December 27, 2012
Radiation alert on hand-held dental
X-ray unit
K.S. PARTHASARATHY
TOPICS
Purchasing
articles from e-Bay or other similar websites is cool! However, occasionally,
it can become dangerous and troublesome. Recently the UK Medicines &
Healthcare products Regulatory Agency (MHRA) found that a hazardous hand-held
dental X-ray machine is on offer at e-Bay. Tianjie Dental ‘Falcon’ hand- held
X-ray set is made in China and has very serious deficiencies.
INADEQUATE SHIELDING
It does
not have adequate shielding in the X-ray tube. As its design is primitive, the
device has substantial, non-acceptable leakage radiation.
MHRA
has asked the National Health Service (NHS) and private dentists to dispose of
these devices, if they have purchased them
At
around 200 pounds, one can purchase the unit on auction. Safe, hand-held dental
X-ray units are available; however they cost more, around 4,000 pounds each.
HPA
found that under realistic work-load, operators of these unsafe units may be
exposed to doses in excess of the annual limits prescribed by the regulatory
body. The operators may get localised skin damage as the radiation levels at
the locations where they hold the unit are very high.
Such
units will expose patients to significant leakage radiation, resulting in doses
almost ten times greater than it would be if the X-ray tube was adequately
shielded and the X-ray beam was collimated to just the primary X-ray beam.
FIRE, SHOCK HAZARD
HPA
found that the device comes with a European plug and a travel adapter that are
not earthed or fused for the U.K. mains supply. Besides being a fire hazard, it
could cause a fatal electric shock (50,000 volts) to the dentists or patients.
“Exact numbers in use in dental surgeries in the UK are unknown, but at the
present time we are aware of two dentists who bought the article.
“The UK
regulator for medical devices (the Medicines and Healthcare Products Regulatory
Agency, MHRA) seized 13 more units from an importer based in the West Midlands
before they could be sold” Mr Andrew Gulson, DXPS Technical Manager &
Radiation Protection Adviser, Centre for Radiation, Chemical and Environmental
Hazards, Health Protection Agency responded to an e-mail query.
HPA
first became aware of this particular model of hand-held device following an
enquiry from MHRA.
“As HPA
was already investigating the safety of hand held dental X-ray sets we decided
to buy one ourselves from the eBay website to test as part of this project,” Mr
Gulson added.
“Medical
devices such as diagnostic X-ray sets used in the EU should be CE-marked to
show they have been assessed to comply with the relevant EC Directives.
In the U.K., it is the responsibility of the dentist to ensure X-ray equipment
that they purchase meets this requirement; no further licensing or
authorisation is required prior to purchase.
The
case of the Tianjie Dental Falcon, which can be purchased online from a
supplier based outside the EU, demonstrates that dentists who may be unaware of
their responsibilities to use CE-marked equipment can nevertheless obtain it
very easily and at low cost.
I
understand that MHRA is working with Internet-based sellers to remove this
model from their websites, but at the present time this and similar models
continue to be available for purchase online in the U.K. and around the world”
Mr Gulson clarified.
“Dentists
who are unaware of their legal obligations are therefore most at risk of
obtaining and using a device such as the Tianjie Dental Falcon with no
recognition of the radiation hazard to themselves, their staff or patients,” he
asserted. The full test report which Mr Gulson sent to this writer highlights
the deficiencies.
THE REQUIREMENTS
As per
the requirements specified by the Atomic Energy Regulatory Board, radiation
generating equipment such as dental X-ray units used in India shall have “type
approval” from AERB. A type approved equipment will have the prescribed
built-in safety features.
Use of
radiation generating equipment not approved by AERB is a violation of the legal
provisions and will attract action under the appropriate provisions of the
Atomic Energy Act 1962 and the relevant rules.
With
the unbridled availability of such equipment, the story of X-ray comes to full
circle! X-ray units in use during the first few years of the discovery of
X-rays were similar.
K.S.
PARTHASARATHY
Former Secretary, Atomic Energy Regulatory Board
(ksparth@yahoo.co.uk)
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