Medically reviewed by Dr. Numair Younis, M.B.B.S. (K.E.M.U.), FEBNM European Fellowship in Nuclear Medicine, Consultant Nuclear Medicine Physician, Al-Nasar Lab & Diagnostic Centre. Updated August 2026.
Quick answer: Nuclear medicine scans use a tiny amount of radioactive tracer to show how an organ is working, not just how it looks. A bone scan detects bone disease across the whole skeleton. A thallium scan checks blood supply to the heart muscle. A DTPA renal scan measures kidney function and drainage.
Book a nuclear medicine scan: call 0300 0341944 or request an appointment here.
What is nuclear medicine?
Nuclear medicine is a branch of imaging that works in the opposite direction to an X-ray. Instead of sending radiation through the body from outside, a very small quantity of a radioactive tracer is given, usually by injection. The tracer travels to a specific organ, and a gamma camera detects the signal it gives off.
This matters because the resulting image shows function. A CT or MRI tells you what a structure looks like. A nuclear medicine scan tells you how well it is working, which often reveals disease earlier, before any change in shape has appeared.
How do nuclear medicine scans compare?
| Scan | What it examines | Common reasons for referral | Approximate time |
|---|---|---|---|
| Bone scan | The whole skeleton | Cancer spread to bone, hidden fractures, bone infection, unexplained bone pain | Injection, then imaging 2 to 4 hours later |
| Thallium scan (myocardial perfusion) | Blood supply to heart muscle | Chest pain, suspected reduced blood flow, assessment after a cardiac event | Stress and rest imaging, often 3 to 4 hours total |
| DTPA renal scan | Kidney function and drainage | Suspected obstruction, differing function between kidneys, GFR measurement | Roughly 30 to 45 minutes |
| DMSA renal scan | Kidney tissue and scarring | Scarring after infection, particularly in children | Injection, then imaging 2 to 3 hours later |
What does a bone scan show?
A bone scan images the entire skeleton in one study, which no other single test does as efficiently. The tracer collects wherever bone is actively repairing or remodelling, so areas of increased activity appear as bright spots, often called hot spots.
It is most often used to check whether a known cancer has spread to bone, to find stress fractures that do not appear on plain X-ray, to investigate suspected bone infection, and to assess unexplained bone pain. Because it looks at the whole body, it can find a problem in a site nobody suspected. Read more about bone scan testing in Lahore.
What is a thallium scan and how does it work?
A thallium scan, also known as myocardial perfusion imaging, assesses whether the heart muscle is receiving enough blood. Images are taken in two states: once when the heart is under stress, either through exercise or a medicine that mimics it, and once at rest.
Comparing the two sets is what makes the test powerful. An area that receives less tracer under stress but normal tracer at rest suggests a narrowed artery limiting flow when demand rises. An area that is reduced in both may indicate muscle already damaged by a previous heart attack. See our thallium scan page for details.
What does a DTPA renal scan measure?
A DTPA renal scan follows a tracer as it is filtered by the kidneys and drains into the bladder. It answers questions a blood test cannot: how much each kidney is contributing individually, and whether urine is draining freely or being obstructed.
This split function measurement is important before kidney surgery, in suspected obstruction, and in children with recurring urinary infections. It also provides a measured GFR, the standard indicator of kidney filtration. Read more about renal scans at Al-Nasar Lab.
Are nuclear medicine scans safe?
Yes, for the great majority of patients. The radiation dose from a typical nuclear medicine study is comparable to that of many CT scans, and the tracer is chosen to clear from the body quickly, usually within about 24 hours. Drinking plenty of water afterwards helps flush it out.
Allergic reactions to the tracers are very rare because the quantities involved are minute. Tell the department if you are pregnant or breastfeeding, as timing or alternatives may need to be arranged, and mention any recent scans that used contrast or other tracers.
How should you prepare?
- Bone scan: no fasting. Drink plenty of water between the injection and the imaging, and empty your bladder before the scan starts
- Thallium scan: avoid caffeine, including tea, coffee and cola, for at least 12 to 24 hours, since caffeine interferes with the stress agent. Fasting and pausing certain heart medicines may be advised
- DTPA renal scan: drink water beforehand so you are well hydrated, unless instructed otherwise
- All scans: bring previous reports and imaging, wear clothing without metal, and allow for waiting time between injection and imaging
Nuclear medicine at Al-Nasar Lab
Al-Nasar Lab & Diagnostic Centre provides nuclear medicine services at its main Johar Town campus, the full service site where bone scans, thallium scans and renal scans are performed alongside CT, MRI and ultrasound. Studies are reported by qualified consultant radiologists, and because the department sits within a full imaging centre, follow up scans can usually be arranged in the same place.
Find your nearest branch, explore our full range of tests, or call 0300 0341944 to book.
Frequently Asked Questions
How much does a bone scan or thallium scan cost in Pakistan?
Pricing varies by scan type and centre. For current Al-Nasar Lab pricing, call 0300 0341944 or see the individual scan pages linked above.
Will the radioactive tracer make me radioactive?
Only very slightly, and only briefly. The tracer decays and is passed out of your body within roughly a day. As a precaution you may be advised to limit close contact with pregnant women and young children for a few hours afterwards.
Why do I have to wait hours between the injection and the scan?
The tracer needs time to travel to the target organ and collect there. Imaging too early gives an unclear picture. For a bone scan this uptake period is typically two to four hours, and you are usually free to leave and return.
Is a bone scan better than an MRI for bone problems?
They serve different purposes. A bone scan surveys the whole skeleton and detects activity anywhere. An MRI gives far greater detail of one specific area. Doctors often use a bone scan to locate a problem and an MRI to examine it closely.
Can I eat before a nuclear medicine scan?
For a bone scan or DTPA renal scan, yes. For a thallium scan you will usually be asked to fast for a few hours and to avoid caffeine beforehand. Always follow the specific instructions given when you book.
This article is for general information and is not a substitute for medical advice. Please discuss your scan and results with a qualified doctor.
