In patients with either chronic or slow gastrointestinal bleeding it can be difficult to identify the source of the bleeding. Usually endoscopy is performed, but if the source is not readily apparent, further imaging may be required. A CT scan of the mesenteric vessels can sometimes be useful, but relies on the presence of active bleeding at the time of the scan to be diagnostic.
Using radioactively labelled red cells, we can often accurately identify the source of bleeding, anywhere along the gastrointestinal tract. The advantage of this nuclear medicine technique is that it is more sensitive for slow bleeds which may not be visualised on CT scans. By combining the nuclear medicine scan with a SPECT-CT, we can produce three-dimensional images which can localise the bleeding source to a specific loop of bowel. This is a useful, non-invasive test, which only relies on a simple injection and a scan in order to produce a result in a matter of hours.
GI bleeding study preparation
What is a nuclear medicine GI bleed scan?
Your doctor may recommend a GI Bleeding Scan to help locate the sites of either a gastrointestinal or non-gastrointestinal bleeds, which include the stomach and small and large intestines.
In a Gastrointestinal (GI) Bleeding Scan a small amount of a radiopharmaceutical will be injected into a vein. Pictures of your abdomen will start immediately, lasting for approximately one hour or longer, looking for an area of bleeding in the intestinal tract.
Are there are any risks?
As the gamma rays are like X-rays, there are small risks associated with being exposed to radiation. However, the radiation decays away over a few hours and the amount of radiation used in medical imaging is very low. This is comparable to the natural radiation we all receive from the environment over about one year. In fact, the risks from missing a disorder by not having the study may be greater than the risks of the radiation. If you are concerned about the risks of the radiation, please speak to a member of our team.
Is there any special preparation for the scan?
You will need to fast for 6 hours before the scan.
When you make your appointment, you will be asked what medication you are currently taking, and we may ask you to stop certain medicines before the scan.
If you are pregnant or breastfeeding
If you are pregnant, or think you may be pregnant, you mustinform the department before attending, and certainly before the radiopharmaceutical is administered.
If you are breastfeeding, please inform the department before attending and you will be advised as to whether you will need to take any precautions. You may be advised to avoid breastfeeding for a few hours afterwards and you may need to express milk before your scan.
Can you bring a relative/friend?
Yes you can, but for reasons of safety, they may not be able to accompany you into the examination room, except in very special circumstances. Please do not bring children with you as they will potentially be exposed to radiation from other patients.
Arriving for your appointment
When you arrive for your appointment, please go to the reception desk, after which you will be shown where to wait until collected by a technologist.
The technologist will explain the procedure, and you can ask any questions. You may be asked some questions about your health, or whether you have had this examination before. You do not need to undress but you should remove any jewellery and metallic objects such as keys, coins or buckles.
What happens during the scan?
You will be taken to the examination room and made comfortable lying down on the examination couch. The technologist will give you an injection of a pre-treatment medicine and the radiopharmaceutical into a vein in the arm.
The technologist will position the gamma camera over your abdomen, and it will remain still, continuously taking pictures of your intestines. The scan typically lasts one hour, and it is important that you lie still during this scan.
Sometimes, your technologist may need to perform another view where the camera moves around you in a circular motion. This is called a SPECT scan. This can be combined with a CT or CAT scan and is then called a SPECT-CT scan. Your technologist will tell you if this is going to happen.
Will it be uncomfortable?
No. Apart from the injection, you will not feel anything.
How long will it take?
The scan lasts up to one hour, but occasionally your technologist may need to take further delayed pictures.
Can I listen to music or watch a movie while I have my scan?
Your technologist will ask you whether you would like to listen to music or watch a movie during your scan. You may bring in a CD or DVD, or select music from our selection.
Are there any after-effects?
The radiopharmaceutical causes no side-effects, nor will you feel drowsy. You can drive home afterwards and go about your normal activities.
In addition to mothers who are breastfeeding, parents with young children should notify the technologist, who will explain that it is advisable not to have prolonged close contact with them for the rest of the day. This is to avoid them being exposed to unnecessary radiation.
When will you get the results?
The scan will be examined after your visit and a written report on the findings will be sent to your referring doctor within 48 hours.
The radiopharmaceutical required for this examination is ordered especially for you. If you cannot attend your appointment, please let the department know as soon as possible, so that we can use it for someone else.
We hope that this leaflet has answered your questions, but remember that this is only a starting point for discussion about your treatment with the doctors looking after you. Make sure you are satisfied that you have received enough information about the procedure.