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S.I. No. 250/1998:
EUROPEAN
COMMUNITY (RADIOLOGICAL AND NUCLEAR MEDICINE INSTALLATIONS) REGULATIONS,
1998
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EUROPEAN COMMUNITY (RADIOLOGICAL AND NUCLEAR MEDICINE INSTALLATIONS)
REGULATIONS, 1998
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The Minister for Health and Children in exercise of the powers conferred
on him by Section 3 of the European Communities Act, 1972 (No. 27 of 1972),
hereby makes the following regulations for the purpose of giving effect to
Article 3 of Council Directive 84/466/ Euratom(1) laying down basic measures for
the radiation protection of persons undergoing medical examination or treatment.
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(1)Official Journal of the European Communities, No. L265, 5/10/84 (Pages 1-3)
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1. These regulations may be cited as the European Communities
(Radiological and Nuclear Medicine Installations) Regulations, 1998.
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2. In these Regulations :
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"Medical Council" means the Council established by the Medical
Practitioners Act, 1978 (No. 4 of 1978);
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"Dental Council" means the Council established by the Dentists
Act, 1985 (No. 9 of 1985);
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"Radiological Protection Institute of Ireland"
means the Institute established by the Radiological Protection Act, 1991
(No. 9 of 1991);
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"the Minister" means the Minister for Health and Children;
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"medical practitioner" means a registered medical practitioner
as defined in the Medical Practitioners Act, 1978 ;
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"dental practitioner" means a registered dentist as defined in
the Dentists Act, 1985 ;
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3. In these Regulations words and phrases shall, except where otherwise
indicated, be construed as a reference to an article contained in these
Regulations or, as may be, to the schedule thereto; any reference in an
article to a sub-article shall be construed as a reference to a sub-article
of that article.
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4. These Regulations shall apply to radiological and nuclear medicine
equipment, apparatus and installations.
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5. The provisions of these regulations shall be without prejudice to the
rights and responsibilities of the Medical Council or the Dental Council in
relation to the competence of the medical practitioner or dental
practitioner concerned to use ionising radiation in the course of his or her
work.
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6. The provisions of these regulations shall be without prejudice to the
rights and responsibilities of the Radiological Protection Institute of
Ireland in relation to the custody, transportation, handling, holding,
storage, use, manufacture, production, processing, importation,
distribution, exportation, or other disposal of radioactive devices, nuclear
devices or irradiating apparatus.
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7. Radiological and nuclear medicine equipment, apparatus and
installations being used for diagnostic or therapeutic purposes including
general radiography, fluoroscopy, computerised tomography, mammography,
dental radiography, nuclear medicine and radiotherapy shall comply with the
criteria listed in the Schedule to these Regulations.
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8. The competent authority in the state for the purpose of Article 3 of
Council Directive 84/466/Euratom shall be the Minister for Health and
Children.
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SCHEDULE
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1. RADIOTHERAPHY
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TREATMENT ROOMS
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(i) Dose Control
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Treatment Rooms (excluding wards where manually controlled sealed source treatment are carried out) shall be designed and shielded
so that, from a consideration of work practices, use and occupancy factors,
the following doses would not be exceeded. (For rooms used to house
equipment operating above 10 MeV the neutron
generated contribution to dose shall be included).
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Category of Personnel
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Design Level (millisieverts/year)
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Exposed workers
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5
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Other workers employed in the hospital or clinic
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.5
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* In patients (per admission but exlcluding
radiation doses associated with their medical care)
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.5
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Visitors temporarily occupying locations adjacent to treatment rooms
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.5
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All others
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.05
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* Shielding requirements for in patient wards should take account of such
factors as typical length of hospital stay and the number of times the same
patient might be admitted per year.
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(TO BE READ IN CONJUNCTION WITH S.I. No. 43 of 1991 )
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(ii) Barriers & Interlocks
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The entrance to the treatment room shall be fitted with a door or other
barrier with an interlock which switches off the radiation source if entry
is attempted. It shall not be possible to restart treatment other than from
the control console.
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(iii) Warning Signals & Notices
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The entrance shall be fitted with one light which illuminates when
the equipment is in a state of readiness to emit radiation and another which
remains illuminated for the duration of the exposure.
