CT
What is CT?
CT (Computed Tomography) is a scanning technique used to view the soft tissue and bone in the body. CT is carried out by using a special machine which produces an image of a cross-section, or slice of the body. The scanner consists of a 'doughnut'-shaped structure, or gantry, through which you pass on a couch.
A narrow fan-shaped beam of X-Rays is produced from inside the gantry, and rotates in a complete circle around you. The X-Rays pass through your body and are detected by electronic sensors on the other side of the gantry, the information passes to a computer which then produces a picture of the internal structure of the body. The pictures are displayed on a monitor and can be printed or downloaded onto CD.
It takes about a second to produce each slice, which can vary in thickness from one millimetre to one centimetre, depending on how much of the body is being scanned. With the new equipment you can take many scans within one breath hold, so it is easy and quick for patients.Because the CT scanner can be used to image the whole body, there are a vast range of potential uses. Some of the more common ones include:
- Diagnosis and staging of a wide range of cancers
- Assessing organ and bone damage to trauma (accident) victims
- Planning radiotherapy treatment regimes
- Assessment of vascular (blood flow) diseases
- Screening for and assessing cardiac (heart) disease
- Assessment of injury and disease to bones, particularly in the spine
- Bone mineral densitometry for the assessment of osteoporosis
- Guiding biopsy procedures for taking tissue samples
The advent of Spiral CT technology enabled the table to advance continually as the tube and detectors revolved, thus producing a continuous spiral (or volume) of data which the computer could then process into sectional images. This has greatly improved the speed at which CT data can be acquired so that the entire chest, for example, can be examined in a single breath hold.
About your CT appointment
If you have any queries, before you come for your appointment, please call us on 020 7467 8800, our reception staff will be pleased to help. On the day of your scan, you will meet the radiographers who will look after you during the examination. When completed the results will be interpreted by a consultant radiologist and forwarded to your referring doctor. Please note that all underwear containing metal needs to be removed. It may also be advisable to wear loose baggy clothing with no metal e.g. tracksuit bottoms, t-shirt, sweatshirt etc and it would be helpful to remove metallic objects before scan appointment, which includes keys. It can sometimes become cold in the scanner, so it may be advisable to wear socks.
Before your appointment
It is very important to follow all the instructions given to you regarding eating, drinking and taking medication before your appointment. If you have any queries or need advice please contact us on 020 7467 8800. You may be required to arrive an hour before your scan time in order to drink some contrast agent (which is explained further below). You will be advised of this when making your appointment.
Ladies: if you could be pregnant or are in the first six months of pregnancy, please let us know.
If you need help because you speak a different language, please let us know when you book your appointment.
On Arrival
On arrival one of our staff will explain the procedure to you, run through a simple safety questionnaire to make sure you can be scanned and answer any further questions you may have. Some CT scans require the use of a "contrast" which can be a drink or injection, this is used to enhance the image and give a clear view of your condition.
The Examination
The radiographer will take you into the scanner room and position you on the scanner. During scanning we may ask you to keep still or hold your breath at certain times. The scan is completely painless; all you will hear some mechanical sounds from the scanner.
During the entire examination, the radiographer can see you clearly and speak to you via a two-way intercom - so if you have any problems, you only have to speak.
Examination times depend on the area to be scanned. We advise you to allow up to an hour for the scan. For certain conditions an injection may be required to help the radiologist to see the problem more clearly. This injection is safe and will cause no after-effects.
CT Dental Scanning
The London Imaging Centre works in conjunction with IDT to provide specialized CT dental scans for patients requiring dental implants. We scan the patients upper or lower jaw (sometimes both depending on what is needed) and electronically send the digital images and information to IDT for reformatting. IDT then provides specialized implant mapping information back to the referring dental implant surgeon, so that they are able to efficiently plan the dental implant surgery according to bone depth, density and alignment.
