Method of preparing a radiodiagnostic comprising a gaseous radio

Details Method of preparing a radiodiagnostic comprising a gaseous radio Method of preparing a radiodiagnostic comprising a gaseous radio

1992-01-23

1993-10-19

Stoll, Robert L.

Drug, bio-affecting and body treating compositions

Radionuclide or intended radionuclide containing; adjuvant...

423 2, 250432PD, A61K 4300, C01G 5700

Patent

active

052543285

DESCRIPTION:

BRIEF SUMMARY
The invention relates to a method of preparing a radiodiagnostic comprising a gaseous radionuclide formed by radioactive decay of a parent nuclide, by eluting with a suitable eluent the radioactive daughter nuclide from the parent nuclide provided ionically on a carrier.
Such radiodiagnostics are intended in particular for lung function examination and regional blood circulation measurements. Examples of gaseous radionuclides are radioactive noble gases which can be eluted inter alia with gaseous eluents, for example, oxygen or air, and are then suitable for pulmonary ventilation studies. For example, in combination with lung perfusion scintigraphy, lung defects, like pulmonary embolies, obstructions in the bronchi and the like, can in this manner be detected and localised in a simple manner.
A radioactive noble gas to be considered for such an examination is radioactive krypton, in particular krypton-81m (.sup.81m Kr). Krypton-81m which has been available for a few years already, has favourable radiation characteristics, for example, a half life of only 13 seconds and the absence of beta rays. Due to the many favourable properties of krypton-81m, physical and chemical as well as physiological, there is hence an increasing interest for the use of this radionuclide in radiodiagnostics, in particular for pulmonary ventilation studies and regional blood circulation measurements. However, krypton-81m may also be used for example for lung perfusion scintigraphy, although technetium-99m compositions are often preferred for such applications. It may be desirable for such applications to have the disposal of a liquid radiodiagnostic. For this purpose liquid eluents may be used, for example, a 5% glucose solution, to elute krypton-81m from the parent nuclide, i.c. rubidium-81 (.sup.81 Rb), provided on a carrier.
A device in which a radioactive daughter nuclide is formed by radioactive decay of a parent nuclide and can then be eluted is termed a radonuclide generator. Various generators are known for generating radiodiagnostics comprising gaseous radionuclides, in particular krypton-81m. Such generators should be suitable for elution with air or oxygen, after which the gas enriched with krypton-81m must be inhaled immediately by the patient in connection with the short half life of the radionuclide. By situating suitable detection apparatus, for example, a gamma camera, near the patient during said inhalation, a study can be made of, for example, the patient's lung function. In the systems most in use the parent nuclide is provided on an adsorption agent in a column in which during the elution the gaseous eluent is allowed to flow through the column. As adsorption agents for the column are to be considered ion exchanging resin beads and zirconium phosphate, for example, as indicated in publications of Mostafa et al (J. Nucl. Med. 24, 157-159, 1983) and of Beyer et al (Int.J.Appl.Radiat.Isot. 35, 1075-1076, 1984). During the elution the gaseous daughter nuclide, i.c. krypton-81 m, is entrained by the gas flow while the parent nuclide, i.c. rubidium-81, must remain behind on the column. However, as a result of the presence of a pressure drop over the packed column, the elution efficiency is detrimentally influenced and in certain circumstances may even be some tens of percents lower than the maximally achievable yield. An improvement can be achieved by using a humidifying system to humidify the gaseous eluent prior to elution; also in the system described by Mostafa et al a humidifier is used. Apart from the fact that an elution efficiency which is satisfactory in every respect is not yet achieved by humidifying the air or oxygen, other disadvantages are introduced by the use of a humidifier: the system becomes more complicated and the purity (asepsis) of the air or oxygen to be used for elution may be compromised. The elution efficiency can be considerably improved by causing the gaseous eluent to flow through the adsorption column at a lower rate. However, the residence time of the eluate, i.e. of the air or oxygen

REFERENCES:
patent: 3446965 (1969-05-01), Ogier et al.
patent: 3740558 (1971-02-01), Kato et al.
patent: 3774036 (1973-11-01), Gerhart
patent: 3902849 (1975-09-01), Barak et al.
patent: 4876076 (1989-10-01), Issachar et al.

Affiliated with

Also associated with

Rating

Method of preparing a radiodiagnostic comprising a gaseous radio does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method of preparing a radiodiagnostic comprising a gaseous radio, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of preparing a radiodiagnostic comprising a gaseous radio will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1349891