scan. Your co-operaton s mportant and drnkng the full amount of the preparaton drnk helps the Radologst nterpret the scan and wll help gve more accurate results. For some scans no preparaton drnk s requred. Wll I need an njecton? For the majorty of CT scans you wll requre an njecton of x-ray contrast (dye). Ths s not a radoactve substance. Ths lqud hghlghts your blood vessels and organs on the scan pctures and helps gve more detaled nformaton. Scans requrng preparaton and njecton Head scans: No oral preparaton s requred. Most head scans are performed wthout the njecton of x-ray dye, however, an njecton of dye s occasonally gven to provde more nformaton. Chest scans: No oral preparaton s requred. Most chest scans are performed usng an njecton of x-ray dye. Abdomnal and pelvc scans: Both oral preparaton and njecton of x-ray dye are usually requred for abdomnal and pelvc scans. Further preparaton before and durng abdomnal and pelvc scans may be requred. You wll be gven further nformaton f any extra preparaton s necessary for your scan. page 5 of 16
Orthopaedc (bone) scans: These are scans of your spne, pelvs, upper and lower lmbs to look specfcally at the bones and jonts. No oral preparaton or njectons of x-ray dye are usually requred for these scans. Vascular scans: These are scans to look specfcally at the blood vessels n your body. No oral preparaton s requred. An njecton of x-ray dye s requred to hghlght the blood vessels. A combnaton of these scans can often be performed together, therefore the oral preparaton and njecton requred may alter from the nformaton gven above. Who performs my scan? The person who carres out the scan s called a radographer who wll explan your procedure thoroughly when you come for your appontment. A radologst (a doctor specally traned n lookng at x-rays) wll nterpret the scan and send the results to your doctor. What wll happen durng the scan? When t s tme for your scan you may be asked to change nto a hosptal gown, you wll then be asked to le on the scanner table. If you requre an njecton of x-ray dye the radographer wll go through the questonnare you have been asked to complete, to ensure that t s safe to gve you the njecton. A small needle (cannula) wll be placed nto your arm to allow the x-ray dye to be admnstered durng the scan. The x-ray dye wll not be njected straght away, the radographer wll need to do some plannng scans frst but wll warn you when the dye s beng njected. You wll be scanned several tmes, durng whch you wll move n and out of the scanner. For the majorty of scans you wll be asked to hold page 6 of 16
your breath for up to 15 seconds. It s mportant that you hold your breath and keep stll as breathng and movng causes blurrng and can run the scan pctures. The CT scanners at the Sheffeld Teachng Hosptals are very fast modern scanners. What happens after the scan? Once the scan s complete you wll be asked to return to the cubcle to change. In some cases you wll be able to leave the department mmedately. If you have been gven the njecton of x-ray dye durng the scan you wll be asked to wat n the department for an extra 15 mnutes, the cannula wll be left n your arm. Ths s because we need to montor you to make sure the effects of the x-ray dye have worn off and that you feel alrght before you leave. Once your cannula has been removed by a member of the CT staff, pressure wll need to be appled to the ste to prevent brusng, you wll then be able to leave the department. Be careful not to knock the njecton area once you have left the department, partcularly f you take asprn or warfarn as ths can cause the area to bleed agan. If bleedng does occur, apply pressure to the area usng a clean cloth or gauze to stop the bleedng and reduce any brusng. The njecton of x-ray dye causes no known effects on the ablty to drve or operate machnery. However, due to the rsk of reacton (see rsk secton, page 8), patents are advsed not to drve or operate machnery for one hour after the njecton. How long does t take? A scan can take anythng from 5 to 20 mnutes dependng on the type of scan you are havng. Please be aware that you may be asked to arrve up to an hour earler f you need to have a drnk before the scan. If you have been gven the njecton of x-ray dye durng the scan you wll be page 7 of 16
asked to wat n the department for an extra 15 mnutes. You should antcpate beng n the department for up to two hours. Due to the nature of our workload we often have to perform emergency scans whch must be prortsed. Whlst we try to keep to appontment tmes ths may occasonally cause slght delays wth routne appontments. We thank you for your patence. Are there any rsks? There are a few rsks nvolved wth a CT scan. They nclude: Radaton - A CT scan uses radaton n the form of x-rays to form the mages. The amount of radaton used s more than for an ordnary x-ray of the same area but s equal to the amount of natural radaton from the atmosphere we all receve over a few years. Ths adds very slghtly to the rsk, for example, of developng a cancer. However, ths rsk s very small. The amount of radaton s kept to a mnmum to reduce ths rsk and a CT scan s consdered a safe procedure. Your doctor has chosen ths test for a good reason and the rsk of mssng a problem by not havng the scan may be consdered a greater rsk. The effectve radaton dose for a: CT head scan s 2 msv whch s equvalent to 1 year of background radaton receved for an adult. CT chest scan s 8 msv whch s equvalent to 3.6 years of background radaton receved for an adult. CT abdomen scan s 10 msv whch s equvalent to 4.5 years of background radaton receved for an adult. For more nformaton regardng the rsks of radaton vst the Health Protecton Agency at www.hpa.org.uk page 8 of 16