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These warning lights shall be accompanied by a notice which warns against
entry when the warning light is on. The lights should also be wired, so that
if a warning bulb fails, the equipment will not operate.
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When treatment is taking place a visible warning signal is required
within the treatment room. In the case of external beam treatment this shall
be augmented by a continuous audible warning (in the case of x-ray unit and
linear accelerators the noise produced by the equipment will normally
suffice). In the case of isotope sources the in-room warning systems shall
be energised by a gamma ray detector.
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(iv) Emergency Equipment
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A rod or other device to return a stuck source shall be located in a treatment
room which houses external beam radioisotope equipment.
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2. Construction of Sealed Sources
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(i) Source Encapsulation
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Sealed sources shall meet the following ISO 2919 source classification
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Temperature
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Pressure
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Impact
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Vibration
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Puncture
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Brachytherapy
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5
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3
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2
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1
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1
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External Beam
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5
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3
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5
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2
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4
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A sealed source shall be deemed to be leaking if the removable activity
exceeds 185 becquerels.
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(ii) Identification
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The serial number and radioactive contents of manually used sealed
sources shall be clearly visible or shall accompany source if size does not permitt affixing to source. All sources shall be
accompanied by certificates of leak tests, radioactive contents and activity
reference dates.
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(iii) Security
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All equipment which incorporates sealed sources shall be designed such
that a power failure will cause the source to return to the "safe"
position. In the case of remote afterloading
devices provision shall be made for removal of the source to a safe location.
All equipment shall be fitted with a lockable device to prevent unauthorised
use.
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3. External Beam Equipment
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Leakage (beam "on")
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The leakage from the source housing shall be less than 0.1% of the useful
beam exposure rate at that distance.
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Leakage (beam "off")
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The maximum leakage exposure rate shall not exceed 100 Sv h-1 at 1 m and the average shall not
exceed 20 Sv h-1 at 1 m.
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Control Panel
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The control panel shall be fitted with—
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(i) a light which
indicates when the machine is in a state of readiness to emit radiation.
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(ii) a light which indicates when the machine is
"on" i.e. producing radiation.
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(iii) 1 a timer which automatically terminates the exposure after a
preset time and a. second timer which automatically terminates the exposure
if the first one fails to do so.( Cobalt Units)
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2 A two channel ionisation chamber with differential settings and an overide timer (Linear Accelerator)
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(iv) a switch to terminate the exposure at any
time.
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The control panel should be fitted with a device which indicates when
wedges and other beam compensators have been placed in the treatment beam
(this requirement is mandatory for all equipment installed after 1 January 1992).
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4. Mechanical Performance (external beam equipment)
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NB In this section the isocentre is
defined as the centre of the smallest sphere through which the axes of the
radiation beams pass in all conditions.
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(i) Accuracy of devices indicating the isocentre: 2 mm under all conditions.
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(ii) Accuracy of devices indicating the axis of the beam: 2 mm regardless
of any variation in either field size of SSD.
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(iii) Accuracy of devices indicating distance along the axis: 2 mm over
working range.
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(iv) Accuracy of numerical indication of x-ray field size ≥ 2 mm up to
20cmx20cm field size and ≥ 1% for larger field sizes.
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(v) At normal treatment distance (NTD)
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Distance between edge of light field and 50% x-ray contour for field
sizes 5 cm minimum dimension to the maximum available: 2 mm (this may
increase to 3 mm at 1.5 NTD).
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(vi) Distance between centre of radiation and light fields ≥ 2 mm at NTD and ≥ 3 mm at 1.5 NTD.
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(vii) Couch movements.
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(a) For a vertical movement of 20 cms, which
includes NDT, the horizontal movement shall be ≥ 2
mm.
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(b) Couch isocentre rotational movement.
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The couch isocentre shall pass within 2 mm of
the isocentre.
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(c) Couch rotational movement.
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Couch rotation axis shall be parallel to the couch isocentre
rotation axis to 0.5°.
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(d) Couch rigidity.
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The couch top at the isocentre should not
deflect vertically by more than 5 mm for a load increase of 30 kg to 135 kg
at full couch extension.
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(viii) Accuracy of scales
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(a) Angular scales should indicate angles correct to 0.5°.
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(b) Linear scales and readouts should read correct to 0.5 mms.
