Cyclotron Production of I-123 by Bombardment of 124Te Electroplated Target

Zhou Wei, Wang Yongxian, Yin DuanzhiShanghai Institute of Applied Physics,

Chinese Academy of Science

Nuclear process for production of 123I

Direct method: (low energy cyclotron) 121Sb(α,2n)123I, natSb(3He,xn)123I,124Te(p,2n)123I, 123Te(p, n)123I,122Te(d,2n)123I ……

Indirect method: 123Xe 123I(medium and high energy cyclotron)127I(p, 5n)123Xe, 124Xe(p, 2n)123Xe124Xe(p, pn)123Xe ……

Te target for production of I-123

Metal 124Te target2π or 4π cooling wet chemical separation Molten 124TeO2 target4π coolingdry distillation

Source for 124TeO2 lost

Target heating to liberate 123Iloss of 124TeO2:<1%Accidental melting during irradiation2π cooling systemirradiation angle: 6 ºloss of 124TeO2:3~5%

Production methodfor electroplated target

124Te electroplated Target----molten target

Irradiation

Wet chemical separation -----dry distillation

Recovery of the enriched tellurium

Quality control

Targetry Ni surface onto the Cu plate

Ni plating solution:

NiSO4·6H2O

NiCl2·6H2O

H3BO3

pH: 3~4.

TargetryNi surface onto the Cu plate

Current: 200mATime: 12 min Anode: platinum electrodeCathode: Cu plateCurrent efficiency: 90%Ni thickness: 250ug/cm2

Targetry Electroplating of enriched 124Te

Stock solution124Te 124Te O 2

KOH solutionpH: 10~11

Targetry Electroplating of enriched 124Te

Current:100mATime: 60 minThickness: 12mg/cm2

WashDry

124Te electroplated target

Irradiation

Cyclone 30 (IBA)Proton energy: 25 MeVBeam current intensity: 20~50µA Time of irradiation: 0.5~3hr 123I yield: 8.2mCi/µA h124Te loss: <1% each run

Separation of I-123 from tellunium

Dissolution of 124Te(NaOH+ H2O2)Aluminum powerHeating gentlyStream distillationPrecipitation (Te0 +Al(OH)3)FilterRadiochemical yield : >90%

Recovery of the enriched Te-124

Dissolution of power(Te0 +Al(OH)3)H2SO4 + H2O2

DistillationHypophosphorus acidPrecipitate of telluriumwashed and dried124Te recovery : >99.5%

Quality ControlRadionuclidic purity

Radioactivity concentration

Radiochemical purity

pH value

Concentration of Al & Te

Bacterial endotoxins

Result and discussionTargetthickness: Ni 250ug/cm2, Te 12mg/cm2

123I yield: 8.2mCi/µA hr124Te loss: 1% each runRadiochemical yield : >90%124Te recovery : >99.5%

Influence of beam current intensity on loss of Te

10 20 30 40 50 60 70 80 90 100 1100.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Loss

of T

e (%

)

Beam current intensity (uA)Fig.1 Relationship between loss of Te and beam current intensity

Influence of thickness of Ni layeron loss of Te

100 150 200 250 300 350 4000.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

loss

of T

e (%

)

thickness of Ni layer (ug/cm2)Fig.2 Relationship between loss of Te and thickness of Ni layer

124Te(p,2n)123I 50uA, 1hr

Influence of thickness of Te on loss of Te

9 10 11 12 13 14 15 160.0

0.5

1.0

1.5

2.0

2.5

124Te(p,2n)123I 50uA, 1hr

loss

of T

e (%

)

thickness of Te(mg/cm2)Fig.3 Relationship between loss of Te and thickness of Te

Influence of thickness of Te on yield of 123I

10 11 12 13 14 155

6

7

8

9

10

11

124Te(p,2n)123I50uA, 1hr

yiel

d(12

3 I mC

i/uA

hr)

thickness of 124Te(mg/cm2)

Fig.4 Influence of thickness of 124Te on yield of 123I

Influence of integrated current on yield of 123I

0 50 100 150 2003

4

5

6

7

8

9

10

Yiel

d (m

Ci12

3 I/uA

hr)

Integrated current(uAhr)Fig.5 Relationship between yield of 123I and integrated current

124Te(p,2n)123I124Te target: 13mg/cm2

Specification of 123I solution

Radionuclidic purity: >98%.

Radiochemical purity: Iodide 123I >95%

Radioactivity concentration: >3700 MBq/mL.pH value: 7.5~9.0Concentration of Al: < 1ug/mLConcentration of Te: <1ug/mLBacterial endotoxins: <30EU/mL

Thank you for your attention!