COMMONLY PERFORMED INVESTIGATIONS

Commonly performed investigations

LUNG

Ventilation/perfusion (V/Q) scan:

The V/Q study is performed to detect pulmonary emboli within your lung blood vessels, these are small clots that block the blood flow to your lungs.

It is performed in 2 stages:

Stage 1: You will be asked to inhale a radioactive gas before you are placed on our specialised camera for imaging of your lungs.  This will allow us to evaluate the airflow in your lungs. Please note that this gas will not cause drowsiness or any other symptoms.

Stage 2: An initial baseline scan is performed, thereafter you will be injected, you will be injected intravenously with a small amount of a radioactive substance, followed by a second scan. These images are used to assess the blood flow within your lungs. 

A nuclear physician will evaluate and compare the two sets of images to determine if you have a pulmonary embolism.

No preparation is needed for this study. You can eat and drink normally before and after the study.

These scans are also safe to perform in pregnant patients and during breastfeeding; however, a specific protocol is then followed – please contact the practice for further instructions prior to your procedure.

Lung quantification:

This study is used to determine what contribution certain parts of your lungs have to the total lung function. It is often used prior to surgical removal of part of a lung, to determine if enough lung tissue will be left post surgery to maintain adequate oxygen saturation. 

A radioactive isotope will be injected and images of your chest will be acquired. The contribution of each part of the lung will be calculated and reported to your referring doctor.

No preparation is needed for this study, you may eat and drink normally before and after the study. 

Referring doctors, please inform us if your patient has pulmonary hypertension as the radiopharmaceutical preparation will need to be adjusted accordingly. 

CARDIAC

“MIBI” (Myocardial perfusion imaging):

This study is used to evaluate the blood flow in the heart muscle and the function of the left ventricle of the heart. There are multiple reasons why your doctor may request this study, but it is often used to determine what therapy would be best in your unique medical situation or to determine if there are any irreversible damage to your heart muscle after a heart attack.

This study is performed in 2 parts/stages: A “resting” study and a “stress” study: these are then compared to answer the question of your referring clinician.

For the “resting” part of the study, you will receive a radioactive injection and imaging will commence 45 minutes later. After this has been completed, the 2nd part of the study will be performed.

During the “stress” part of the study – you will either do physical exercise (on a treadmill) or you will be injected with a medication that causes a similar physiological reaction in the heart as during exercise. Your ECG and other vital signs will be closely monitored during this part of the study. After your heart has reached the desired state – you will again be injected with the radioactivity and images will be done after 15 – 45 minutes (depending on the type of exercise performed).

The choice of exercise method will be determined by your referring doctor and the nuclear medicine specialist in charge of the study.

Correct preparation is of utmost importance for this study. The preparation depends on what type of exercise/stress method will be used. Please contact us if you are not sure about the preparation instructions or if you have any questions. Please also refer to our downloadable brochure about MIBI studies on this website.

 

  • If physical exercise will be used, Beta-blockers (e.g. Atenolol, Propanolol, Carvedilol) MUST be stopped for 3 days. If for medical reasons the medication cannot be stopped please let us know – as a pharmacological stress study will be done
  • If possible Calcium-channel blockers (Amlodipine) should also be stopped for 48 hours prior to the study.

If pharmacological stressor will be used

  • Long-acting nitrates (Elantan or similar )                                        3 days
  • Long-acting nitrates (Elantan or similar )                                        3 days
  • Theophylline (or similar) 5 daysIsordil/Nitrolingual spray :       12 hours 

Please remember if you experience severe chest pain before the study and need to use your medication to relieve this pain (eg isordil/nitrolingual spray), please use the medication as instructed by your treating physician and inform us that you have used it. We will then decide if the study needs to be rebooked or if we can continue.

MUGA

This study is used for the evaluation of your left ventricular ejection fraction (LVEF) – this is the amount that is pumped from your left ventricle (heart chamber) to the body. It also evaluates the strength of the contraction of your heart muscle. Several factors/diseases may cause an impairment in the way the heart contracts, this may include previous heart attacks, viral infections, medications like chemotherapy or chronic diseases (eg diabetes/hypertension). This study can be used to determine what the power of each contraction of the heart is.

There is no preparation needed for this study.

