2 6 October 2003 KERALA CALLING
Medical X-rays:
A Note of Caution
Do you know that the British army
equipped its base hospitals in
England with X-ray equipment in
1898, when they learnt of its successful use
by Surgeon Major Bewoor in the NorthWest
Frontiers? Porters carried the accessories
to assemble the primitive x-ray unit, in 100-
pound boxes. They traveled over virtually
road-less terrain over 200 miles into the
Khyber Pass region.
(Late) Dr. K.P.Mody, an eminent
radiologist, noted that a chemist imported
the first X-ray unit into Bombay in 1902.
But medical colleges appreciated their
importance 16 years later. Lady Hardinge
Hospital in Delhi installed the first x-ray unit
in 1918. Over the past 100 years, the total
number in India grew into about 35,000 or
so.
In 1996, Government of Kerala set up
the Directorate of Radiation Safety (DRS)
as an independent agency directly under the
Secretary, Department of Health and Family
Welfare (DH & FW) to enforce AERB
guidelines on medical x-ray installations in
Kerala. AERB has delegated legal authority
to DRS to inspect x-ray installations in
Kerala.
I was a member of the specialist
committee, which prepared a technical report
outlining the constitution and functions of
DRS.
The State Government instituted a truly
innovative legal process to control medical
x-ray installations by amending the Electricity
Rules. DRS is a shining example of the
initiative taken by Kerala Government and
is a model for other States to emulate. DRS
has performed creditably in carrying out its
mandate.
Specialists agree that physicians should
recommend medical X-ray examinations only
on the basis of qualified clinical judgement.
Well-trained professionals should carry them
out with the help of optimally adjusted
equipment. They are then the most beneficial
life saving procedures, we know of today. If
that is so, is there any need for caution?
There is irrefutable evidence that high
doses of ionizing radiation are harmful to
man. But most of the medical diagnostic xray
procedures expose patients to relatively
low doses. We do not know conclusively
whether low doses are harmful or not. Since
we prudently assume that even small doses
can cause some harm, physicians should, in
any x-ray examination, expose their patients
to doses as low as reasonably achievable
without losing clinical benefit.
Physicians role in assuring safety
Physicians have an important role in
ensuring safe use of x rays. Regrettably, some
physicians order X-ray examinations
routinely. X-ray examinations at times
degrade into a comforting ritual! Physicians
should carry out medical X-ray procedures
only if they give them useful information to
treat the patient.
Physicians should buy only AERB
approved x-ray equipment. They should
comply with all the radiological safety
requirements. . They must use protective
accessories such as gonadal shields, mobile
protective barriers, lead aprons, etc, and
motivate workers to use these accessories.
Extra care should be taken when a
pregnant or a potentially pregnant woman is
x-rayed. They must ask whether the patient
is pregnant or not. A clinically indicated
examination need not be avoided simply
because of the implied risk from x-ray
exposure. Physicians must use optimally
adjusted equipment, employ appropriate
technique factors and carry out the
procedures with as low a dose as is reasonably
achievable.
On April 26, 2002, the US Food and
Drug Administration (USFDA) noted that
some medical imaging facilities in USA
promote and market whole body CT
scanning or screening as a preventive or
proactive health measure to healthy
individuals who have no symptoms or
suspicions of disease. FDA warns that for a
person without symptoms, CT screening may
not reveal serious disease and the potential
harm to the individual may be greater than
the presumed benefit.
CT is a unique tool to diagnose disease,
trauma or abnormality and to plan, guide and
monitor treatment. But it must not to be
used indiscriminately.The dose received by a patient during
a CT procedure is generally much larger that
that from most conventional X-ray
procedures.
In 2001, the American Journal of
Radiology published eight articles related to
radiation doses in CT scan examinations. The
journal noted that many CT scan centres in
USA use the same technique factors while
examining adults and children. Children then
receive significantly greater radiation doses
than adults without any additional clinical
benefits. Children are more sensitive to
radiation than adults.
I brought the US FDA advisory which
contained recommendations to reduce
radiation risk from computed tomography
to children and small adults to the notice of
over 400 CT scan users in India. I understand
that some radiologists in Kerala implemented
the advice from USFDA. For instance,
Dr.P.Rajendran, Associate Professor,
Department of Radiology, Calicut medical
college informed me that acceptable CT
images are possible with nearly half the
radiation dose. Parents may ask the
radiographer whether he uses different
technique factors while x-raying children and
small adults.
Role of the public
Many patients are satisfied only if their
physicians recommend an x-ray examination
as part of the medical diagnosis. They tend
to believe that no examination is complete
unless they have been x-rayed! Patients must
leave it to the physician to decide.
Crowding near and inside an X-ray
room is an unhealthy practice. Very often,
the x-ray technologists admit many patients
into the x-ray room before starting the
examination. Each time the technologist
exposes an x-ray film or the radiologist
screens a patient, the beam of x-rays directly
or indirectly strikes all those present.
Physicians should buy
only AERB approved
x-ray equipment. They
should comply with all
the radiological safety
requirements. . They
must use protective
accessories such as
gonadal shields, mobile
protective barriers, lead
aprons, etc, and motivate
workers to use these
accessories.
Patients may receive unnecessary radiation dose
during the waiting period. The dose may even
be greater than that received during their own
examination!
No one believes it. I had convinced the
editor of the Readers Digest to publish a
message on this practice in that magazine.
Patients must insist that they will not remain
in the x-ray room when others are examined.
We would like the public to ask those
who own and operate x-ray machines
whether their unit is an AERB approved one
or not. A “ type approved “ unit has all the
built-in safety features. X-ray manufacturers
and traders must sell only AERB approved
x-ray equipment.
The patient must tell her physician if she
is pregnant or thinks that she might be. This
must be done before a medical X-ray test is
carried out. The physician may cancel the
examination. He may postpone it or modify
it to reduce the radiation dose. He will
exercise better judgement and may proceed
with the test, as planned, only if it is essential.
At times, the risk of not carrying out a
clinically indicated x-ray examination might
very well be greater than the risk from
radiation.
In summary, x-ray equipment is a very
useful tool if it is used with care. Kerala
Government has set up an independent
Directorate of Radiation Safety to enforce
safety guidelines prescribed by the Atomic
Energy Regulatory Board. DRS will provide
radiation safety related advice and guidance
to those who approach the Directorate. ±
[Free booklet for
Physicians
A WHO booklet titled “ A
rational approach to radiodiagnostic
investigations” lucidly explains the
limitations of medical x-ray
procedures. Dr. K.S. Parthasarathy
secured its copyright and reprinted
a booklet titled “Patient Protection
in Diagnostic Radiology” published
by the International Commission on
Radiological Protection (ICRP). If
any physician wants a free copy of
the booklet, he may write to
Secretary, Atomic Energy
Regulatory Board, Niyamak
Bhavan, Mumbai 400094.]
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