Overview of Shielding Required for aOverview of Shielding Required for a Typical Nuclear Medicine Dept.

Professor Jim MaloneRobert Boyle Professor of Medical PhysicsRobert Boyle Professor of Medical Physics

Trinity College/St James’s Hospital, Dublin

IAEA, RPoP Unit, Vienna

Some DifferencesSome Differences• Distribution of Radionuclide is imaged

• Framework varies regionally• Photon energy much higher• Activities from trivial to high

• Shield as close as possible to the source• Waste management• Other requirements, eg. Infection Control

Common Activities AdministeredCommon Activities Administered

• Bone Scan 500 - 600 MBq

• Renal Scan 100 MBq

L S (P f) 100 MB• Lung Scan (Perf) 100 MBq

Patient is an unsealed mobile leaky sourcePatient is an unsealed , mobile leaky source

Scope• Diagnostic (Primarily)• ImagingScope • Imaging• PET/CTH L b

O i f

• Hot Lab

Overview of Shielding Issues for a 

• In vivo measurements, including those in OR

Nuclear Medicine Department

• In vitro measurements• Laboratories

Department

• Therapy outside RT pydepartments

Order of PresentationOrder of Presentation

• Design PrinciplesDesign Principles

• Location and Access

i• Department Design

• Room Design

• Shielding SpecificsShielding Specifics

• Shielding Examples

Design PrinciplesDesign Principles

• Distance, where possible. Large rooms.Distance, where possible.  Large rooms.• Separate patients/staff (distance and time)

• Reduce time patients expose others

• Use shielding when distance and time isn’t ffi i tsufficient

• Shield as close as possible to the source

Location and AccessLocation and Access

• Remote from main hospital busy areas; p y ;Many functions selfcontained

• Connected with Imaging Areas

• Good access for deliveries, and patients leavingpatients leaving

• Ideally on a corner with nothing above or below, but ‐‐‐‐‐

Location and AccessLocation and Access

• Public access toPublic access to surrounding area or corridors implies 0.3 constraint

• Most hospital doctors and nurses are “public”, i.e not rad workers, and can commonly attend incan commonly attend in scanning or reporting roomsrooms

Pseudopod BuildingPseudopod Building

Facilities to be IncludedFacilities to be Included

• Separate patients and  • Radio pharmacy/Hot p pStaff

• Imaging Rooms• Patient Reception

p ylab

• Radionuclide Storage• Waste storage and• Patient Reception, 

Waiting• Waste storage and Handling

• Patient Injection• Cardiac Stressing• Patient WC

j

Possible Departmental LayoutPossible Departmental Layout

Avoid interfernce of one activity with another (eg.: injection room and camera room)

Possible Gamma Camera Room LayoutPossible Gamma Camera Room Layout

• Console• Console• Collimator Storage• Big room of 

30 – 40 m2

• Good orientation

• Dose constraints outside/windows

• Shielding to protect second camera room

• CT requires extra shielding

Gamma Camera Room (Photo)Gamma Camera Room (Photo)

Ventilation if  aerosols  and/or gasses 

(Xenon Strasse)

Possible Hot Room LayoutPossible Hot Room Layout

• Labelling may be g yon site or remotely

• Use of Hatches ( h ?)(why?)

• Lobby/change area

• All areas not always requiredrequired

Injection Room (Photo)Injection Room (Photo)

• Adjacent to radiopharmacy

• Hatch connection

• Two bays

• Shielding probably• Shielding probably required (why)

• Air extraction if ventilation patients

Hot LabHot Lab

• Strict access control

• Much shielding required.

• Use of concrete in benchs 

• Load bearing

2• About 20 m2 for 2 isolators/cabinets

• Storage and waste separate

• Area to facilitate delivery

Hot LabHot Lab

• Typically shielding requiredTypically shielding required

• Restrict access

• Accompanying staff should b bl ibe able to sit at a remove

• Separate toilet for injected• Separate toilet for injected patients (always contaminated)

• Toilet for accompanying persons

Other Facilities that influence structural shielding

Other FacilitiesOther Facilities• Waste, Storage etc.

• QA and minimal Lab.

• Clean Storage (~10 m2), segregation by activity levelsegregation by activity level

• OR Theatre

• Therapy  (isolation room for GBq amounts)

• Uptake assessment, 

• In vitro counting,

• Path labs Volatile materials• Path labs, Volatile materials

Shielding, GeneralShielding, General

• Not Point Source• Shielding as close as• Decay from dispensing to Administration

Shielding as close as possible to source

• Shielding for Generator • Decay from Administration to end of scan

g

• Shielding for vials

• Shielding for syringes of scanShielding for syringes

Shielding Calculations

Reception area adjacent to Gamma 

Camera RoomCamera Room

Shielding Attenuation of LeadShielding Attenuation of Lead

• Table D1Table D1

Dose Rate at 1m fromDose Rate at 1m from

• Table D2Table D2

All can reduce Structural Shielding

Designed for safely storing radioactive materials

All can reduce Structural Shielding

Designed for safely storing radioactive materials.

Larger generator drawer

Lead lined fridge

will accommodate the Mallinckrodt Generator with Elution Shield.

Big Differences and ConclusionsBig Differences and Conclusions

• Activity distributed but as far as possibleActivity distributed but as far as possible shield locally

• Many sources with many different other i ( h i ll fi frequirements (eg.: chemically, fire safety, 

infection control, manufacturing process)

• Working to 0.3, some shielding will be g , gneeded, depending on pattern of practice.