SKELETAL

BONE SCAN:

Bone scans are used in many different settings – It is unique in the fact that it can image bone turnover at a very early stage and changes can be seen long before anatomical abnormalities can be detected. A bone scan can be used in n benign (non-cancerous) diseases – and some of the many uses, includes identification of bony infections, to determine the cause of pain after joint replacements or even in sports injuries (stress fracture and shin splints). One of the commonest indications are however to diagnose metastatic skeletal disease in various types of cancers as a bone scan has a high sensitivity for osteoblastic skeletal metastases.

A radioactive injection will be administered intravenously. You will be asked to come back 2-3 hours later for the imaging part of the study. In certain indications we may do some imaging directly after the injection as well. The study will take about 3-4 hours to be completed (from time to injection to completion of the images). You may eat and drink normally during this time. You do not have to wait at the practice between the injection and the scan.

No preparation is needed for this study. You may eat and drink before and during the study. We encourage you to drink at least 4 glasses of water after the injection to improve our image quality and improve excretion of the radioactivity.

KIDNEYS

RENOGRAM:

This study is done to evaluate your kidney function. There are many different reasons why your referring doctor would ask for this study. Usually, it is to see if both kidneys are functioning similarly or to make sure that there is no obstruction (blockage in the flow of urine).

The study takes about 1 hour to complete. We inject you with a radioactive substance while you are lying under the camera. We will then take pictures for 30 minutes. We will then ask you to empty your bladder and do a few more studies. The doctor will then look at your scan and interpret the findings.

Your report will be sent to your referring doctor.

Make sure you are not dehydrated when you come for the study. Please drink enough water the day before and the morning of the study. No other preparation is needed

Cystogram

A renogram will also be done before the cystogram. The cystogram is used to determine if there is “reflux” into the kidney (any flow from the bladder back to the kidneys, especially during times of increased pressure (eg during voiding of your bladder).

We will ask you to empty your bladder while sitting in front of the camera – patients that are booked for this investigation, must be able to follow instructions and void on command (therefore cannot be done in small children and babies).

DMSA

A DMSA study can be used to determine if there has been any injuries/insults to the kidneys that have caused permanent damage (scarring). It is often requested after infections of the kidneys to determine if there were permanent damage. It is also used to determine what each kidneys contribution to total renal function is (Differential function)

 

BRAIN

BRAIN PERFUSION SCAN:

These scans are usually done to look at the blood flow in your brain. We will ask you a few questions and get a history from you before we start with the examination.

We will put up an IV cannula and let you lie in a fairly dark room to relax before the study. You must please switch off your cell phone during this time. If there is someone accompanying you, they are NOT allowed to talk to you during this time. You must relax and you may close your eyes, but you must please try not to fall asleep. After about 30 minutes the radiographer or doctor will enter the room and inject you with a radioactive substance. You must NOT talk to the radiographer when he/she enters the room. After the injection, we will wait about 10 minutes before we come and fetch you. When this time is over you can continue with normal activities (eg talking, reading) while waiting for us to do the images.

The scan takes about 30 minutes to be completed. When the scan is done you can go home and continue with normal daily activities.

A nuclear physician will interpret the study and the report will be sent to your referring doctor.

You must not take any sedatives the morning before the study. You must also not drink/eat any caffeine-containing drinks or food.

ENDOCRINOLOGY

THYROID UPTAKE SCAN:

This test is usually done when your referring doctor have found that your thyroid gland is overactive.

We will inject you with a radioactive substance that gets taken up by the thyroid gland. 20 minutes after the injection we will put you on the camera and take pictures of your thyroid gland. Occasionally we will ask you to have a drink of water and we will take some more pictures.

After the investigation you can go home and continue with your normal daily activities.

Please inform the staff if you are on any medication (eg Neomercazole, Eltroxin, beta-blockers, Amiodarone) when the booking is made, as this may influence interpretation of your scan.

There is no preparation needed for the study. You may eat and drink normally before and during the study.

 

PARATHYROID SCAN:

 

Your parathyroid glands are small little glands located just behind your thyroid gland. Its main function is to regulate your calcium levels. Your doctor have diagnosed that your glands may be overactive.

A radioactive substance will be administered intravenously, imaging will start 20 minutes after the injection. We will also scan you 2 hours and 3 hours after the injection. You may eat normally before, during and after the study.