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5. Dosimetry
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In this section d80 is the depth in centimetres of the 80%
depth—dose value for a 10 cm x 10 cm field at the isocentric
distance from the machine.
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(i) Tolerance limits for x-rays
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(a) energy < 10 MV d80 = 8.5 cm
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allowable deviation in d80: 2 mm
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(b) energy > 10 MV d80 : 8.5 cm
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allowable deviation in d80 : 3 m(c) variation with gantry
angle and pulse rate frequency: 1 mm.
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(ii) Tolerance limits for electrons:
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a) deviation in d80: 2 mm for
energies up to 30 MeV (d80 = 9 cm).
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b) variation with gantry angle and pulse rate frequency: 1 mm.
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(iii) Field uniformity (photons)
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(i) Flatness limits are given in the following
table
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Field Size
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Value of x along
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Flatness
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Major Axis
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Diagonal
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50 - 100 mm
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10 mm
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25 mn
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1.06
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101- 300 mm
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0.1 x Field Size
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0.2 x Field Size
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1.06
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+ 5 mm
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301 - Max
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30 mm
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65 mm
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1.10
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Where x is the distance from the edge of the field and the flatness is
defined as Maximum dose within the beam
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Minimum dose within the flattened area
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(ii) Variation of flatness with gantry angle, prf:
1.5 % (provided that flatness limits in (i)
are not exceeded.
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(iii) Field Symmetry
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Greatest values of ratio of High Dose/Low Dose for each pair of points, each averaged over 10 mm profile line, within the
flattened area.
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Symmetry tolerance limits 1.03
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(iv) Field Uniformity (electrons)
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(a) Flatness specification
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(i) At the depth-dose maximum, the distance
between the 90% dose level and the geometrical beam edge is
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along major axes
= 10 mm
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along diagonals
= 20mm
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and the maximum dose at any point relative to
the actual axix is 1.03.
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(ii) At the depth of the 90% depth-dose value, the corresponding distance
between the 80% dose level and the geometrical beam edge is:
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along major axes
= 15 mm
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along diagonals
= 30 mm
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(b) Variation with gantry angle, p.r.f.
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Allowable variation = 1.5% provided that the above flatness limits are
not exceeded.
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(c) Symmetry
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Symmetry = Greatest Value of High Dose/Low dose for each pair of points
each averaged over 10 mm of profile within the region bounded by the 90%
dose values.
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Symmetry Tolerance Limit = 1.03.
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(v) X-ray contamination (electrons only)
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When measured 10 cm beyond the electron range, and expressed as a
percentage of the maximum electron beam dose on the central axis of the
beam, the x-ray Contamination shall not exceed the following values:
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898 Nominal Energy MeV
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% Allowable
Contamination
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4
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3.5
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6
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3.8
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8
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4.0
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10
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4.3
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15
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5.0
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20
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6.3
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25
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7.5
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30
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8.8
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Depth-dose fall-off
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Ratio of Practical Range
: 1.7 for all Nominal Energies 4-30 MeV
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d80
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Output
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(i) Linearity—at least 10 exposures involving
the same nominal dose shall be used to calculate the standard deviation in
the measured values.
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Limit .02 Gy or 2% which ever is the greater.
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(ii) Reproductability—the nominal dose selected
for the linearity test shall be divided into 5 equal portions. Measurements
should be made of the total dose for all, five portions given sequentially.
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The total reading shall be compared with the mean of the measured values
found in (i) above.
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Limit: .5 %
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(iii) Variation with gantry angle, prf:
difference between largest and smallest output < 3 %
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6. Dosimetry Equipment
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(i) Dosimetry
Calibration Equipment
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Dosimeters used for patient dosimetry shall
have a calibration which is traceable to a primary standard laboratory.
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(ii) Radiation Survey Equipment
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Dosimeters used for radiation surveys shall have a calibration which is
traceable to at least a secondary standard laboratory.
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2. GENERAL RADIOGRAPHY
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Warning lights/indicators
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A clear signal shall be given on the control panel indicating when the
x-ray tube is prepared to emit x-rays, and also when an exposure is taking
place.
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For permanently installed equipment there shall be a warning light at
each entrance door to indicate when the x-ray tube is primed to emit
radiation. This light shall be accompanied by a notice which indicates that
entry is prohibited when the light is on.
