MDP bone scan

Downloads

For most essential points to best prepare for the procedure, please download the patient information brochure (PDF).
For a more elaborate explanation of the procedure and related points, please continue to read ahead.

Brief introduction

Principle

MDP stands for methylene diphosphonate.

Bone structure

Bone tissue consists of more flexible and organic part called 'ossein' or 'matrix' (~30% by mass) and the mineral or inorganic part (~70% by mass). Ossein largely consists of collagen fibres. Inorganic part largely consists of 'apatite' (a phosphate-containing molecule) and the metal calcium. The inorganic part tends to form crystals called 'calcium hydroxyapatite'.

Bone metabolism

Although bones are very strong and appear like solid permanent structures, in reality any bone is constantly added to (through cells called 'osteoblasts') and broken down (through cells called 'osteoclasts'). In a healthy state these mutually antagonistic processes are in a state of equilibrium, and are part of 'bone metabolism'.

How MDP binds to bone?

Newly formed (immature) bone tends to have more numerous but smaller hydroxyapatite crystals in contrast to the mature bone that has larger crystals. Smaller crystals of immature bone have overall greater surface area and empty sites for binding of molecules like MDP. In some of the disease processes, blood supply to the abnormal tissues around the bone is also increased. Thus, binding of MDP to bone is increased by: (a) presence of sites of immature bone, and (b) increased blood supply.

Sites of increased MDP binding

Tumours developing primarily in bone as well as those that would have developed following spread from cancers at other sites ('metastases') harbour large proportion of immature bone because of fast rate of bone formation. Same holds true for sites of recent as well as old fractures, bone infections and non-cancerous causes of excessive bone formation.

Indications (conditions in which advised)

Detecting metastasis from other cancers (most commonly, prostate, breast, lungs and kidneys).
Detecting metastasis from cancer in other bones.
Aiding diagnosis of bone infection.
Aiding diagnosis of infection versus loosening of joint replacement prostheses.
Confirmation of unilateral condylar hyperplasia (a condition causing deviation of the jaw bone to one side).

Considerations / steps before procedure

Prior appointment is a must.
Patient must not be pregnant.
If breast feeding, please inform the staff for further directions.
Please let the staff know at the time of appointment if the patient is unable to lie still for ~20 min, has breathing difficulty, or might need special medical attention for the duration of visit.
There is no need to hold urine.
You can have food and water before the scan.
Medications - if any - prescribed by your doctor are to be had as per schedule.
Wear loose-fitting but warm clothes.
Do not bring expensive jewellery or accessories along with you for the scan.
Proof of doctor's request is necessary for starting the procedure.
The patient must be accompanied by a responsible carer.

What to expect as part of procedure?

Important steps

Patient registration and consent.
Handing over medical documents to the staff.
MDP is injected into a vein (usually in the arm) over a few seconds, and the patient waits in the restricted waiting area.
Scanning starts 2.5 to 3 hours later, which involves patient lying on their back on the scanner table for ~20 min. During the procedure, the table moves such that the entire body is scanned from head to toe by a pair of stationary detectors.
Occasionally, a SPECT (3-dimensional scanning) acquisition may be done, which could take ~30 min. Likewise, a correlative non-contrast CT could also be acquired that takes ~5 min.

Discomfort / risks during procedure

Pain during injections or IV cannula insertion.
There is risk of extravasation at the time of injections or IV cannula insertion. [Extravasation means that blood leaks through the walls of vein punctured by cannula’s needle].

Time taken for the entire patient visit

Typical: 4 hours.
Be prepared for: 5 hours.

What to expect after procedure?

Precautions / special care

Maintain at least 1 metre-distance from pregnant ladies and children (below 10 years) for at least 5 hours after the scan.
Drink plenty of water throughout the day (3 to 4 litres).
Pass urine as frequently as possible throughout the day.

Discomfort / risks

There are no remarkable expected risks or side effects.

Time taken for report / summary generation

Typical (for self-paying patients): 12 hours.
Be prepared for: 24 hours.

Additional reading

For additional information, please visit the following links.

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