4th International Nuclear Chemistry Congress, Maresias, San Paulo-Brazil, September 14 - 19, 2014

Recovery of Actinium-225 and Radium-223

from Natural Thorium Irradiated with Protons

Elena.V. LAPSHINA, Stanislav V. ERMOLAEV, Boris L. ZHUIKOV, Aleksandr N. VASILIEV, Valentina S. OSTAPENKO, Ramiz A. ALIEV, Stepan N. KALMYKOV

Institute for Nuclear Research of Russian Academy of Sciences (Moscow, Russia)

Lomonosov Moscow State University, Chemistry Department (Moscow, Russia)

Slide 2

225Ac and 223Ra Properties Attractive for Nuclear Medicine

q  α-Particles have high linear energy transfer (up to 100 keV/µm) and a short pathlength (about 50-100 µm) in comparison with -particles

q   225Ac and 223Ra emit four α-particles each in the decay chains providing a higher impact to tumor cells

q   Intermediate half-lives of 225Ac and 223Ra (10.0 d and 11.4 d, respectively) are suitable for manufacturing and therapeutic treatment

q   225Ac and 223Ra may be also used as generators of the short-lived isotopes: 225Ac→213Bi (T1/2=46 min) and 223Ra→211Pb (T1/2=36 min) providing α-particles

Slide 3 Slide 3

High intensity linear accelerator Isotope production facility

Slide 4

Main Nuclear Reactions Resulting in 225Ac and 227Ac

232Th 231Th 230Th 229Th 228Th 227Th 226Th 225Th

233Pa 232Pa 231Pa 230Pa 229Pa 228Pa 227Pa 226Pa

224Ac

223Ra

225Ac 226Ac 227Ac 228Ac 229Ac 230Ac 231Ac

230Ra 229Ra 228Ra 227Ra 226Ra 225Ra 224Ra

232Th (p, x) 225Ac 232Th (p, p7n) 225Th (8 min, EC, 10%) → 225Ac 232Th (p, 4n) 229Pa (1.4 d, α, 0.48%) → 225Ac 232Th (p, x) 225Ra (14.8 d, β-, 100%) → 225Ac

225Ac

232Th (p, x) 227Ac

227Ac (chemically inseparable impurity)

Proton Energy up to 141 MeV

INR Accelerator Capacity for One 10-day Irradiation Run : 225Ac Activity 2.6 Ci 227Ac Impurity 0.2 % Decay after EOB 10 days (225Ac)

Slide 5

Main Nuclear Reactions Resulting in 223Ra and 224Ra

232Th 231Th 230Th 229Th 228Th 227Th 226Th 225Th

233Pa 232Pa 231Pa 230Pa 229Pa 228Pa 227Pa 226Pa

224Ac

223Ra

225Ac 226Ac 227Ac 228Ac 229Ac 230Ac 231Ac

230Ra 229Ra 228Ra 227Ra 226Ra 225Ra 224Ra

223Ra

232Th (p, p5n) 227Th 232Th (p, 6n) 227Pa (38 min, EC, 15%) → 227Th

224Ra (chemically inseparable impurity)

232Th (p, p4n) 228Th 232Th (p, 5n) 228Pa (22 h, EC, 98%) → 228Th 232Th (p, x) 228Ac (6.1 h, β-, 100%) → 228Th

228Th (1.91 a, α, 100%) → 224Ra (3.7 d) 227Th (18.7 d, α, 100%) → 223Ra

Proton Energy up to 141 MeV

INR Accelerator Capacity for One 10-day Irradiation Run : 223Ra Activity 4.5 Ci 224Ra Impurity 16 % Decay after EOB 16 days (223Ra)

Slide 6

Scheme of 223Ra Production via 227Th

0

2

4

6

8

10

0 5 10 15 20 25 30 35 40 45 50

Time, days

Act

ivity

, Ci

Irradiation Decay

227Th

223Ra

228Th

224Ra

Optimal decay time

Organic phase Th, Pa, Ru, Zr, Nb…

225Ac and 223Ra separation from irradiated 232Th

Eluate 4 M HNO3, Ra, Ba, Cs…

Wat

er p

hase

A

c, R

a, B

a, S

b, C

e…

Thorium Separation by extraction with tributyl phosphate (TBP), or

di(2-ethylhexyl)orthophosphoric acid (HDEHP) dissolved in toluene

Radionuclide separation on DGA Resin (N,N,N,,N,-tetroctyldiglicol amide)

Ac purification on TRU Resin (octylphenyl-N,N-di-

isobutylcarbomoylphoshine oxide)

