Microsphere Loading Device

This invention relates to a device for transferring radioactive microsphere suspensions from storage containers to test apparatus.

The measurement of blood flow to various regions of the body is used to measure performance of animals in test programs. Radioactive microspheres are used to measure blood flow to body organs and tissue. To provide accurate measurements, it is necessary to accurately measure and transfer the radioactive microsphere suspension to the test equipment.

According to this invention, a microsphere loading device is provided wherein a three way stopcock is connected between a 1 ml loading springs, a 5 ml washing syringe and a two inch cannula hypodermic needle.

After the radioactive microsphere suspension is drawn into the 1 ml syringe and injected into the test apparatus, the 5 ml syringe is used to provide three washes for the 1 ml syringe to insure that no radioactive microspheres are left in the microsphere loading device.

FIG. 1 is an isometric view of the microsphere loading device of the invention.

FIG. 2A is a schematic illustration showing the three way stopcock, of FIG. 1, in the microsphere suspension transfer position.

FIG. 2B shows the three way stopcock in its wash transfer position.

FIG. 2C shows the three way stopcock in its needle flushing position.

FIG. 3 is an enlarged view of the hypodermic needle of the device of FIG. 1 .

Reference is now made to FIG. 1 of the drawing which shows a microsphere loading device 10, having a three way stopcock 12, a 5 ml syringe 14, a 1 ml syringe 16 and a two inch cannula hypodermic needle 18. The syringe 16 and the needle 18 are connected to the three way stopcock 12 with conventional Luer-lok connectors 20 and 22. The syringe 14 is connected to the three way stopcock by means of a connector 24 and Luer-lok 26. In the device constructed the connector 24 was a conventional three way stopcock similar to stopcock 12 but with the adjusting handle removed and the Luer-lok fitting corresponding to fitting 20 removed and with the hole plugged.

The needle connector 30 has grooves 32 provided to permit the escape of air while transferring microsphere solution and wash solution to the test apparatus.

In the operation of the device of the invention, the desired amount of radioactive suspension such as radioactive iodine, chromium, cerium, scandium or strontium in a dextran solution is drawn into the 1 ml syringe and deposited in the test apparatus. The long cannula needle permits filling the test apparatus from the bottom up to assure that no air bubbles are left in the test apparatus. The air passages 32 permit escape of air from the test apparatus during filling. After the microsphere solution is deposited into the test apparatus, the valve 12 is turned to the position shown in FIG. 2B and a wash solution such as a normal saline solution is transferred from syringe 14 to syringe 16. The level of the wash solution in syringe 16 should be higher than the level of the microsphere solution to remove any residual microsphere solution. The stopcock 12 is then turned to the position shown in FIG. 2A and the wash in syringe 16 is transferred to the test apparatus in the same manner as the microsphere solution. This procedure is then repeated for two additional washings of syringe 16 with each washing being at a higher level than the previous washing. After the three washings of syringe 16, the stopcock 12 is positioned as shown in FIG. 2C and additional washing solution is transferred to the test apparatus to provide a thorough wash for the needle 18 and to fill the test apparatus to the desired level.

The outputs 20', 22' and 26' correspond to the Luer-lok connections 20, 22 and 26 in FIG. 1. In the use of the microsphere loading device, all of the parts of the loading device were measured for residual microspheres with a gamma counter. The tests resulted in the safe transfer of a specified amount of radioactive microspheres.

There is thus provided a device for the safe and accurate loading of a radioactive microsphere solutions in test apparatus.