How does CT work?
CT uses X-rays to create pictures of inside your body. Unlike an X-ray, which just provides a single image like a
picture, CT produces a 3D volume of data, allowing the Radiologist (specialist imaging doctor) to view images
from any position or angle.
Do I need to book?
Bookings are preferred, however we do have a daily list for urgent studies available, and if you are happy to sit
and wait we may be able to fit you in without a booking.
How is the test performed?
You will need to lie on a bed that moves in and out of a circular area several times. You may be asked to hold
your breath and listen to the machine. Some studies require an injection of intravenous contrast to get the best
images. Rarely we may ask you to drink oral contrast for 2 hours before having your scan.
What preparation is required?
This depends on the study. If you require intravenous contrast you will be asked to drink water for 1 hour before
your study. If we are looking at your kidneys or urinary bladder you will be asked to hold your bladder, and not
go the toilet for 1 hour prior to the study, so that we get the best pictures.
Do I need to fast?
Generally no, however it is best to avoid food for 2 hours prior to the study if it requires contrast.
What is intravenous contrast?
Contrast is a safe, clear liquid that is injected into your arm during the test. When we scan your body the
contrast is very bright, and we use it to highlight certain areas. This allows us to get much more information,
and helps us detect and diagnose more conditions.
What is oral contrast?
Oral contrast is a liquid you drink approximately 2 hours before your study to help highlight portions of your
bowel. Generally it is not required, however for very young patients looking for appendicitis or patients that
have had recent surgery we may require it.
Do I need intravenous contrast?
Some studies do not require contrast to answer your doctors questions, however some studies cannot be
done without contrast. In between these two extremes there are tests where contrast is preferred to get the
most information, however the test can be done without it. As a rough guide, approximately half of the studies
we perform involve intravenous contrast.
How do you decide who needs contrast?
The decision to recommend contrast is based on multiple factors including your age, the test requested, and
your clinical notes.
What are the risks of intravenous contrast?
The two main risks are that a very small percentage of the population may have an allergic reaction to the
contrast, and that it can cause a temporary reduction in your kidney function.
What is the risk of an allergic reaction?
The risk of a severe reaction is very low, approximately 0.04% ( 1 in 2500). The risk of a mild reaction is
approximately 0.5% (1 in 200), and this is generally mild skin itching or lumps. We have a trained specialist
doctor (Radiologist) on site whenever contrast is administered to treat these reactions. Treatment may be in
the form of an oral tablet (antihistamine, hayfever tablet) ranging to the administration of adrenaline and
other measures.
What if I've had a contrast reaction before?
If you have had a previous reaction, you are at an increased risk of having another reaction, and this can be
more severe. In this case, we will generally perform the study without contrast. While it may be inconvenient, if
you do require a study with contrast, this is best performed at a hospital.
Do you use premedication?
The latest evidence suggests that premedication is not useful in preventing a contrast reaction, which is why
we don't give it. For more information see here: https://pubs.rsna.org/doi/10.1148/radiol.2021210490
What are the risks of radiation?
The main risk is that in high doses radiation can cause cancer, however the diagnostic doses we use are very
small, and we use the minimum dose we can for every patient. Every day you are exposed to natural radiation
coming from space and natural sources on earth, which all contribute to your lifetime risk of cancer of 42%.
The risk of not having the test includes missing a diagnosis or delaying treatment.
What is the weight or size limit for the scanner?
Our scanner has a weight limit of 200kg. In addition the circular area your body needs to pass through has a
diameter of 70cm and a circumference of 200cm.
Can I have contrast if I have diabetes?
The main risk with diabetes is that your kidneys may not be working as well as they could. We will check your
kidney function before the test to make sure that it is safe for you to have contrast if you require it.
Do I have to stop any medications before the test?
No. You should continue to take all of your normal medications. Previously patients have been asked to
withhold some medications before or after the test, however it is now considered safe to continue.
Can I have contrast if I am breastfeeding?
Yes. A very small amount of the contrast may be expressed in the breastmilk, however not enough to cause
any harm to your baby. Previously patients were asked to express the milk and discard, however this is no
longer the protocol.
Can I have a CT if I am pregnant?
Generally no. While the risk of harm to an unborn child is very low with most studies, it is best avoided.
I am claustrophobic - can I have a scan?
The scanner is quite open, and most patients tolerate it well. We are happy for you to come in and see the
room first before proceeding.
Do you offer sedation for scans?
No.
Where can I get more information?
You can get more information here: https://www.insideradiology.com.au/computed-tomography/
Copyright 2021 Clearview Medical Imaging
COMPUTED
TOMOGRAPHY
(CT)
COMPUTED TOMOGRAPHY (CT)
IS AN ADVANCED IMAGING
TECHNIQUE TO PROVIDE HIGH
RESOLUTION IMAGES
This scan produces images of almost any part of the body with
a resolution of less than 1mm. We use the latest techniques to
acquire the images, and report the findings using the most
up-to-date guidelines. Every scan is different, and is tailored
to your individual circumstances.
A Carlisle Health Clinic
How does CT work?