Preparation: Please inform us if you are on thyroid replacement therapy (ie Eltroxin or thyroxin) when the booking is made. We might have to stop this before this investigation. Calcimimetics and Vitamin D supplements must also be stopped before the study. In addition it is preferable that you should not have had any diagnostic imaging with intravenous contrast in the 4 weeks prior to the study. Please contact us to discuss your unique case with us before the study.

ONCOLOGY

 

I-123 WHOLE-BODY SCAN:

This study is performed in patients with follicular or papillary thyroid cancer. The first study will be done after your thyroid has been removed – this is to determine if there are any thyroid tissue left and/or if any metastases are present. It is also used for follow-up in patients with (previous) thyroid cancer.

The radioactivity gets administered in a tablet form. A day after administration (24 hours) of the radioactivity you must please come back to our department for the images.

In some instances (when I-123 is not available), I-131 can also be used. Preparation before the study is the same as for I-123

Preparation before the study is important. For accurate results, we require that your TSH level is >30IU before/during the study. To achieve this, it is necessary to either stop your thyroid hormone replacement therapy (eg Eltroxin or thyroxin) for 4-6 weeks before the scan OR 2 weeks if you are taking T3. If you do NOT wish to stop your medication you may take “Thyrogen” before the scan – (You will need to get medical aid authorisation for this). Please see the section on Thyrogen (under preparation before studies).

If you decide to rather stop your hormone replacement your TSH level will have to be done 1 week before the study (before we order your dose.) This is to verify that your TSH level is appropriate before the study. PLEASE DO NO RESTART YOUR ELTROXIN BEFORE THE SCAN, EVEN IF YOUR TSH LEVEL IS AT THE APPROPRIATE LEVEL – this will cause the scan to be unreliable.

 

I-131 POST-ABLATION SCAN:

After you have received your THERAPEUTIC I-131 for the treatment of your thyroid cancer, you will come to our department for a whole-body scan. This is to determine if the I-131 has gone to all the areas that still showed uptake on the I-123 scan. This study is usually done a minimum of 7 days after you have received your therapy but maybe as long as 14 days after therapy. The number of days will depend on various factors, for example, what dose you received etc. The timing of the study also depends on when you are discharged from the hospital after your treatment.

After the therapeutic dose of I-131, your referring doctor will start/restart your I-131. You can take this tablet as before. NO other specific preparation is needed before the study.

I-123/I-131 MIBG:

MIBG is a noradrenalin analogue and can be used to diagnose certain types of cancers/growths of the adrenal glands. These are called pheochromocytomas. Similar tumours can also be found outside of the adrenal glands and are then called paragangliomas. It may also be used in Neuroblastoma

There is a long list of medication that needs to be stopped prior to the investigation. We will contact you when making the booking to get a list of the medication you are taking. If you are booked for the study, please do NOT take any over the counter medication before discussing it with us. Certain “over the counter” cold and sinus medication has to be stopped for a certain amount of time before the study. Please also note that we will order this tracer specifically for you and if you have not followed the correct preparation we will NOT be able to do the study OR we will not be able to get reliable results. Please do NOT omit any medication you are taking as correct preparation is of utmost importance.

The advantage of MIBG is that it can be used for diagnosis and therapy. Therefore if we prove that your tumour does take up this tracer, I-131 MIBG is a therapy option.

SENTINEL LYMPH NODE STUDY:

This study is done the day before or the day of your surgery. It is to detect to which lymph nodes your tumour drain first. This lymph node (s) will then be removed during surgery and evaluated by a pathologist.

The radioactive substance will be injected just underneath your skin in the area of your tumour (or scar). You will be placed under the camera immediately and images will be done for about 30 minutes. Images will also be done 1-2 hours after administration of activity depending on varying factors.

Uptake of activity on the scan is NOT indicative of cancer in the nodes. The absence or presence of cancer in the nodes can only be determined after evaluation by the pathologist. Our images only serve as a “roadmap” to tell the surgeon which nodes to remove for evaluation.

There is no preparation needed for the study. You may eat and drink normally before and during the study.

GASTROINTESTINAL STUDIES

GASTRIC EMPTYING STUDY:

The study is to determine whether your stomach empties at a normal rate or not. We will give you a small meal consisting of egg and bread that has been mixed with some radioactivity.

After eating this radioactive meal we will take images for 30 minutes and then hourly for up to 3 or 4 hours.

