Abstract |
123I, which is applied for the thyroid and other in
vivo kinetic study, has a special role in life
sciences. The 159 KeV r-ray from 123I is almost ideally
appropriate for the current imaging instrurnentation.
Its decay mode (electron capture) and short half-life
(13.3 hr) reduced the burden of radiation dose to the
patients, and its chemical property makes it easy to
synthesize the labelling compounds. In this experiment,
the production of 123I via the nuclear reaction
124Te(p,2n)123I with 28 MeV protons was sutdied. TeO,
is used as a target material, because it has goad
physical properties. The target was prepared with TeO,
powder and was rnolten into a ellipsoidal cavity
(a=14mm, b=10 mm, 270.8 mg/cm thick) of pure platinum.
The irradiation was carried out in the external proton
beam with incident energies range from 28 MeV to 22
MeV, and current was 30pA. The loss of TeO, target was
significantly reduced by using 4-cooling system in
irradiation. The dry distillation method was adopted
for the separation of 123I from irradiated target, and
when it was kept 5 minutes at 780C, its result was
quantitative. The loss of the target material (TeO,)
was below 0.2% for each production run and 'I from the
dry distillation apparatus was captured with 0. 01 N
NaOH in NaI form, then the pH of the solution was
adjusted to 7.5-9.0 with HC1/NaOH. The Na123I solution
was passed through 0.2pm membrane filter, and
sterilized under high pressure and temperature for 30
minutes. The prodvction of 'I is acceptable for
clinical application based on the quality of USP XXI. |