DMSA, or dimercaptosuccinic acid, is a radioactive substance (called a radiopharmaceutical) that is injected into a vein and enters the kidneys. The gamma rays that are emitted from the radiopharmaceutical are detected by gamma cameras and enables a picture to be taken of the inside of the kidneys.
The scan shows which areas of the kidneys are working normally and which areas have been damaged (usually following kidney infections).
Typically your doctor will request a DMSA scan when they want to know if there is any evidence of scarring in the kidney, and whether there is any difference in function between the two kidneys. DMSA scans are often performed in children who have had urinary infections, but can also be performed in adults. They are also performed in patients who are being considered for surgery to their kidney to remove part of it (a partial or total nephrectomy).
The DMSA scan can be combined with a single-photon computed tomography (SPECT) scan to given a three-dimensional image of the kidney.
At Trinity Medical Imaging we are pioneers in the development of hybrid imaging techniques. As a result, we are the first centre to offer combined DMSA scans with contrast-enhanced SPECT-CT. This allows us to simultaneously assess the kidney function and delineate the anatomy of the urinary system. This is particularly useful in patients with stone disease being considered for pyeloplasty or surgical planning in patients with renal tumours.
DMSA scan preparation
What is an isotope kidney (renal) scan?
The isotope kidney (renal) scan involves an injection into a vein in the arm of a small quantity of radiopharmaceutical. This goes around in the bloodstream, and is taken to the kidneys. The gamma camera detects the radiation coming from the kidneys. A picture is produced of the kidneys showing what they look like.
What does DMSA actually stand for?
It is dimercaptosuccinicacid. This is the substance that the tracer, technetium 99m, is attached to, and which is taken up in the kidneys.
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 6 months. In fact, the risks from missing a disorder by not having a scan may be considerably 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.
Are you required to make any special preparations?
No, you may eat and drink normally and you should take any medicines you need as usual. If you leave the department, you do not need to take any special precautions, but if you stay in the department then you should use the special toilet for nuclear medicine patients.Your technologist will show you where the toilet in the department is.
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 have the opportunity to ask any questions. You may be asked some questions about your health, or whether you have had this examination before.
The technologist will then give you the injection of radiopharmaceutical preparation into a vein, generally the one near your elbow. This is just like having blood taken.
There is then a two- to three-hour wait to allow the tracer to be absorbed by the kidneys, during which time you may leave the department.
What happens during the scan?
You do not need to undress but you should remove any jewellery and metallic objects such as keys, coins or buckles. You will be taken to the examination room and made comfortable lying on the special couch. The technologist will position the gamma camera over your abdomen and ask you to lie still. The technologist will remain in the control room and watch you through the glass screen in the examination room. It will be necessary to take up to six different views or one continuous rotation of the camera (called a SPECT scan).
Will it be uncomfortable?
No. Apart from the injection, you will not feel anything.
How long will it take?
It takes 2–3 hours while the isotope is absorbed into the kidney. The scanning process usually takes 30 minutes, and your time in the department will be less than one hour in total.
Can I listen to music while I have my scan?
Your technologist will ask you whether you would like to listen to music during your scan. You may bring in a CD or select music from our selection.
Are there any after-effects?
No, the injection causes no side-effects, nor will you feel sleepy. 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 radiographer, 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 7 days.
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.