CT uses X-rays to create pictures of inside your
body. Unlike an X-ray, which just provides a
single image like a picture, CT produces a 3D
volume of data, allowing the Radiologist
(specialist imaging doctor) to view images from
any position or angle.
Do I need to book?
Bookings are preferred, however we do have a
daily list for urgent studies available, and if you
are happy to sit and wait we may be able to fit
you in without a booking.
How is the test performed?
You will need to lie on a bed that moves in and
out of a circular area several times. You may be
asked to hold your breath and listen to the
machine. Some studies require an injection of
intravenous contrast to get the best images.
Rarely we may ask you to drink oral contrast for
2 hours before having your scan.
What preparation is required?
This depends on the study. If you require
intravenous contrast you will be asked to drink
water for 1 hour before your study. If we are
looking at your kidneys or urinary bladder you
will be asked to hold your bladder, and not go the
toilet for 1 hour prior to the study, so that we get
the best pictures.
Do I need to fast?
Generally no, however it is best to avoid food for
2 hours prior to the study if it requires contrast.
What is intravenous contrast?
Contrast is a safe, clear liquid that is injected
into your arm during the test. When we scan
your body the contrast is very bright, and we
use it to highlight certain areas. This allows us to
get much more information, and helps us detect
and diagnose more conditions.
What is oral contrast?
Oral contrast is a liquid you drink approximately
2 hours before your study to help highlight
portions of your bowel. Generally it is not
required, however for very young patients
looking for appendicitis or patients that have
had recent surgery we may require it.
Where can I get more information?
Do you offer sedation for scans?
No.
I am claustrophobic - can I have a scan?
The scanner is quite open, and most patients
tolerate it well. We are happy for you to come in
and see the room first before proceeding.
Can I have a CT if I am pregnant?
Generally no. While the risk of harm to an
unborn child is very low with most studies, it is
best avoided.
Can I have contrast if I am breastfeeding?
Yes. A very small amount of the contrast may
be expressed in the breastmilk, however not
enough to cause any harm to your baby.
Previously patients were asked to express the
milk and discard, however this is no longer the
protocol.
Can I have contrast if I have diabetes?
The main risk with diabetes is that your kidneys
may not be working as well as they could. We
will check your kidney function before the test to
make sure that it is safe for you to have contrast
if you require it.
Do I have to stop any medications before
the test?
No. You should continue to take all of your
normal medications. Previously patients have
been asked to withhold some medications
before or after the test, however the lastest
evidence suggests it is safe to continue.
What is the weight or size limit for the scanner?
Our scanner has a weight limit of 200kg. In
addition the circular area your body needs to
pass through has a diameter of 70cm and a
circumference of 200cm.
What are the risks of radiation?
The main risk is that in high doses radiation can
cause cancer, however the diagnostic doses we
use are very small, and we use the minimum
dose we can for every patient. Every day you are
exposed to natural radiation coming from space
and natural sources on earth, which all
contribute to your lifetime risk of cancer of 42%.
The risk of not having the test includes missing a
diagnosis or delaying treatment.
Do you use premedication?
The latest evidence suggests that
premedication is not useful in preventing a
contrast reaction, which is why we don't give it.
For more information see here:
https://pubs.rsna.org/doi/10.1148/radiol.2021210
490
What if I've had a contrast reaction before?
If you have had a previous reaction, you are at
an increased risk of having another reaction,
and this can be more severe. In this case, we will
generally perform the study without contrast.
While it may be inconvenient, if you do require a
study with contrast, this is best performed at a
hospital.
What is the risk of an allergic reaction?
The risk of a severe reaction is very low,
approximately 0.04% ( 1 in 2500). The risk of a
mild reaction is approximately 0.5% (1 in 200),
and this is generally mild skin itching or lumps.
We have a trained specialist doctor
(Radiologist) on site whenever contrast is
administered to treat these reactions.
Treatment may be in the form of an oral tablet
(antihistamine, hayfever tablet) ranging to the
administration of adrenaline and other
measures.
What are the risks of intravenous contrast?
The two main risks are that a very small
percentage of the population may have an
allergic reaction to the contrast, and that it can
cause a temporary reduction in your kidney
function.
How do you decide who needs contrast?
The decision to recommend contrast is based
on multiple factors including your age, the test
requested, and your clinical notes.
Do I need intravenous contrast?
Some studies do not require contrast to answer
your doctors questions, however some studies
cannot be done without contrast. In between
these two extremes there are tests where
contrast is preferred to get the most information,
however the test can be done without it. As a
rough guide, approximately half of the studies
we perform involve intravenous contrast.
Copyright 2021 Clearview Medical Imaging
COMPUTED
TOMOGRAPHY
(CT)
COMPUTED
TOMOGRAPHY (CT)
IS AN ADVANCED
IMAGING TECHNIQUE
TO PROVIDE HIGH
RESOLUTION IMAGES
This scan produces images of almost any part
of the body with a resolution of less than 1mm.
We use the latest techniques to acquire the
images, and report the findings using the most
up-to-date guidelines. Every scan is different,
and is tailored to your individual circumstances.
A Carlisle Health Clinic