Irradiated thorium target

Ac-225

Dissolution in 6 М HNO3 with addition of 4*10-3 M HF

DG

A

Ra - I Ra - II

Accumulation 223Ra from 227Th

Desorbate 0,01 M HNO3 Ac, La, Ce

Purification of Ra fraction

Slide 7

0

10

20

30

40

50

60

70

80

90

25 65 105 115 125 127 129 131 133 135 137

Аct

ivity

, %

V, ml

La

Ac

Ce

DGA Resin

Sorption – 6 М HNO3

Desorption – 0,01 М HNO3

TRU Resin

Sorption and Desorption – 2 М HNO3

225Ac: Isolation and Purification by Extraction Chromatography

Column: d=0.35cm, h=8 cm V(TRU Resin)= 0.17 ml/min

Slide 8

223Ra (I): Re-extraction from Organic Phase and Purification

Slide 9

TBP

HDEHP Water fraction Ra > 99%

Ru, I < 1% - may be removed by evaporation with HClO4

Organic fraction

Ce, Nb, Zr, Pa, Th, Ru > 99%

Ce ThPa

IRu

ZrNb

5

7

9010203040

50

60

70

80

90

100HCl

Ce ThPa

IRu

ZrNb

5

7

9010203040

50

60

70

80

90

100 HNO3

Re-

extr

actio

n, %

Acidity, mole/L

Slide 10

0%

10%

20%

30%

40%

50%

60%

70%

0 5 10 15 20 25 30 35 40 45

Act

ivity

Ra 223 Cs 136 Ba 140 Ru 103 La 140 Te 123m Be 7 Sb 124

Volume, mL

Ra,  Ba  

Cs, Be

Te  Ru, Sb, Te

La

H2O 0,5 M H2SO4 H2O 2 M HNO3 4 M HNO3

Column: d=0.8cm, h=7 cm V= 0.5 ml/min

223Ra (II): Isolation of Ra from DGA eluate on Dowex-50x8

223Ra (II): Distribution Coefficients of Radium and Barium on Sr Resin (dicyclohexano 18-crown-6 derivative in octanol)

E.  P.  Horwitz,  R.  Chiarizia  and  M.  L.  Dietz,  Solvent  Extr.  Ion  Exch.  1992,  Vol.  10,  pp.  313-­‐336.  

Slide 11

Slide 12

0%

10%

20%

30%

40%

50%

60%

0 5 10 15 20 25

Act

ivity

Ra 223 La 140 Ru 103

0,5 М HClO4 2 М HNO3

La, Ru Ra

3 M HNO3

223Ra (II): Isolation of Radium on Sr Resin

0%

10%

20%

30%

40%

50%

60%

0 5 10 15 20 25

Act

ivity

Ra 223 La 140 Ru 103 Ba 140

Ba

Volume, ml

Column: d=0.8cm, h=7 cm

V= 0.6 ml/min

Ra

Ru La

Scheme of 223Ra separation

I.  Solu(on  HDEHP  in  toluene  (1:1)  a6er  liquid-­‐liquid  extrac(on  

 Re-­‐extrac(on  (  a6er  20  days)    

223,224Ra,    Ru,  I  

 Separa(on  Ru,  I  by  HClO4  

 

223,224Ra,  Th,  Pa,  Zr,  Nb,  Ru    

Ra  

II.  Solu(on  from  DGA  Resin,  0,01  M  HNO3:    223,224Ra,  Cs,  Ba,  La,  Sb,  Te,  Nb,  Ag    

Ca(on  exchange  resin  Dowex  50  х  8  

Sorbent  Sr-­‐resin    

Slide 13

223,224Ra,    Ba  

Slide 14

Conclusions

q   INR accelerator can provide 2.6 Ci of 225Ac and 4.5 Ci of 223Ra during a 10-day irradiation.

q   Radiochemical procedures for separation 225Ac and 223Ra from spallation and fission products generated in the irradiated thorium target have been developed.

q   This procedures provide a good chemical yield 80-90% and high radionuclidic purity (99.9%) suitable for medical applications.

Slide 15

Acknowledgement

The authors are grateful to:

q   Dr. Steffen Happel and TrisKem International company for

providing the samples of extraction chromatography resins

q   Karpov Institute of Physical Chemistry located in Obninsk for the help in processing thorium targets in hot cells.

Thank you for attention! J

16

17

 

Вода Ac-фракция

Li <2 <2 Be <0,01 0,033 B 6,9 5,6 Al 0,68 20 V 0,02 0,20 Cr <0,1 10 Mn 0,25 3,7 Co <0.02 0,15 Ni <0.02 10 Cu 0,15 12 Zn 1,0 53 As <0,2 <0,2 Sr <0,05 1,7 Ag 0,045 0,23 Cd <0,01 0,16 Sb 0,023 0,11 Cs <0,01 0,026 Ba 0,14 3,3 Tl <0,005 <0,005 Pb 0,12 18 Bi <0,02 <0,02 Th <0,02 2,0 U <0,002 0,30

Water   Ac-­‐frac(on  mg/l  

18

•  Ln Resin •   TRU Resin

•   DGA Resin M3+ + 3(NO3)- +3DGA = M(DGA)3 (NO3)3 M4+ + 4(NO3)- +2DGA = M(DGA)2 (NO3) 4

M3+ + 3 HY MY3 + 3H+

M3+ + 3(NO3)- + 3 E M(NO3)3 * E3