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Where two or more tubes are controlled from the same generator there
should be a clear indication which tube is selected to produce x-rays.
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Exposure Control
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The exposure switch shall be designed so that an exposure may only be
initiated by applying pressure to the switch and that the exposure may be
terminated by removing such pressure.
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For mobile systems the exposure switch shall allow the operator to stand
at least 3 metres (m) from both the tube and the patient.
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A key operated locking switch or equivalent should be provided for mobile
equipment to prevent use by unauthorised personnel.
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Focal spot
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a. Indication
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Every tube housing should have a mark indicating
the position of the focal spot position.
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b. Focal spot size
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While no absolute standard is specified, focal spot size determinations
should be carried out throughout the working life of a tube as part of the
quality control procedures.
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Leakage radiation
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The leakage radiation from the tube housing shall be less that 1 mGy and should be less than 0. 1 mGy
in one hour (air-kerma) at 1 m from the focal spot
at the maximum tube rating. The measurement shall be made over an area not
exceeding 100 cm2
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Filtration
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The inherent filtration of the tube assembly should be marked on the
housing.
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The total filtration of the x-ray beam shall be at least 2.5 mm Al of
which 1.5 mm shall be permanent. The added filters should be marked clearly
with the Al equivalent thickness.
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Kilovoltage
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The tube voltage setting shall be clearly indicated on the control panel
and shall be accurate to within:- 10% in the case
of single phase units and 5% in the case of three phase units.
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Mechanical Stability
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The x-ray tube shall be securely fitted and correctly aligned within the
tube housing. The tube housing shall be securely supported by mechanical
means.
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Capacitor Discharge Equipment
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Capacitor discharge equipment shall be equipped with a
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1. Means of preventing emission of radiation when the exposure switch is
not activated.
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2. Visual means of indicating the state of charge of the high potential
capacitor.
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3. Means of discharging the high potential capacitor to less than 30
volts without producing radiation.
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Radiation Output
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a. Indication
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The current and exposure time settings (or mAs
setting) should be clearly indicated on the control panel.
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b. Magnitude
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The radiation output measured at 1 metre from the focal spot should be in
the range: -
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25 - 75m Gy/mAs for single phase units
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40 - 115m Gy/mAs for three phase units
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with the voltage set at 80 kVp
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c. Consistency
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The radiation output shall be constant for repeated exposures within :-
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10% for single phase units
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5 % for three phase units
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d. Variation with change in selected current
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The variation shall be within:-
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15% for single phase units
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10% for three phase units
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e. Variation with selected mAs
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The variation shall be linear within:
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20% for single phase units 10% for three phase units
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f. Variation with selected kV
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The radiation output should vary according to the square of the selected
tube voltage.
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Timer Accuracy
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The actual exposure time shall be within 10% of the selected exposure
time.
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Field Size
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General purpose radiographic equipment shall be provided with an
adjustable collimator which provides adjustment of the field size and with a
light beam diaphragm.
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When the axis of the x-ray beam is perpendicular to the plain of the
image receptor, the centres of the x-ray field and the image receptor shall
be aligned to within 2% of the source - image receptor distance.
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The sum of the misalignment of any two opposite edges of the visually
defined field with the respective edges of the x-ray field shall not exceed
3% of the distance from the source to the centre of the visually defined
field, and the sum of the deviations in two perpendicular directions shall
not exceed 4%.
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3. FLUOROSCOPY
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In addition to the requirements for general radiography the following
additional requirements hold for fluoroscopy systems.
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Imaging devices
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Equipment for fluoroscopy shall be provided with the means of confining
the radiation beam to the image receptor area whatever the distance between
tube and receptor.
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Image intensifiers and TV systems shall be used as the image registration
systems in fluoroscopy.
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The housing of the image intensifier shall provide shielding equivalent
to at least 2 mm Pb for use up to 100 kVp, or 2.5 mm Pb for use up
to 150 kVp.
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Exposure switches
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Footswitches shall be designed to prevent inadvertent production of
x-rays. If resetting of the timer is automatic then a further exposure
should only be possible if pressure has been released completely from the
switch.
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In addition to the mechanical means of terminating screening via the
switches there shall be provision for automatic termination after a
predefined screening time not exceeding 10 minutes. The device shall give an
audible signal before termination to enable the operator to reset the system
if the exposure time needs to be extended.