Radaton, pregnancy and women of chldbearng age - If you are of chld bearng age and are stll havng regular perods we may need to know the dates of your last menstrual perod. For the majorty of scans we wll only need to know that you have had a perod wthn the last month and are not overdue. If you are havng a CT scan of your lower back, abdomen or pelvc area we need to ensure that the frst day of your last perod s wthn 10 days of the scan. Ths s to ensure that we do not mstakenly rradate a foetus/unborn baby. You may be asked to book the CT appontment to concde wth these dates. However, f you attend for your scan and are outsde of these dates you wll be asked to take a pregnancy test to ensure you are not pregnant. Ths s precautonary, but for safety and legal reasons must be done. X-rays can be harmful to your unborn baby, t s mportant to tell the CT staff f you are or thnk you may be pregnant. page 9 of 16
Reacton to the njectons - The x-ray dye used for ths test contans odne and t does have some natural sde effects, whch are: Hot flush Metallc taste n the mouth Sensaton of passng water These usually pass wthn a few mnutes. We take every precauton to ensure that you wll have no adverse effect from the njecton, however very occasonally (n less than 0.03% of cases) patents can have an allergc reacton to the dye. Ths can manfest tself as an tchy rash, shortness of breath and, n extremely rare occasons, swellng of the throat and other body parts. A reacton to the x-ray dye usually occurs wthn mnutes of the njecton, however on rare occasons a reacton may not occur untl you have left the scannng department. If you experence a reacton after you have left the department do not hestate to contact your GP or the local A&E department. Please nform staff of any allerges you may have to prevent the occurrence of an allergc reacton. Asthma - On rare occasons the x-ray dye can brng on an asthma attack, f you are asthmatc please remember to brng your nhalers wth you. Kdney Functon - The x-ray dye njecton can cause your kdneys to work more slowly. Ths s only a problem f you already suffer wth kdney problems. If you have not had a recent blood test you may need to have one before the scan to check your kdneys are workng properly. You should only requre a blood test f you are a dabetc takng Metformn (Glucophage), have exstng kdneys problems or are aged 65 or over. Your doctor wll organse ths for you. page 10 of 16
Dependng on these blood results you may need to be hydrated before and after the scan, ths can nvolve drnkng 1 ltre of water before and after the scan or you may need to come nto hosptal and be put on a drp for a few hours before and after the scan. Once we receve your blood test results you wll be nformed f ths s necessary for you. The short questonnare you have been asked to complete provdes nformaton to help reduce the rsk of an allergc reacton and medcal problems. Please remember to complete ths and hand t n when you attend for your scan. Shall I contnue takng my medcaton? Yes, contnue takng any medcaton unless you are advsed otherwse. If you are dabetc and takng Metformn you may need to stop takng ths. If you are dabetc and takng Metformn please contact the CT scannng department as soon as possble. Our telephone number s provded on your appontment letter. When wll I get my results? We cannot gve you your results straght away because the radologst wll need tme to revew the scan n detal. Your results wll be sent to the doctor who referred you for the scan. You may have an outpatent appontment booked wth your doctor at whch you can dscuss the results of the scan. If you have not arranged to see your doctor already you wll be sent an appontment once your doctor has receved the results. page 11 of 16
Are there any alternatve tests? Your doctor has referred you for a CT scan because they feel that ths s the best test for you. However, f you feel unhappy about havng a CT scan there may be alternatve tests that you can have. You wll need to dscuss these wth the doctor who has asked for you to have the scan. What f I stll have some questons? After readng ths leaflet, f you want to know more, or have any concerns, you can contact the doctor who referred you for the scan, the CT scannng department or you can ask the radographer when you arrve for the scan. If you cannot make your appontment or have any queres please contact the CT scannng department. Our telephone number s provded on your appontment letter. Alternatvely you can emal: Jenny.Brathwate@sth.nhs.uk CT & MRI Manager Sheffeld Teachng Hosptals page 12 of 16
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SERVICE ROAD C MEDICAL SCHOOL DAY CASE CENTRE ROYAL HALLAMSHIRE HOSPITAL B ROAD THEATRE ADMISSIONS DIABETES CENTRE OUTPATIENTS DEPARTMENT Royal Hallamshre Hosptal CRESCENT CLAREMONT PALMERSTON ROAD NORTHUMBERLAND ROAD SHEARWOOD ROAD CLAREMONT PLACE TREE ROOT WALK WALK-IN CENTRE UNIT GUM CLINIC MULTI STOREY CAR PARK GLOSSOP ROAD A ROAD 1 2 3 Medcal Imagng (C Floor) BEECH HILL ROAD page 15 of 16
Northern General Hosptal P Car Park P North Lane SouthLane Central Way Medcal Imagng (Vckers Corrdor) Central Lane Clock Tower Chesterman Wng Sheffeld Kdney Inst. Frth Wng Herres Road Entrance Parkng P P Car Park 15 P Publc Car parks (Pay & Dsplay) Out Patents 2 Herres Road Drve Herres Sorby Wng Road Vckers Corrdor Huntsman Buldng P Day Surgery Unt Car Park D P Car Park E Brearley Wng Brearley Drve Hadfeld Wng P Huntsman Drve Barnsley Road Drve Car Park A Frvale Way 15 Barnsley Road Barnsley Road Entrance Dsabled Parkng Spaces (Free Parkng) Frvale Pedestran Entrance Produced wth support from Sheffeld Hosptals Charty Workng together we can help local patents feel even better To donate vst www.sheffeldhosptalscharty.org.uk Regstered Charty No 1169762 Alternatve formats can be avalable on request. Please emal: alternatveformats@sth.nhs.uk Sheffeld Teachng Hosptals NHS Foundaton Trust 2017 Re-use of all or any part of ths document s governed by copyrght and the Re-use of Publc Sector Informaton Regulatons 2005 SI 2005 No.1515. Informaton on re-use can be obtaned from the Informaton Governance Department, Sheffeld Teachng Hosptals. Emal nfogov@sth.nhs.uk PD6116-PIL682 v4 Issue Date: October 2017. Revew Date: October 2019