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Extraction chromatography method for the separation of Extraction chromatography method for the separation of

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Extraction chromatography method for the separation of - PPT Presentation

155 Tb from radionuclide impurities for primary standardisation nuclear data measurements and SPECT imaging MEDICIS Promed Final Conference 30 April 4 May 2019 Erice Sicily ID: 801549

separation 155tb npl resin 155tb separation resin npl life determined 155 imaging spect measurements nuclear data performed primary uteva

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Slide1

Extraction chromatography method for the separation of

155Tb from radionuclide impurities for primary standardisation, nuclear data measurements and SPECT imaging

MEDICIS-Promed Final Conference, 30 April – 4 May 2019, Erice, Sicily

Peter Ivanov

National Physical Laboratory, UK

Slide2

Why terbium?161TbBeta/Auger therapySPECT diagnostics6.89 d

155TbSPECT diagnostics

5.32 d 152Tb

PET diagnostics

17.5 h

149

Tb

Alpha therapy

4.12 h

Decay Mode

Half-life

MRT Application

149

Tb

a

,

b+

(17%,

7%)

4.12 hours

Therapy

(

a

)

152

Tb

b

+ (17%)

17.5 hours

PET Imaging

155

Tb

EC (100%)

5.32 days

SPECT Imaging

161

Tb

b

- (100%)

6.89 days

Therapy (

b

-)

Slide3

Production of 155Tb at CERN

Proton-induced spallation reactionTantalum target

On-line mass separation at 155 m/qIsotopes collected in a zinc-coated gold disc

Slide4

Impurities139LaSTABLE155Gd

STABLE155

Eu4.75 aBeta- decay155

Dy

Electron Capture

9.9 h

139

Ce

Electron Capture

137.6 d

155

Tb

Electron Capture

5.3 d

Slide5

Method developmentUsing stable element standards (159Tb, 140Ce)

ICP-MS analysisOxidation of ceriumChromatographic separation from HNO

3- Resin studies- Kinetic studiesColumn separation

=

 

(CPS)

0

= counts per second

before

contact with resin

(CPS)

t

= counts per second

after

contact with resin

V

= volume of HNO

3

(mL)

m

= mass of resin used (g)

Selective oxidation of cerium

:

Ce(III)

 Ce(IV)

Tb(III)  Tb(IV)

Slide6

Ce(III) selective oxidationNaBrO3 oxidantCerium adsorption increasedSuggests that cerium is oxidised

Slide7

Chromatography resin studiesStatic conditions, stable tracers24 h equilibrium timeTEVA, UTEVA and TK100 extraction resins

AG1-X8 anion exchange resin

Best separation using:UTEVA or TEVA

resin

High HNO

3

concentrations

TEVA

UTEVA

Slide8

Elution profilesPre-packed 2 mL UTEVA cartridgeTerbium collected with 8 M HNO3Cerium eluted from column in 0.1 M HCl

Elution profile @ flow rate ~ 0.3 mL/min

Slide9

Separation procedure

STEP 1

: Foil dissolutionSTEP 2: Removal of Tb and Ce from Au and Zn matrixSTEP 3: Isolation of Tb from CeSTEP 4: Conversion of Tb to chloride form

Slide10

Active sampleNo 139Ce detected after separation

Supplied

155

Tb = ~ 8.1

MBq

Before

separation =

After

separation =

 

Slide11

155Tb Primary standardisationSchematic of the NPL 4π(Liquid Scintillation)-γ(HPGe) Digital Coincidence Counting system Preliminary activity at the reference time (572.7 ± 2.9) kBq g-1 (k = 1)

A set of six sources measured For each the LSC channel efficiency varied by computer discrimination methodThe activity determined

by extrapolating to 100 % efficiency

Slide12

155Tb Half-life measurementThe radioactive decay rate of 155Tb was observed over 18.6 days (or approximately 3.55 half-lives) using a HPGe γ-ray spectrometer. A total of 131 measurements were made.From each measurement the sum of the net peak areas of the 86.6 keV and 105.3 keV full-energy peaks was determined.

A non-linear weighted least squares fit was performed to the measured data points using the equation:

Slide13

155Tb Half-life measurement Half-life of 155Tb determined in this work and the uncertainty budget Comparison of published half-life determinations of 155Tb

Slide14

155Tb Emission probabilitiesThe normalised emission intensities of 89 emissions have been determined Standard uncertainties have been typically reduced by a factor of four [4] Reich, C. W., 2005. Nuclear data sheets for A = 155. Nuclear Data Sheets 104, 1-282.

Slide15

155Tb SPECT ImagingDetails in Sophia Pells’ presentation Quantified nuclear medicine imaging of 155Tb siemens-healthineers.com

Slide16

Column separation – Dy/Tb/Gd Stable elemental tracers & ICP-MS analysisLN resin Column volume ~8 mLFlow rate ~ 1 mL/min

(Semi-)Automated Lanthanide Separation

Slide17

Highly efficient chemical separation method has been derived for removing the 139Ce impurity from the 155Tb (Submitted to Nature Scientific Reports)The world first primary standardisation of the potential theranostic SPECT radionuclide 155Tb has been performed at NPL which will provide traceability of the administered activities for any pre-clinical and clinical trials performed in the future.A precise half-life of 155Tb has been determined, which was found to have a 1.5 % relative difference to the current recommended value. A factor of 5 increase in the precision over previous measurements has been achieved.Precise measurements of the emission intensities of 89 -ray transitions have been performed. These make significant revisions to the currently recommended values with improved precision.

Conclusions

Slide18

Acknowledgements

Chemical separation

Ben Webster (Surrey/NPL)ICP-MS analysis Ben Russell (NPL)

Active

Samples

Thierry

Stora,

Joao Pedro Ramos (CERN) Ulli Köster (ILL)Gamma Spectrometry

Sean Collins (NPL

)

Primary standardisation

Arzu

Arinc

, John Keightley (NPL)

SPECT Imaging

Andrew Robinson (NPL

)

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654002

Thank you for your attention! Questions?