Radiation Protection aka Dose Reduction Mechanisms Flashcards
Goals for Oral and Maxillofacial
Radiology
(2)
- Reduce radiation exposure
- Maintain a high degree of diagnostic
efficiency
It’s a juggling act to:
(2)
●reduce a patient’s radiation exposure
●maintain a high degree of diagnostic efficiency
Dose Reduction Mechanisms
(4)
X-ray Tube Head
Patient Protection
Operator Safety
Et cetera
Guiding Principle of
Radiation Protection
Since the probability or severity of biological
damage increases as the radiation dose
increases, it is desirable to
avoid receiving even
the smallest dose of radiation unnecessarily.
ALADA lowers exposure
(2)
to patients
of all office personnel
Dose Reduction Mechanisms
X-ray Tube Head (Mandated)
(2)
- Filtration
- Collimation
Filtration
(3)
- Selective passage of contents through a
specified substance - Selectively removes a greater proportion of
low keV x-ray photons - Increases mean energy of the beam
Mandated Minimum Total Filtration
for X-ray Tubes
Operating kV: Aluminum Filtration (mm)
<50:
50 to 70:
>70:
0.5mm
1.5mm
2.5mm
EXIT SIDE
BEAM COLLIMATION
(2)
- Maximum 2.75” diameter
- (Rectangular preferred)
Dose Reduction Mechanisms
X-ray Tube Head Options
(4)
- Rectangular
collimator - High kV generator/
transformer - Constant potential
(DC) fully rectified - Increased focal length
effective dose is reflective
of the
specific technique
Increased of Long BID Benefits
(3)
- 27% less head volume
- reduced effective dose
- sharper image
Dose Reduction Mechanisms
Practice Options
(4)
- Film speed
- Lead (Pb) thyroid collar
- Film-holding devices with beam alignment
capability - Time-temperature quality control processing
FILM SPEED
(4)
- “D” speed (Ultraspeed)
- “E” speed (Ektaspeed)
- “F” speed (Insight)
- digital receptors
- digital receptors
(3)
- Photostimulable phosphor plate (PSPP)
- Charge Coupled Device (CCD)
- Complimentary Metal Oxide Semiconductors (CMOS)
PATIENT PROTECTION
(2)
- Lead apron
- Thyroid collar
Operating Policy Regarding the Use of
Diagnostic Ionizing Radiation
(2)
- During an exposure taken with a wall-mounted x-
ray unit, the operator shall stand behind a
protective barrier. - If a barrier is not present, the operator shall stand
at least six feet from the patient and at an angle
between 90° - 135° to the direction of the useful
beam.
NEVER
Stand in the …
primary beam
POSITION AND DISTANCE
Stand at least
(2)
- 6 feet away and,
- 900 –1350 to the
primary beam
NEVER
Hold film or other receptors …
in a patient’s mouth
Radiation monitoring devices are optional,
but…………….
* — will be worn by all full-time
operators of radiographic equipment while x-
ray exposures are being made.
* Annual occupational whole body exposure will
not exceed – mSv
* Operators who have declared a pregnancy will
not receive more than – mSv to the embryo
or fetus during the term of the pregnancy.
Dosimeter badges
50
5
The NOMAD and NOMAD Pro are
self-contained, hand-held, portable
dental X-ray units.
OMAD Use Violates current
radiology statutes
(2)
- “During each exposure, the operator
shall stand at least 6 feet from the
patient or behind a protective barrier.” - “Neither the tube housing nor the
position indicating device (cone, cylinder)
shall be hand-held during exposure.”
Exemption for licensed hand
held units
* A — (provided by the
manufacturer) must be permanently mounted to
the cone and used at all times during
radiographic exposure.
* Operators must wear a — that is evaluated monthly.
* All personnel must receive —
backscatter shield
personnel monitor
device
training in the safe
use of these X-ray systems, and records of the
training kept for review.
Maximize the operator’s area of protection by doing the following:
(3)
- Place the backscatter shield at the end of the PID (closest to the patient).
- Align the PID close to the patient.
- Keep all body parts within the area of the shield’s protection.
