RCUF RCUF –– 22ndnd MeetingMeeting

NPL NPL -- Radioactivity Standards:Radioactivity Standards:

Progress on current NMS projects Progress on current NMS projects supporting the actions from the 1supporting the actions from the 1stst

RCUF meeting RCUF meeting

Presented by: Presented by: Michaela BakerMichaela Baker

Actions agreed at the 1Actions agreed at the 1stst RCUF MeetingRCUF Meeting

1. Future UK radionuclide calibrator comparison exercise

2. Co-sharing calibration exercise

3. Advertise future comparison exercises in RAD

4. Investigate the performance of dedicated Beta ion chambers

5. Calibration of 10R Type 1+ Schott vials

6. Copper insert for measurements of 123I - Repeat 123I comparison

7. Suppliers of radionuclide calibrators - attendance at RCUF meetings

8. NPL database of calibrators used in hospitals

9. Set up RCUF web site on the NPL intranet site

UK radionuclide calibrator comparison exerciseUK radionuclide calibrator comparison exercise

1st RCUF meeting: 32P

Cost-sharing calibration exercise/comparison: 89SrUpdate list of possible participants

NMS current programme:

- Conduct two comparisons by Sep 2004

- Main delay: production/distribution of samples

(Amersham, AEA Technology)

- Advertise future comparisons: RAD, MPE mailbase, IPEM/BNMS

The Radionuclide Calibrator Users' Forum

The UK's National Measurement Laboratory

Advanced Search

Ionising Radiation

Research Program

Applications

Facilities

Science

Measurement Services

Contacts

Diary

Clubs & User Groups

Training & Workshops

Publications

Beginners Guide

Links to external sites

NPL Home

Science

E-Store

Publications

How can we improve the site for you?

The Radionuclide Calibrator Users' Forum Contact Us | Website Map

The Radionuclide Calibrator Users' Forum acts as a focal point for discussion of problems and dissemination of information between users of radionuclide calibrators. It enables participants to pool knowledge and share experience, thereby minimising any duplication of effort when problem solving and implementing best practice. The forum's activities are funded by the National Measurement System Policy Unit of the UK Government Department of Trade and Industry.

● A more detailed description of the forum's aims and activities can be found in the Terms of Reference.

Minutes of previous meetings available online:

Minutes of First Forum 31st Jan 2002

Presentations to First Forum, 31st January 2002:

● Chairman’s introduction (Mike Woods)● The Importance of a Copper Filter for Ionisation Chamber measurements of I123 and In111 Activity(Bill

Thomson)● Measurement of Kr81m generator output with an insert for an Ionisation Chamber; derived calibration factor

for a distributed Kr81m gas volume (Bill Thomson)● NPL current and past programme (Michaela Baker)

Dates of future meetings and workshops can be found in the Ionising Radiation Diary.

For more information contact Michaela Baker, CIRM, NPL

http://www.npl.co.uk/npl/rad/rcuf/ (1 of 2) [03/06/03 16:30:21]

RCUF web site:RCUF web site: http://www.npl.co.uk/npl/rad/rcuf/

NEXT:

- Minutes of this meeting

- List of NPL recommended half-lives for medical radionuclides

- List of calibration factors, volume correction factors for the

NPL calibrator

- Other proposals from this meeting

NPL database of calibrators used in hospitals:NPL database of calibrators used in hospitals:Questionnaire to be sent out (confidential)

Calibration factors for 10R Schott vialsCalibration factors for 10R Schott vials

- Does not fit in the std NPL holder

- 1.0 mm wall thickness

- 10 ml volume (shorter and wider)

- Inner coating of silica -eliminates adsorption losses (NPL measurements)

- Newly introduced

10R Schott vial10R Schott vial

- 1.2 mm wall thickness

- 10 ml volume

- Activity adsorption onto the glass vial: 5% to 19% (NPL calibrations)

- Standard container for activity measurements

P6 vialP6 vial

Calibration factors for 10R Schott vialsCalibration factors for 10R Schott vials

8.90 %4.563 MBq/g5.009 MBq/gCapintec 120 calibrator response for 125I:

10.8 %2.2013 pA/g2.4688 pA/gNPL calibrator response for 125I:

% differencefor 125I:

P610R Type 1+ Schott

10ml vial type:

Why:Why: The effect of the newly introduced 10R vials on the response of typical radionuclide calibrators

Calibration factors for 10R Schott vials:Calibration factors for 10R Schott vials: preliminary datapreliminary data

Radionuclide Average energy 10R Schott (pA/MBq) P6 (pA/MBq) % difference

18F 511 keV 10.391 10.35 0.39%32P 1.7 MeV * 0.0343 *51Cr 320 keV 0.3341 0.3327 0.42%67Ga 93keV; 185 keV; 300 keV1.565 1.547 1.15%85Sr 14 keV; 514 keV 5.286 5.258 0.53%89Sr 0.6 MeV; 1.5 MeV 0.0284 0.0279 1.76%90Y 0.5 MeV; 2.3MeV 0.0721 0.0678 5.96%99mTc 141 keV 1.24 1.227 1.05%111In 26 keV;171 keV; 245 keV4.129 4.088 0.99%123I 27-31 keV; 159 keV 1.721 1.685 2.09%125I 30-35 keV 0.4079 0.3706 9.14%131I 365 keV 4.074 3.999 1.84%131I capsule 364 keV 4.053 4.04 0.32%201Tl 60-80 keV; 167 keV 0.886 0.8557 3.42%

NEXT:NEXT: Further measurements to estimate the energy response, for impurity corrections

123123I activity assay with Copper filter insertI activity assay with Copper filter insert

Aim:Aim:

Calibration of the NPL calibrator, for 10R Schott vials

Characterisation of the commercial Copper filters (SS)

Cu insert dimensions:Cu insert dimensions:

H1 = 151 - 152 mm

H2 = ~250 mm

Thickness = 0.4 - 0.6 mmH

2H

1

123123I activity assay with Copper filter insert:I activity assay with Copper filter insert: preliminary datapreliminary data

Container, Measurement format Calibration figure Comments(pA/MBq)

10R Schott, vial holder 1.7210R Schott, Cu insert 1.34 Attenuation: 22.1 %10R Schott, Cu insert + vial holder 1.35 Attenuation: 21.5 %

NPL measurements:NPL measurements:

- 123I solution in: 2 x 10R Schott Type 1+ vials

- NPL secondary standard ionisation chamber

- Copper inserts from Southern Scientific

123123I activity assay with Copper filter insert:I activity assay with Copper filter insert: preliminary datapreliminary data

2.1 Vertical positioning of source in holder/well of ion chamber:

± 1.00 % (at k=1)

Uncertainty contributions:Uncertainty contributions:

1 Calibration factor: ± 1.00 % (at k=1)

2 Measurement format:

Cu insert height: ~ 250 mmVial holder height: ~ 200 mmIon chamber well height: ~ 400mm10R Schott vial height: ~ 45 mm

Cu insert: 22.1%

Cu insert+vial holder: 21.5%

123123I activity assay with Copper filter insert:I activity assay with Copper filter insert: preliminary datapreliminary data

2.2 Horizontal positioning of source in the ion chamber:

± 0.36 % (at k=1)NEXT: Further measurements required for better

estimation

2.3 Variation in wall thickness of the 10R Schott vial:

To be done

123123I activity assay with Copper filter insert:I activity assay with Copper filter insert: preliminary datapreliminary data

Thickness: 0.5 mm ± 0.1 mm

Thickness uncertainty: ± 0.058 mm (at k=1)

NPL ion chamber response with thickness of Cu insert:

Additional Cu foils

3 Tolerance on the thickness of Cu insert:

Approx: ± 1.00 % (at k=1)

Best practice:Best practice:Calibration of INDIVIDUAL COPPER FILTERS, Calibration of INDIVIDUAL COPPER FILTERS, for the preferred measurement formatfor the preferred measurement format

