Transcript Slide 1

Radiation Safety Refresher
Training for PET Imaging
For Record of Attendance
E-mail or Interoffice Mail Test to:
[email protected]
Stephen David, EH&S, CYF G.102
Radiation Safety Program
Environmental Health & Safety
713-500-5840
PET & PET/CT Imaging
• In PET imaging, the
system detects the
annihilation photons
(511 keV) from the
positron-emitting
radionuclide
introduced into the
body.
PET Imaging &
Radiation Sources
• The primary
radiation source
does not come from
the camera but from
the patient itself.
PET & PET/CT
Imaging & Radiation Sources
• Close patient-staff
interaction during and
following administration
of patient dose may
contribute to higher
occupational dose.
Radiation Area Monitoring
• Stationary area monitoring
has been in place at the PET
Center to assess potential
radiation exposures from
both PET and PET/CT
imaging just outside the
imaging suite.
PET
SUITE
Area Monitor Example
2012
Dose
1/1/12 –
3/31/12
5 mrem
2011
1/1/11 –
3/31/11
4/1/11 6/30/11
7/1/11 –
9/30/11
10/1/11 –
12/31/11
2011 Total
Dose
6 mrem
1 mrem
7 mrem
3 mrem
17 mrem
Area Monitor = ENV Series, PET Suite 04801
Dose Should be Less Than 100 mrem per Year
Contamination Monitoring
• Wipe Tests
• Performed routinely to assess removable
contamination.
• GM Detector Survey
• Used for fixed and removable
contamination assessments.
Routine Contamination
Monitoring
• Routine contamination surveys are performed
by both PET staff users and Radiation Safety
Program Staff of EH&S in accordance with
Texas Radioactive Material License L02774.
ALARA Review
Keep Occupational Exposures
As Low As Reasonably Achievable
• Minimize time near radiation
• Maximize distance
• Use appropriate shielding
while maintaining patient care!
ALARA Investigation Level
• UTHSC-H levels to initiate ALARA investigation
to ensure doses as low as reasonably achievable
(ALARA), doses in mrem.
Deep Dose
(DDE)
125 per
month
Eye Dose Shallow Dose
(LDE)
(SDE)
375 per
1,250 per
month
month
Occupational Considerations
in PET Imaging
• External Exposures from ex. F-18 FDG
• Majority from patient, typically
• Unsealed sources (should be periodically
monitored for potential spills)
• PET cameras often combined with CT
• Internal Exposures/Contamination
• Unsealed radiopharmaceuticals (i.e. spills,
digestion, needle prick)
Personnel Monitoring Examples
Date
Dose
Equivalent
PET
Operators
February 2012* (2/01/12 - 2/29/12)
May 2012 (5/01/12 - 5/31/12)
DEEP
EYE
SHALLOW
RING
DEEP
EYE
SHALLOW
RING
42 mrem
43 mrem
44 mrem
890 mrem
18 mrem
34 mrem
47 mrem
140 mrem
36 mrem
37 mrem
38 mrem
1790 mrem
12 mrem
20 mrem
26 mrem
280 mrem
8 mrem
8 mrem
9 mrem
60 mrem
2 mrem
1 mrem
1 mrem
--
13 mrem
13 mrem
13 mrem
30 mrem
<1 mrem
<1 mrem
<1 mrem
--
Physicians
*Note: Using N-13 due to lack of CardioGen-82 Generator
Personnel Monitoring Examples
Date
Dose
Equivalent
PET
Operators
December 2011* (12/01/11 - 12/31/11)
January 2012* (1/01/12 - 1/31/12)
DEEP
EYE
SHALLOW
RING
DEEP
EYE
SHALLOW
RING
25 mrem
25 mrem
26 mrem
1260
mrem
25 mrem
25 mrem
25 mrem
560 mrem
18 mrem
18 mrem
18 mrem
760 mrem
37 mrem
53 mrem
63 mrem
2010
mrem
3 mrem
3 mrem
3 mrem
< 1 mrem
5 mrem
5 mrem
5 mrem
40 mrem
6 mrem
6 mrem
6 mrem
<1 mrem
8 mrem
9 mrem
9 mrem
< 1 mrem
Physicians
*Note: Using N-13 due to lack of CardioGen-82 Generator
PET Shielding
• Syringe Shielding
• very effective at reducing
exposure to hand
511 keV Gamma energy
needs thicker shielding
than other common
nuclear medicine
procedures
PET Shielding
• Syringe Shielding
• A syringe shield made of
tungsten with a thickness
of 0.34” (9mm) attenuates
FDG-18 by 88%.
Radioactive Spill Procedures
• PET uses unsealed radioactive
sources.
• Spills may occur and contaminate:
imaging cameras, beds, tables,
bathrooms, technologists, etc.
• Specific procedures & protocols are in
the UTHSC-H Radiation Safety Manual
and PET Suite Operating Procedures.