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Fluoroscopy systems that utilise both hand and foot switches shall be
designed so that one or the other switch is operational at one time but not
both simultaneously.
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Operator protection
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Adequate protection for staff against scattered radiation shall be
provided on tables and stands used for fluoroscopy.
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Patient doses
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Dose-Area product meters should be fitted to fluoroscopy equipment in
hospitals which undertake radiological training.
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The skin entrance air-kerma rate shall not
exceed 100 mGy/min and
should not exceed 50 mGy/min at the shortest focal
spot to skin distance specified for the equipment.
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4. COMPUTERISED TOMOGRAPHY (CT)
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The following additional requirements hold for CT in addition to those
for general radiography.
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Shield size
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The radiation beam should have no cross sectional dimension greater than
that required to cover the active element of the radiation detector.
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Shielding
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The housing should provide shielding equivalent to at least 2.5 mm Pb.
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Automatic exposure termination
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The exposure should terminate as soon as the selected scan has been
completed or scanning stops. If scanning mode is selected an exposure should
not be possible if there is a failure of the scanning motor.
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Emergency Stop
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There shall be a simple mechanism to terminate an exposure in an
emergency.
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5. MAMMOGRAPHY
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Focal spot
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The position of the focal spot shall be clearly marked on the tube
housing.
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The focal spot should have dimensions ≤ 0.5 x 0.5 mm. If magnification is
to be performed then the focal spot should be ≤ 0.2 x 0.2 mm.
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Filtration
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The total filtration of the assembly should be ≥ 0.5 mm. Al or ≥ 0.03 mm Mo.
The total filtration should be clearly marked on the tube housing.
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For units equipped with changeable filters there shall be a clear
indication which filter is selected.
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The tube voltage should range between 25 and 35 kVp.
The kVp setting on the control panel should be
accurate to 1 kV and shall be within 2 kV of the dial setting.
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Mains compensation
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The mains electrical compensation should be automatic. The tube voltage
shall be maintained at a value of within 1 kV of the selected value /kV for
a mains voltage fluctuation of 7%
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The leakage radiation from the tube housing should be less than 0.25 mGy in one hour (air-kerma) at
one metre from the focal spot measured over an area not exceeding 100 cm2
at the maximum tube rating.
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Exposure control
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The exposure switch shall initiate an exposure when pressure is applied
and the exposure shall terminate if pressure is released.
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The system should be Fitted with automatic exposure control. This should
be reliable and consistent and maintain a variation of film density of less
than 0.1 density units for the range of tube voltages and breast thicknesses
of 2 to 6 cm. This may not be possible with some older equipment
(manufactured prior to 1988).
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The system should be fitted with a guard timer to terminate an exposure
after a predefined time if the automatic exposure control mechanism has not
functioned properly. The value of the predefined time should be documented
by the manufacturer.
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The manufacturer should clearly document whether the automatic exposure
control mechanism can compensate for film reciprocity law failure.
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The control panel shall clearly indicate when an exposure is taking
place. The system should be provided with a post-exposure readout of mAs.
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Focus to film distance
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The focus to film distance should fall in the range of 55 - 65 cm.
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Grids
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The system should be provided with a secondary radiation grid with a grid
exposure factor of less than three. The grid specifications (grid ratio line
density, stationary or bucky, etc.) should be
documented by the manufacturer.
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Compression plate
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A compression plate shall be provided on the system. The compression
force should be greater than 150 N and less than 200 N.
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Use of low attenuating materials
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The table top grid and cassettes shall be made from low attenuating
materials.
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Breast dose
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The entrance dose to the breast should not exceed 7 mGy.
The mean glandular dose per radiograph should not exceed 3 mGy and shall not exceed 5 mGy.
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Support table
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The support table shall act as a primary beam absorber. There shall be no
significant transmission of radiation through it.
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6. DENTAL X-RAY SYSTEMS
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Focal spot
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The position of the focal spot shall be marked on the tube housing.
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The focal spot size should be measured throughout the working life of the
tube to determine the extent of deterioration.
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Leakage radiation"
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The leakage radiation shall be less than 1 mGy
in one hour (air-kerma) measured at I metre from
the focal spot and over an area not exceeding 100 cm2 for the
maximum tube rating. For systems involving intra-oral films the leakage
radiation should not exceed 0.25 mGy in one hour
under the same measurement conditions.