Further NPL projects with medical applicationsFurther NPL projects with medical applications

Accuracy of Accuracy of commercial radionuclide calibrators

Why:Why: Follow-up to measurement errors outlined by UK comparison exercises

0.50.60.70.80.91.01.11.21.31.41.5

Rep

orte

d va

lue/

NPL

val

ue

Reported P6 vial value/NPL value

Reported syringe value/NPL value

CAPINTEC Calibrator No[b] [b] [c] [d] [e] [e] [f] [f] [g] [g] [h] [h] [i] [i] [j] [j] [k] [k]

Accuracy of commercial radionuclide calibratorsAccuracy of commercial radionuclide calibrators

Containers used:Containers used:- 2 ml BS ampoule - 10R Schott vials- P6 vials- 2 ml Becton Dickinson

syringe- 5 ml Becton Dickinson

syringe

RadioRadio

nuclides:nuclides:67Ga 99mTc 111In 123I 131I 201Tl 125I 51Cr18F

Calibrators:Calibrators:- 1 x Capintec 120- 2 x Capintec 15R- 1 x NPL-CRC- 1 x Isomed 2000- 2 x Veenstra 202- 1 x Veenstra 304- 1 x PTW

1818F International comparisonF International comparison

Problem: Short Half-Life of 18F (1.828 hours)

Alternative route for equivalence:

NPL secondary standard calibrators used as transfer instruments:

- long-term stability

- available in many National Metrology Institutes

- almost identical responses

Why:Why:

To confirm the accuracy of the NPL primary standards of 18F

Increase use in positron emission tomography (PET) for

medical imaging

Further NPL projects with medical applicationsFurther NPL projects with medical applications

1818F F International intercomparisonInternational intercomparison

Comparison of 18F calibration figures (pA/MBq) determined for each calibrator instead of measured activities

Responses (pA) of individual calibrators were normalised to that of the NPL system using check sources of 68Ge (288 d) and its positron-emitting daughter 68Ga

10.3710.3710.5410.54

10[a]10[a]10[b]10[b]

10.5110.51

8[a]8[a]8[b]8[b]

10.3110.31

99

10.3810.3810.4910.4910.4210.4210.3910.3910.7410.7410.3610.3610.3910.39

Reported Reported 1818F F pA/MBq:pA/MBq:

NPLNPL665544221[a]1[a]1[b]1[b]

Participant Participant MNI No:MNI No:

Next: NPL submission of 18F to BIPM

Further NPL projects with medical applicationsFurther NPL projects with medical applications

18F international exercise – successful

Investigate the possibility of establishing a QA programme for short-lived radionuclides in the UK

Further NPL projects with medical applicationsFurther NPL projects with medical applications

Syringe calibration factors and volume correction factors Syringe calibration factors and volume correction factors

for the NPL secondary standard calibratorfor the NPL secondary standard calibrator

Why?

- Recommended syringe factors predominantly

overestimate the activity

- Wide variety of syringe types used routinely

NPL REPORT CIRM 56 NOW AVAILABLE !NPL REPORT CIRM 56 NOW AVAILABLE !

Further NPL projects with medical applicationsFurther NPL projects with medical applications

NPL calibration servicesNPL calibration services

AKR of LDR brachytherapy sources AKR of LDR brachytherapy sources -- NPL Secondary standard NPL Secondary standard ionisation chamber:ionisation chamber:

LDR LDR 192192Ir wires and hairpinsIr wires and hairpinsLDR LDR 125125I RAPID strands and single seeds I RAPID strands and single seeds –– recent additionrecent addition

Type of Source Model Number

Configuration in Jig

Air Kerma Rate Response [pA/µGy h-1 @ 1 m]

Calibration Figure Uncertainty % (at k=1)

Single seed

IMC6711 (OncoSeed)

Horizontal in trough

10.62

± 2.60 %

RAPID strand (Batch of 10 single seeds)

IMC7000 (OncoSeed)

Horizontal in trough

10.62

± 2.1 %