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Bone Scan
A bone scan is a technique used to produce pictures of
bones by first injecting a radioactive liquid substance into
the body and then using a receiver to detect radioactive
particles sent out by the body. See the next question for a
description of radioactivity.
WHAT IS RADIOACTIVITY?
Radioactivity is a property of nuclei (the center parts of
atoms) in which they break up and send out rays or
particles known as radiation. Atoms are the smallest part of
an element that can exist alone or in combination with
something else. Atoms are so small that they cannot be
seen even with high-powered equipment. A radioactive
substance is a substance that sends out radiation.
A bone scan.
FEATURED BOOK: Bones: Skeletons and How They Work
WHAT ARE THE SPECIFIC STEPS INVOLVED IN A BONE SCAN?
To begin with, the patient arrives 3 hours before the bone scan to be injected with a small
amount of the radioactive substance. The radioactive substance is attracted to bones
and attaches to a material in the bones that is similar to calcium (a metallic element). The
radioactive substance is usually injected into a vein (a blood vessel that carries blood to
the heart) in the arm. However, the radioactive substance may be injected through
another area in the body, especially if veins in the arm are difficult to find. Only one
injection of the radioactive substances is needed.
"Where Medical Information is Easy to Understand"™
After being injected, the patient is asked come back in three hours
so that the radioactive substance has enough time to travel
throughout the body and be absorbed by the bones. The patient will
be asked to drink five to eight cups of water before returning for the
bone scan. The patient will also be asked to urinate (pee) before the
exam. This helps to get rid of the radioactive substances that were
absorbed by soft tissues of the body and leads to better pictures.
When the patient returns for the bone scan, he/she lies down on a
table after removing metal objects and putting on a gown. A device
known as a gamma camera slowly moves over the body and scans
it to detect radioactive particles sent out from the radioactive
substance in the body.
There is also a gamma camera below the body that scans it as well. In most cases, the gamma camera
moves from head to toe to scan the entire body.
The patient must not move the body part that is being scanned. The examiner may ask you to change
positions during the exam. After collecting the information on the amount of radioactive particles sent out
from the body, the information is sent to a computer that produces a picture of the body, like this:
Bone scans are also capable of producing images in three dimensions (length, width, and depth
combined).
WHY DO PEOPLE GET BONE SCANS?
Most likely, a doctor asks a patient to get a bone scan if he/she is complaining of bone pain. The doctor is
using the bone scan to try and find out if you have:
Malignant and benign tumors (abnormal tissues that grow more rapidly than normal). Malignant tumors are
typically invasive, destructive, and spread to other areas of the body. Non-malignant tumors are described
as benign (pronounced bee-nine).
Broken bones, such as small breaks not seen on an x-ray.
Inflammation in bones.
Bone infection.
Bone scans are also used to monitor patients over time to see if there are any changes in response to
treatment for one of the conditions mentioned above.
IS A BONE SCAN PAINFUL?
No. A bone scan is not painful. The only pain that may be experienced is before the bone scan, when a
needle is injected into a vein.
WHO INTERPRETS THE BONE SCAN?
A type of doctor known as a nuclear medicine physician will analyze the results and interpret the bone
scan.
HOW DOES THE DOCTOR KNOW IF MY BONE SCAN IS NORMAL OR ABNORMAL?
Normal bones will absorb the radioactive substance in equal amounts throughout the body. When bone
formation occurs faster than bones around it, the bones that are forming quicker will absorb more of the
radioactive substance. The bone scan will produce pictures of the bones in colors that reflect how much
radioactivity was absorbed by them. In this way, the doctor can tell if there are any abnormalities in the
bones.
Areas of increased activity on bone scans appear dark and are known as "hot spots." The conditions
mentioned above (bone cancer, bone infections, and bone breaks) lead to hot spots because they cause
higher amounts of bone formation when compared to normal bones. Areas where the bone absorbs less of
the radioactive substance appear light and are known as cold spots. If you happen to see a picture of
your bone scan on the computer, be sure to remember to leave the interpretation up to the doctors.
CAN THE BONE SCAN RESULTS TELL WHAT IS CAUSING AN ABNORMAL FINDING?
No, a bone scan is not specific as to the cause of an abnormal finding. If there is an abnormality on a
bone scan, it is not possible to tell from the results whether the abnormality is due to cancer, a bone
break, or some other cause. For this reason, abnormal bone scans are usually followed by other types of
scans known as Computerized Axial Tomography (CT) or magnetic resonance imaging (MRI). CT and MRI
scans are often able to identify what is causing an abnormality. X-rays may also be requested.
CT (computerized tomography) scanning is an advanced imaging technique that uses x-rays and computer
technology to produce more clear and detailed pictures than a traditional x-ray. MRI scans produce
extremely detailed pictures of the inside of the body by using very powerful magnets and computer
technology.
CAN A BONE SCAN TELL THE DIFFERENCE BETWEEN AN OLD BONE BREAK AND A NEW BONE
BREAK?
A bone scan can tell the difference between an old bone break and a new bone break if the old bone break
is healed and is not growing at a rate higher than the surrounding bones. New bone breaks have
increased growth of bone because they are trying to reform, and these are easily detected by a bone
scan.
HOW DO I FIND OUT THE RESULTS OF THE BONE SCAN AND HOW LONG DOES IT TAKE?
The results of the bone scan will be provided to you by the doctor that referred you to get the test. This
process can be speeded up if the place where you got the bone scan sends the results and images to
your doctor over the Internet. It may take a few days to a week to get the bone scans results, depending
on how busy the doctors are that read the scans. Test results can be obtained the same day if the
referring doctor orders that it be done stat, which is hospital jargon meaning “immediately.”
ARE THERE ANY SIDE EFFECTS FROM BEING INJECTED WITH A RADIOACTIVE SUBSTANCE FOR
A BONE SCAN?
Believe it or not, there are actually no side effects associated with being injected with the radioactive
substance used for a bone scan. The body absorbs less radiation during a bone scan than during an x-
ray.
AM I BEING EXPOSING TO MORE RADIATION IF THE DOCTOR TAKES MANY PICTURES?
No. When the camera moves over your body, it is measuring radiation and not exposing the patient to it.
The patient is exposed to radiation during the injection and at no other time. So whether the doctor takes
1 picture or 1000 pictures after the injection, you have still been exposed to the same amount of radiation.
HOW LONG DOES IT TAKE FOR THE RADIOACTIVE SUBSTANCE TO LEAVE MY BODY?
The radioactive substance used in bone scans is usually gone from the body in one to two days.
HOW LONG DOES A BONE SCAN TAKE?
A bone scan usually takes about 30 minutes to an hour, depending on the size of the patient's body. If only
a certain part of the body is being scanned, this may take 20 to 30 minutes.
WHY SHOULD I GET A BONE SCAN INSTEAD OF AN X-RAY?
Unlike an x-ray, bone scans can detect changes in function before changes in structure. For example, a
bone scan can detect signs of infection (due to increased activity in the bones) before the bone appears
damaged. X-rays cannot do this.
CAN I EAT ANYTHING AND TAKE MY MEDICATIONS BEFORE OR AFTER A BONE SCAN?
Yes to both. You can eat as you normally do and take your medications before and after a bone scan.
WHAT ARE REASONS THAT CAN PREVENT ME FROM GETTING A BONE SCAN?
Pregnancy, breast feeding, and certain types of allergies can prevent someone from getting a bone scan.
You should discuss this with your doctor if it relates to you.
