Explain the non safe or harm aspects of CT scan on the patient,, particularly after multiple CT scans done for one patient. mentioned essentially the risk of cancer in later life, which reach 1/2000. Also, mentioned the organs, age group, and gender which affected more by CT radiation Finally , stressing on eliminating CT scan as possible

1. Safety of CT Scan?!
Dr.Hisham Abid Aldabbagh
MSc. Internal Medicine
Kingdom of Saudi Arabia
Ministry of Health
Directorate of Health
Affairs in Gurayat
Gurayat General Hospital

2. Essentials
The Lancet 2012,
• CT is one of the most valuable medical imaging techniques
when used justifiably.
• A number of professional organizations have provided
appropriateness criteria or referral guidelines to achieve
appropriate use.
• Ionizing radiation used in CT can have side effects such as a
potentially increased risk of cancer in later years.

3. • In December 2011 the Institute of Medicine (IOM),USA
published a report concluding that ionizing radiation
contributes more to the development of breast cancer than
any other type of routine environmental exposure.
• CT scanners emit X rays. Different tissue types absorb X rays
in varying amounts, and the resulting contrasts provide
detailed images of anatomy and disease.
• Absorbed radiation can break chemical bonds in tissues,
li erati g harged io s he e the ter io izi g
radiatio that a da age DNA a d produ e a er
should cells be unable to repair themselves

4. With current knowledge,
• There is no controversy on carcinogenic
effects for organ doses in excess of 100mGy, (which can (acc
(obtained in 5 to 15 CT scans).
• The controversy remains about cancer risk from a single or a
few CT scans.
• The new research reinforces the belief of major international
organizations about cancer risks from a few CT scans. The risk
is very low but appears to be real, not hypothetical

5. Risk Estimates
FDA, 2015
• A CT examination with an effective dose of
10 millisieverts (abbreviated mSv*; 1 mSv = 1 mGy in the
case of x rays.) may be associated with an increase in the
possibility of fatal cancer of approximately 1 chance in 2000.
This small increase in radiation-associated cancer risk for an
individual can become a public health concern if large
numbers of the population undergo increased numbers of
CT screening procedures of uncertain benefit.
* The standard unit in the International System of Units (SI) of dose equivalent having the
same biological effect as one joule of x-rays perkilogram of recipient mass (or one gray)

7. The most Important correlated questions
1. Are CT examinations associated with higher radiation doses?
• Yes. All CT examinations deliver higher radiation doses. The
effective dose from CT scans may range from approximately 2
to 20 mSv.
• A CT scan with a dose of 10 mSv is equivalent to 500 chest X
rays assuming a dose of 0.02 mSv per chest X ray .
• Perfusion CT, some CT-guided
interventional procedures
and some specialized procedures
requiring several successive CTs
can deliver even higher doses than 20 mSv.

8. 2. How many CT examinations are unsafe?
• There is no straight answer to this question in terms of
specifying a number.

9. 3. Does the patient need yet another CT examination?
• You can help avoid unnecessary repeat examinations by
keeping the results of your previous examinations (X
ray, CT, MRI, ultrasound and other imaging
examinations) safely , not all repeat investigations can be
avoided as it may be sometimes appropriate.
• Also a CT examination sometimes involves the injection
of an intravenous contrast agent. Imaging can be
performed at multiple time points before and/or after
the injection of the contrast material.

10. 4. Can a patient undergo a CT scan while she is pregnant?
• CT scan in pregnancy is not forbidden, but if the same
information can be obtained from another examination that
does not require the use of ionizing radiation, it should be
preferred.
• If a CT examination requires direct exposure of the pelvic
region and the unborn child will be in the direct path of the X
ray beam, the examination may still be possible if it is
essential to save life or is justified on special consideration of
risks and benefits. The doctor might consider delaying the CT
examination or using an alternative examination such
as ultrasound or MRI.

11. • If CT examination is duly justified, then every effort should
be made to optimize so as to perform the examination with
minimal radiation dose to the fetus e.g. choosing lower
exposure factors and providing shielding where appropriate.
• If the abdomen or pelvis is not being imaged, such as in chest
or head CT, then there is no risk to the baby.
• The goal, however, is to take care of the mother, who has a
much greater chance of developing a serious illness, such as
appendicitis

12. . Should I be concerned about radiation if I prescribe for a5
child?
• Not really if the examination has been fully justified based
on risk and benefit considerations.
• But it is necessary to establish this by discussion with the
parents that their child needs the CT scan and why it cannot
be replaced by another examination like ultrasound or MRI.

