ONSIGHT 3D EXTREMITY SYSTEM
Frequently Asked Questions
What is a Cone Beam CT (CBCT) extremity exam?
A cone beam CT scan is a noninvasive diagnostic procedure that uses an
advanced x‐ray technology to produce detailed 3 dimensional
cross‐sectional images of your extremities.
What is it used for?
The surgeon will order a CBCT exam to help diagnose and treat a variety
of conditions of the bone and soft tissue in upper and lower
Does it hurt?
No. The CBCT exam is painless.
How long will it take?
The actual scan will take about 25 seconds but the complete exam,
including getting you positioned, will be about 15 minutes. However, our
experience at Resurgens has been ~10 mins.
Do I have to be still during the exam?
Yes, while the scan is taking place you will need to remain still. The
OnSight system has a patient display monitor that counts down the
scanning time so you can easily see the time left in the exam. For
standing exams, there are immobilization accessories and patient support
handles to help you remain still during the scan.
I don't like being in small spaces. Does the CBCT system enclose my entire body?
No, only the effected body part is placed in the imaging bore. The OnSight system also has a patient access door so you can easily step into and out of the system for standing exams.
I have metal in my extremity. Can I safely get a CBCT exam?
Yes, there is no issue with getting a CBCT exam with metal in your
extremity but you should let the technologist know of the presence of
metal. The OnSight system is equipped with special software to reduce
the artifacts associated with imaging metal.
What is the difference between CBCT and a traditional X‐ray?
Both procedures use X‐rays. A traditional X‐ray produces a 2 dimensional
view of the extremity whereas a CBCT exam produces a 3 dimensional
image providing significantly more information to your surgeon.
What are some other differences between CBCT and a traditional CT?
While both of these equipment types fall into the computed tomography
(CT) category, there are some big differences between them. Traditional
CT exams are performed with the patient lying on an imaging table that
is moved through the bore of the CT machine. As the table moves through
the bore, individual slices of the anatomy are captured and used to
create a 3 dimensional image of the anatomy.
In a CBCT scan, the part being imaged is positioned in the system and images of the complete anatomy are captured in a single rotation. One of the advantages of a CBCT scan over a traditional scan is examinations of the lower extremity joints can be perform under the patient's natural load. This allows the surgeon to get important information that they couldn't obtain in a traditional CT exam. The result is a 3 dimensional data set that your doctor will use to make a proper treatment path.
The radiation dose is also lower with a CBCT scans as only the affected limb is imaged.
How does the X‐ray exposure compare to traditional CT?
In a CBCT exam, only the affected limb is imaged while in a CT exam,
typically the non affected limb also gets imaged. In this scenario, the
radiation exposure is reduced by 50% when imaged on the OnSight System.
How do I prepare for the CBCT exam?
Wear comfortable, loose‐fitting clothing to your exam. You may be given a
gown to wear during the scan. Metal objects including jewelry may
affect the exam and should be left at home or removed prior to your
Who performs and interprets the CBCT exam?
A registered CT technologist or radiologic technologist will perform
your exam. A radiologist or your surgeon will interpret the CBCT exam.