Blue Book - Radiation Shielding for Medical Instalations

The "Blue Book" PET
Recommendations and Methods
Professor Jim Malone
Robert Boyle Professor of Medical Physics
Trinity College/St James’s Hospital, Dublin
IAEA, RPoP Unit, Vienna

What is Different
• Photon Energy (511
keV)
• Relatively High Activity
• Relatively Short Half Life
( 18 F, 109.8 min, many shorter)
• Production, distribution
and labelling
• Metabolism of the
radiopharmaceuticals
• Patient flow and
management
Imaging equipment
Based on AAPM 108 AND Simkin et al.

Areas Required
• Patient Interview area
• Patient waiting area
• Uptake/injection areas
• Patient WC
• PET scanner room
• Control room/area
• Dispensing area
• Waste storage area
• Patient Interview area
• Very important to
reducing staff dose and
amount of shielding
• Patient fully briefed on
what will happen and
questions answered
fully before bf injection

Some Principles and Siting
Relationships
• Close affinity with Nuclear Medicine
• If no restrictions on access, constraint is 0.3
• Protect staff and public
• Protect scanner from patient interference
• Patients enter and leave without entering
“staff only” areas
• Protect scanners/counting equipment in
neighbouring departments from patient
entering or leaving

A Layout for a PET Facility
Grouping patient areas reduces amount of shielding needed and staff dose

The Scanning
Area

The Scanning Area (Photo)
• Typically 30 – 50 m 2 , size
matters
• With newer systems, need
for server area may not
arise
• Console are accessible to
general hospital staff
“attracts” constraint 03 0.3,
i.e. design challenge
• PET/CT shielding and
injector issues

Uptake Areas

Uptake Areas (Photo)
• Number required
depends the workload
• Usually 3 to 6
• Shielding required
• CCTV will reduce staff
dose
• Use of concrete nibs
• Dedicated toilet
reduces patient traffic
and need for shielding
elsewhere

Dispensing and Waste
• Similar to Nuclear Medicine
• Higher energy, will mean heavier shielding
• Delivery arrangements likely to be more
frequent
• Less radiopharmaceutical handling
• Waste management will require segregated
storage and different levels of shielding. Well
managed, apart from short term, it can be
shared with nuclear medicine

PET Radiopharmacy

Shielding Calculations
• Data for 18 F:
– Activity given: 555 MBq
– Dose Rate Const: 0.148µSvm 2 /MBqh for point
– Becomes: 0.092µSvm 2 /MBqh for patient
– Assume 1h uptake tk period
– Assume 50 patients/week, 52 week year, and 4 m
to point of interest in area of 10occupancy 1.0 occupancy, with
non radiation workers.
• Dose Constraint: 03mSv 0.3

Shielding
Calculation
(PET Scanning
Room)

Shielding
Calculation
(PET Uptake Room)

Shielding Data
(from AAPM, 2006)
mm Pb; or
cm Concrete
Transmission
1.0 0.89 0.96
5.0 0.52 0.72
10 0.25 0.40
50 0.0005 0.0009

Conclusions
• High Energy and High Activity
• Balance size, distance and shielding
• Separate staff and patients as far as is
consistent with good care
• Shielding calcualtions are individual for now,
and more documented experience needed