13. body CT screening?-. Should I ask for a whole6
• No. There is a lack of evidence demonstrating that
whole-body CT screening of individuals without
symptoms is beneficial.

14. 8- Does radiation risk depend on age?
• Yes, when given equal radiation doses, the risks for children
and adolescents are greater than for adults.
• Children grow quickly, and their cells are more sensitive to
radiation.
• Since effects of radiation take years to develop, their youth
extends the time for any potential effects from ionizing
radiation to occur.
• As adults age, radiation exposure becomes less of a concern.
The body tissues of older patients are less sensitive to the
effects of radiation.

15. 9-Does radiation risk depend on gender?
• Many studies have found that a number of major illnesses are
influenced by gender. The same holds true for the potential
risks associated with exposure to x-rays or radiation from
radioactive materials(ionizing radiation).
• For example, female breasts are more sensitive to ionizing
radiation than male breasts.
• While men can develop breast cancer, it is extremely rare.
• The risk for radiation-induced breast cancer in men is
negligible

16. • Females have a higher risk of radiation-induced:
• Lung cancer
• Thyroid cancer
• Breast cancer

17. certain organs more sensitive to radiation exposureAre-10
than others?
• There are differences in organ sensitivity to radiation. For
example, the breasts, thyroid, lungs, and bone marrow are
more sensitive to radiation because the cells in those areas
divide rapidly. Less-sensitive organs include the brain,
where cells do ’t divide as quickly.

18. Some correlated studies
• Multiple CT Scans and Cancer Risk
WebMD Health News, 2009
• According to a study, the findings confirm a modest but
clinically significant increase in cancer risk associated
with multiple CT scans.
• Using a cancer risk assessment model, the researchers
found that 7.3% of the study participants had an
elevated risk of cancer because of radiation from CT
scans.

19. • CT Overuse a Concern
• WebMD 2009
• It is lear that CT is ei g o erused, so eti es patie ts put
pressure on the physicians to order CTs, but physicians must be
a are of the appropriate i di atio s for orderi g the .
• The American Heart Association issued an advisory to
physicians warning against the use of CT scans to screen
asymptomatic patients.
• The physicians often have no idea how many previous scans a
patient has had.
• Some scientists are developing a computerized program that
keeps track of the total number of scans a patient has had and
also quantifies the risk.

20. • It is estimated that anywhere from 5% to 30% of CT exam
may be medically unnecessary

21. It is recommended to ask yourself these three questions if
you order a CT scan:
• 1. Is this scan really going to change how you treat
patient?
• If the answer is no, the test may not be necessary..
• 2. Is there a alter ati e that does ’t ha e a radiatio
risk?
• Ultrasounds and MRIs are great ways to diagnose certain
conditions.
• 3. What dose of radiation will the patient receives?

23. FDA cites 2 basic principles for decreasing CT radiation risks
• One is justification, which refers to prescribing a CT exam
only when it is medically necessary; and the benefit
outweighs any associated risk.
• The other is optimization, which refers to adjusting and
operating a CT scanner so that images adequate for
diagnosis are obtained at the lowest possible dose.

24. • The American College of Radiology (ACR) and other medical
professional organizations have recommended refere e
le els for some medical imaging exams. Reported as CTDI,
these levels represent upper-bound radiation exposures for
specific medical indications that should ’t be exceeded
among individual patients.
• Hospitals must record in an electronic database the dose
(as either CTDI or DLP) of every CT scan given. In addition,
the scanner output must be reviewed once a year by a
medical physicist.

26. Innovation
• Starting Radiation Dose Tracking in GGH
- Initially, by manual registration, to calculate the total
radiation doses a patient has exposed through his or
her life, and then taking the most appropriate decision
for patients with higher total doses to protect them
against additional extra doses through qualified
coordination with all health professional team
members who are dealing with a given patient
- Secondly, Electronic registration of radiation doses for
easier and more accurate estimations and follow up

27. Conclusional Message
Dear Colleagues,
Please,
• Consider the unsafety aspects of CT scan when you order it
• Take seriously with caution all CT scans for children
• Clear always the justification and the optimization of all CT
scans you ordered
• Think about the long term accumulative adverse effects of
CT scans, particularly carcinogenic effect

28. How would you Share in Eliminating
Unnecessary CT Scans ??
Thank You
I will be so happy to share with you
Email: dr.hishamdabbagh@gmail.com