We will then calculate your “gastric emptying rate” which will then be reported and sent to your referring clinician.

You may not eat 4 hours before the study.

Certain medications may affect your gastric emptying rate, we request that you do not take these for 12 hours before the study. This includes opioids for pain relief (eg morphine, tramadol), anti-nausea medication (stemitil, maxolon), anti-diarrheal medication and medication for stomach cramps (buscopan, immodium). If you are uncertain if you are allowed to take your medication please contact us for clarification.

GIT Bleed:

This is used to detect small bleeds in your bowel, that cannot be detected by conventional methods.

Blood is taken from you and will be labelled with a radioactive tracer. We will re-inject your OWN blood and then start with the imaging procedure. Initially, a series of images taken shortly after each other will be done up to one hour. Thereafter images will be taken hourly. We may take images up to 24 hours after the injection.

We can then determine if we see blood outside of the normally expected areas and guide your surgeon where the bleed is coming from.

No preparation is need for this study.

Hepatobiliary study:

This study is requested to look at the biliary system. It can be used, amongst other indications, to determine if the gallbladder is not contracting properly. If acute or chronic cholecystitis is suspected or obstruction of the biliary system this study can be very useful.

It may also be used in babies where gallbladder atresia is suspected.

You need to be fasting for 4 hours, but not longer than 24 hours.

Milk scan:

A milk scan is mostly used to assess possible reflux in a child. Other functions can also be evaluated:: The swallow, the refluc and the gastric emptying.

This can be done as early as 4 weeks after birth, but if the swallow needs to be evaluated the child must be able to drink from a bottle.

A small amount of radioactivity is given with the babies milk, he will feed.

INFECTION IMAGING

Different types of infection imaging can be done: Your referring clinician would have most likely discussed it with one of our Nuclear Physicians’ to discuss the most appropriate investigation.

Bone scan:

For suspected infections involving bone – a three-phase bone scan is usually the first investigation. if the bone scan does not show the typical abnormalities as suspected in infection – the bone scan is diagnostic and further infection imaging is not needed. This would include suspected infected joint prostheses or osteomyelitis. Please also see bone scan procedure information here

 

Labelled White blood cells:

Your blood will be drawn and your white blood cells “labelled” with a radioactive tracer. Your own blood will then be re-injected into your veins.

White blood cells are the soldiers of our bodies and fight off infection when we are sick. If we have an infection these white blood cells will clump together to try to kill off the infection. When we re-inject your radioactive white blood cells we are able to see where those white blood cells go – indicating where the site of infection is. This can then often guide your clinician on further appropriate therapy. The radioactive white blood cells accumulate in areas where there is an active infection.

Images will be done at 30 minutes, 3 hours and 24 hours.

Please note that STRICLY ASEPTIC techniques are used when working with your blood and blood products. Strong Quality control measures are in place to ensure a very high standard of care.

For the doctors: please ensure that the patient has a large patent vein for venous access – as we need a good flow of blood when we draw blood. If the patient does not have good veins, we please ask that you place a CVP. Please also send a report with the patients newest white blood cells with the request.

 

F-18 FDG PET/CT (Fluorine-18 Fluoro-deoxy glucose positron emission tomography) :

PET/CT is also a nuclear medicine imaging technique but uses a different type of camera (PET/CT) and a slightly different type of radioactivity (positron emissions). The most common use for F-18 FDG PET/CT is in cancer imaging, but it is also very sensitive and a valuable tool in the diagnosis of infection.

F-18 FDG was the first PET tracer and is still the most commonly used PET/CT tracer in the world. Fluoro-deoxy glucose (FDG) is a molecule very similar to normal glucose. It is therefore absorbed by cells that use glucose as part of their metabolism. It is known that cancer cells are more metabolically active because they divide faster than normal cells and therefore use more glucose. This is one of the reasons that radioactive glucose accumulates faster and in higher concentration cancer cells. Many, various types of cancer cells show an increased rate of glucose use and this is one of the reasons why F-18 FDG is such a versatile and commonly used tracer in PET/CT imaging worldwide.

Although some types of cancer show low or no FDG uptake, we as specialists in the field have been trained to know when FDG would not be a suitable tracer.

The injection is completely safe, even in diabetics as it does not have any influence on your sugar level.

The advantage of using PET/CT is that because we look at a metabolic level, changes can be seen earlier than anatomical changes.