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)
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 2
High intensity linear accelerator
Isotope production
facility
Slide 3
Main Nuclear Reactions Resulting in 225Ac and 227Ac
226Pa
227Pa
228Pa
229Pa
230Pa
231Pa
232Pa
233Pa
225Th
226Th
227Th
228Th
229Th
230Th
231Th
232Th
224Ac
225Ac
226Ac
227Ac
228Ac
229Ac
230Ac
231Ac
Proton Energy
up to 141 MeV
INR Accelerator Capacity for
One 10-day Irradiation Run :
223Ra
224Ra
225Ra
226Ra
227Ra
228Ra
225Ac
229Ra
230Ra
225Ac
Activity
2.6 Ci
Impurity
0.2 %
Decay after EOB 10 days (225Ac)
227Ac
227Ac
(chemically inseparable impurity)
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
232Th
(p, x) 227Ac
Slide 4
Main Nuclear Reactions Resulting in 223Ra and 224Ra
226Pa
227Pa
228Pa
229Pa
230Pa
231Pa
232Pa
233Pa
225Th
226Th
227Th
228Th
229Th
230Th
231Th
232Th
224Ac
225Ac
226Ac
227Ac
228Ac
229Ac
230Ac
231Ac
Proton Energy
up to 141 MeV
INR Accelerator Capacity
for One 10-day Irradiation Run :
223Ra
223Ra
224Ra
225Ra
226Ra
227Ra
223Ra
232Th
(p, p5n)
227Th
232Th
(p, 6n)
227Pa
227Th
228Ra
229Ra
230Ra
Activity
4.5 Ci
224Ra
Impurity
16 %
Decay after EOB 16 days (223Ra)
224Ra
(chemically inseparable impurity)
232Th
(38 min, EC, 15%) → 227Th
(18.7 d, α, 100%) → 223Ra
(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)
Slide 5
Scheme of 223Ra Production via 227Th
10
Irradiation
Decay
Activity, Ci
8
Optimal
decay time
227Th
6
223Ra
4
2
228Th
224Ra
0
0
5
10
15
20
25
30
35
40
45
50
Time, days
Slide 6
225Ac
and 223Ra separation from irradiated 232Th
Irradiated thorium target
Organic phase
Th, Pa, Ru, Zr, Nb…
Accumulation 223Ra from 227Th
DGA
Thorium Separation by extraction
with tributyl phosphate (TBP), or
di(2-ethylhexyl)orthophosphoric acid
(HDEHP) dissolved in toluene
Water phase
Ac, Ra, Ba, Sb, Ce…
Dissolution in 6 М HNO3 with
addition of 4*10-3 M HF
Radionuclide separation on DGA Resin
(N,N,N,,N,-tetroctyldiglicol amide)
Eluate 4 M HNO3,
Ra, Ba, Cs…
Purification of Ra fraction
Ra - II
Ra - I
Desorbate 0,01 M HNO3
Ac, La, Ce
Ac purification on TRU Resin
(octylphenyl-N,N-diisobutylcarbomoylphoshine
oxide)
Ac-225
Slide 7
225Ac:
Isolation and Purification by Extraction Chromatography
DGA Resin
TRU Resin
Ac
Sorption – 6 М HNO3
90
Sorption and Desorption – 2 М HNO3
Desorption – 0,01 М HNO3
80
70
La
Аctivity, %
60
Ce
50
40
30
Column: d=0.35cm, h=8 cm
V(TRU Resin)= 0.17 ml/min
20
10
0
25
65
105
115
125
127
129
131
133
135
137
V, ml
Slide 8
223Ra
(I): Re-extraction from Organic Phase and Purification
TBP
n, %
Re-extractio
100
100
HCl
90
HNO3
90
80
80
70
70
60
60
50
50
40
40
30
30
20
20
10
10
0
9
Ce
Th
Pa
7
I
Ru
0
9
Ce
5
Zr
Nb
Water fraction
Ra > 99%
Ru, I < 1% - may be removed
by evaporation with HClO4
HDEHP
Th
Pa
7
I
Ru
5
Zr
Nb
Acidity,
mole/L
Organic fraction
Ce, Nb, Zr, Pa, Th, Ru > 99%
Slide 9
223Ra
(II): Isolation of Ra from DGA eluate on Dowex-50x8
Column: d=0.8cm, h=7 cm
V= 0.5 ml/min
70%
H 2O
0,5 M H2SO4
H 2O
2 M HNO3
4 M HNO3
60%
Ra 223
50%
Cs 136
Cs, Be
Ba 140
40%
Ru 103
Activity
Ra, Ba La 140
Ru, Sb, Te
30%
Te 123m
Te Be 7
20%
Sb 124
La
10%
0%
0
5
10
15
20
25
30
35
40
45
Volume, mL
Slide 10
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
223Ra
(II): Isolation of Radium on Sr Resin
60%
3 M HNO3
La
50%
Ru
40%
Activity
Column: d=0.8cm,
h=7 cm
V= 0.6 ml/min
Ba
30%
Ra 223
20%
La 140
Ra
Ru 103
10%
Ba 140
0%
0
10
Volume, ml15
0,5 М HClO4
60%
20
25
2 М HNO3
La, Ru
50%
Activity
5
Ra
Ra 223
40%
La 140
30%
Ru 103
20%
10%
0%
0
5
10
15
20
25
Slide 12
Scheme of
223Ra
I. Solu(on HDEHP in toluene (1:1) a6er liquid-­‐liquid extrac(on separation
II. Solu(on from DGA Resin, 0,01 M HNO3: 223,224Ra, Cs, Ba, La, Sb, Te, Nb, Ag 223,224Ra, Th, Pa, Zr, Nb, Ru Ca(on exchange resin Dowex 50 х 8 Re-­‐extrac(on ( a6er 20 days) 223,224Ra, Ru, I 223,224Ra, Ba Sorbent Sr-­‐resin Separa(on Ru, I by HClO4 Ra Slide 13
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 14
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.
Slide 15
Thank you for attention! J
16
mg/l Li
Be
B
Al
V
Cr
Mn
Co
Ni
Cu
Zn
As
Sr
Ag
Cd
Sb
Cs
Ba
Tl
Pb
Bi
Th
U
Вода
Water <2
<0,01
6,9
0,68
0,02
<0,1
0,25
<0.02
<0.02
0,15
1,0
<0,2
<0,05
0,045
<0,01
0,023
<0,01
0,14
<0,005
0,12
<0,02
<0,02
<0,002
Acфракция
Ac-­‐frac(on <2
0,033
5,6
20
0,20
10
3,7
0,15
10
12
53
<0,2
1,7
0,23
0,16
0,11
0,026
3,3
<0,005
18
<0,02
2,0
0,30
17
•   Ln Resin
M3+ + 3 HY
MY3 + 3H+
•   TRU Resin
M3+ + 3(NO3)- + 3 E
M(NO3)3 * E3
•   DGA Resin
M3+ + 3(NO3)- +3DGA = M(DGA)3 (NO3)3
M4+ + 4(NO3)- +2DGA = M(DGA)2 (NO3) 4
18