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Kilovoltage
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The tube potential shall not be less than 50 kVp
and the kVp setting on the control panel should be
accurate to within 5
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Filtration
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The total filtration shall be at least 1. 5 mm Al for kVp
< 70 kV and at least 2.5 mm Al for kVp ≥ 70kV.
The inherent filtration should be marked on the tube housing and added
filters should be marked with their value in Al equivalence.
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Focus to skin distance
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For systems employing intra-oral films the field spacer cone shall ensure
a minimum focus to skin distance of:
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20 cm for kVp ≥ 60kV
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and 18 cm for kVp < 60kV
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Open ended cones should be used.
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The field width at the patient end of the cone should be less than 6 cms and shall be less than 7 7cms.
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Exposure control
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An exposure shall be initiated only by applying pressure to the exposure
switch. It shall also be possible to manually terminate an exposure by
releasing the pressure on the switch.
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When the mains voltage is switched on there should be a clear indication
of this on the control panel.
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The control panel shall be fitted with a light to indicate that an
exposure is in progress.
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Where preset exposure times are assigned in different dental
examinations, as in anatomical timer, the preset time should be clearly
documented by the manufacturer.
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The preset exposure times shall be within 10% of those specified by the
manufacturer. The same holds for manually selected exposure times.
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Operator-protection
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The cable length shall be sufficient to allow the operator stand at least
2 m from the x-ray tube and patient.
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Radiation Output Consistency
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For repeat exposures, the output shall be constant to within
; 10%.
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Panoramic Units
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Panoramic units should be fitted with a device to limit the minimum focus
to skin distance to 15 cm.
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On panoramic units the primary beam shall be collimated such that the
size of the useful beam at the image receptor does not exceed by more than
2% of the source to image receptor distance, each dimension of the scanning
slit.
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Film storage and processing (all applications)
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Storage and processing facilities shall be designed and located so that
films are not exposed to more than 2 Gy prior to
development.
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7. NUCLEAR MEDICINE INSTALLATIONS
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Gamma camera performance parameters to be tested and documented
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Integral and differential uniformity.
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Integral resolution.
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The system resolution at the collimator surface and at 10 cm depth in
tissue equivalent material for each collimator.
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The sensitivity of the system with each collimator over the range of
energies for which that collimator is to be used.
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Design and Performance standards
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The gamma camera should have a mechanism for selecting `energy windows'
appropriate to the range of radionuclides used in
the installation. It should clearly indicate which energy window is
operational and should have a simple system for verifying the accuracy of
the window position.
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The gamma camera should have a mechanism for terminating a study
manually, by predefined counts and by predefined time. For systems that
perform whole-body scanning or tomography there shall be an emergency stop
mechanism.
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The integral uniformity shall be 10%.
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Shielding
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The installation shall have a facility for preparing radiopharmaceutical
injections with adequate protection for the operator and patient.
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Syringe shields shall be available in the installation. If
radiopharmaceutical injections have to be transported "within the
installation then shielded transport boxes shall be available also.
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Calibration
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An Activity Calibrator/Dose Calibrator shall be used to quantify
radioactive content of radiopharmaceutical injections. The Calibrator should
be accurate to within 15% and should be linear with variation in activity.
The calibrator shall be calibrated at least every year.
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Radiological Hygiene
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Washing facilities and appropriate decontamination equipment shall be
provided in the installation.
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Calibrated contamination monitoring equipment shall be available in the
installation.
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The installation should have a designated waiting area segregated from
that used for other imaging modalities.
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Radioactive waste
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Suitable shielded storage facilities for waste material shall be
available in the installation to enable compliance with local waste disposal
requirements.
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Given under the Official Seal of the Minister for Health and Children
this 21st day of July 1998
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Brian Cowen T.D.
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MINISTER FOR HEALTH AND CHILDREN
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EXPLANATORY NOTE
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These regulations establish the criteria of acceptability to be met for
radiological installations and nuclear medicine installations. The
Regulations implement the provisions of EC Directive 84/466 Euratom of 3 September of 1984 laying down the basic
measures for radiation protection of persons undergoing medical examination
or treatment and to provide protection for workers and the general public.
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