Radioactive Spill Supplies
• Obtain necessary supplies
for cleanup
• Paper towels or diapers
• RADCON or Scrubbing
Bubbles (DOW)
• Opaque plastic bags for waste
• Labels
• Gloves
• Descriptive forms for
documentation if needed
• If very short-lived, may restrict
area for decay to background
levels (ex. overnight for F-18 spill)
Records of Patients’ Log
Information on each patient’s
administration of a dose should all be
logged according to procedures.
• Example:
• Radionuclide
• Activity at Date & Time
• Compound
• Unique Number
Declared Pregnancy Program
for Employees
• The Program will assist the pregnant,
occupationally exposed employee in assessing
the potential radiation risk to the unborn child
during the course of employment.
•We can also help with methods of minimizing
the radiation dose and the risk to the unborn child
and maintaining the radiation doses as low as
reasonably achievable.
Declared Pregnancy Program
for Employees
Declared Pregnancy Program
Discuss current radiation levels with Radiation Safety.
Discuss techniques and options to minimize dose to mother and baby.
Declare in writing with Radiation Safety for reduced limit.
Reduced limits
Exposure should not exceed 0.05 rem/month.
Exposure shall not exceed 0.5 rem/gestation period.
Up to individual to declare
If she decides to declare, consult with Radiation Safety and implement
procedures.
In rare cases, declaration may change job duties.
To discuss with Radiation Safety, Call 713-500-5840
Pregnancy Check for Patients in
PET imaging
• Female patients ages 12-55 will
be screened for pregnancy prior
to diagnostic procedure.
•If patient unable to confirm nonpregnancy, urine test will be
performed prior to procedure.
•Screening is done to avoid
unintended dose to the fetus.
Pregnancy Check for Patients in
PET imaging
If diagnostic information received
outweighs risks, test will be performed
with written consent of patient.
The UTHSC-H Radiation Safety Manual
Addendum contains requirements for
human use of radioactive material with
regards to pregnancy checks for patients.
Unintended Dose to the Fetus
•Report immediately upon discovery to the
Radiation Safety Officer for notification to State
of a dose to an embryo/fetus if :
•Any dose to an embryo/fetus that is greater
than 5 rem (50 mSv) dose equivalent that is a
result of an administration to a pregnant
individual, unless the dose to the embryo/fetus
was specifically approved, in advance, by the
authorized user.
•From 25 TAC §289.256(vvv)
Unintended Dose to the Nursing Child
•Report immediately upon discovery to the
Radiation Safety Officer for notification to State of
a dose to a nursing child if :
•The dose is greater than 5 rem (50 mSv) dose
equivalent that is a result of an administration to a
breast feeding individual.
•Or has resulted in unintended permanent
functional damage to an organ or a physiological
system, as determined by a physician.
•From 25 TAC §289.256(vvv)
Medical Event
(Misadministration is a Medical Event)
• For all medical uses of licensed radioactive
materials, a “Medical Event” occurs if BOTH of
the following criteria are met :
(1) The difference between the dose administered
and the prescribed dose exceeds one of the
reporting limits the annual occupational dose
limits at 25 TAC §289.202 or 10 CFR
§20.1201, (ex. 5 rem effective dose equivalent)
Unintended Dose to the Fetus
Medical Event
When to contact RSO to call state
AND
(2) One or more of the following
representative incidents occur:
•
the dose administered to a patient differs from
the prescribed dose by at least 20%
•
the wrong radioactive drug is administered
•
the radioactive drug is administrated by the
wrong route
•
the dose is administered to the wrong individual
Unintended
Dose to the
Fetus
Survey Instruments
in PET
When to contact RSO to call state
Geiger-Meuller (GM) Counter
• Ideal for assessing
removable
contamination of
typical PET
radionuclides
Unintended
Dose to the
Fetus
Survey Instruments
in PET
When to contact
RSO
to
call
state
Ionization Chambers
• Ideal for assessing exposure
levels from radiation sources
Survey Instruments in PET
Well counter
• It is a small scintillation
counter
• To determine very small
activity in dpm
(disintegration per minute)
• For wipe test and leak tests
• Counts one sample at the
time
Unintended
Dose to the
Fetus
Survey Instruments
in PET
WhenDose
to contact
RSO
to
call
state
Calibrator (ionization chamber
measuring dose to the patients)
It is used to assay the
amount of radioactivity in
the test tube, vial, or
syringe.
It has to be calibrated for
all specific radionuclide
used by the department.
E.g. Rb-82, F-18, N-13,
O-15, C-11, I-124, Cu-62…
Unintended
Dose to the Material
Fetus
Receipt of Radioactive
Requirements
When to contact RSO to call state
•
DOT/FAA receipt training needed every 3 years,
specific to what individual receives.
•
Cannot exceed limits of the license.
•
Receipt procedures for PET Personnel for
shipments delivered directly to center
•
Wipe test upon arrival & record results in dpm.
•
Record surface readings in mrem/hr if Yellow II
•
Record activity received and date
Complete 5 Question Test
For Record of Attendance
E-mail or Interoffice Mail Test to:
[email protected]
Stephen David, EH&S, CYF G.102
Questions: 713-500-5840
Radiation Safety Program of EH&S