Radioisotope Generator Of The Mother-daughter Type Having Quick-detachable Members

Abstract

A device is disclosed for obtaining fluids containing radioactive constituents particularly suitable for medical purposes. The device includes a holder for a substance having radioactive constituents and which is providing at the upper and lower ends with a portion of a quick-coupling member. In operation a vessel for a flushing liquid is connected with the upper coupling portion and the vessel for the fluid to be collected is connected with the lower coupling member portion to facilitate washing of the holder and collection of the fluid from the holder while avoiding contamination of the fluid in the holder.

Description

The invention relates to a device comprising a detachable holder for a substance having radioactive constituents, into which holder, in operation, a washing fluid is introduced at the upper end, while a fluid containing radioactive constituents, particularly suitable for medical purposes is obtained from the lower end of said holder and collected in a vessel.

In such a device the holder may contain a radioactive mother substance bound, for example, to an ion exchanger, for instance molybdenum-99 or germanium-68, which decays with time by radiation into a radioactive daughter substance having a shorter half-value period than the mother substance, for example, Technicium-99m or gallium-68. These daughter substances suitable for various medical purposes. They may be injected as liquid suspensions into the blood vessels of the human body, where they provide by their radiation measurable data about physical procedures and conditions of body organs.

By washing the contents of the holder with a flush which carries along the daughter substance, the desired product of the device, formed by a fluid having the daughter substance is obtained.

A known device of this kind comprises a holder with the mother substance, also termed the generator, which holder is open at the bottom and whose closure at the top is removed for introducing the washing fluid. Beneath the holder an open vessel is arranged. In operation the holder and the vessel of that device are usually screened at least partly, for example by a lead jacket. During the washing operation, that is to say, when the flush is poured in and the product is collected, the upper end and the lower end of the holder and also the collecting vessel remain open. This known device has the advantage that it allows quick manipulation, which is important for avoiding a noxious effect of the radiation on the operator or persons standing by. This advantage is particularly appreciated in preparing the device for operation, for example, when the generator is taken out of its packing and introduced into the device and during the washing operation itself.

The product of the device, the fluid containing the daughter-substance or eluate, has to fulfill, because of its medical use, the requirements of being sterile and pyrogen-free. The known device has the disadvantage that it cannot fulfill this requirement without the need for further steps. Since the holder and the collecting vessel are open during the washing operation, infecting substances are freely accessible to the product. It is therefore necessary to subject the product of this known device to a sterilizing treatment before use. This may be particularly disadvantageous, when the half-value period of the radioactive product is only little longer than the period of time required for sterilization. It is even not possible to use for medical purposes the radioactivity of the eluates obtained by the known device, if these eluates have a half-value period approximately equal to or shorter than the required period of sterilization.

The invention has for its object to provide a device for obtaining fluids containing radioactive constituents particularly suitable for medical purposes, by which the disadvantages of the known device described can be avoided and the said advantages are maintained. A device of the kind set forth according to the invention is characterized in that the holder is provided at the upper end and at the lower end with a portion of a quick-coupling member, while in operation a vessel for the flushing liquid is connected with the upper coupling member portion and the vessel for the fluid to be collected is connected with the lower coupling member portion.

By employing quick coupling members the advantage of easy and rapid operation of the device according to the invention is maintained. A further advantage of the device according to the invention consists in that during washing the holder and the vessels communicate with each other, so that the fluids and the contents of the holder are not accessible for particles from the environments. This means that, it being assumed that the conventional steps are taken such as the use of presterilized, pyrogen-free washing fluid, vessels and coupling members, the device can provide from a sterile, pyrogen-free generator a sterile and pyrogen-free product directly suitable for medical use. Subsequent sterilization of the product may be dispensed with. Even daughter substances having a very short half-value period may be employed.

One embodiment of the device according to the invention is characterized in that a portion of the holder coupling member is formed by a pierceable wall portion of the holder and a coupling portion that can be connected herewith is formed by a hollow needle. The pierceable wall portion may be formed by a rubber plug, arranged on the holder, for example, of glass and sealed at the edge by a flanged capsule. The needle may be an injection needle. These parts are known from the medical apparatus technology. By said parts a quick-coupling can be established in a very simple manner between the holder and a vessel. Other kinds of quick-coupling members may, of course, be employed, such as those known for the detachable connection of an injection needle with the body of an injection syringe.

The possibility of ready manipulation, especially of the radioactive parts of the device is improved in a further embodiment which is characterized in that a coupling portion adapted to be connected with a coupling portion of the holder is fastened to the end wall of an approximately box-shaped element, which is open at one end and surrounds the holder at least partly with small clearance in the operation of the device. The box-shaped element, previously sterilized in the conventional manner, may be fastened in or inserted into the device (for example through an opening of a lead jacket), after which the generator can be simply inserted into this element, while at the same time the connection of the coupling concerned can be rapidly established. The device according to the invention may be furthermore characterized in that in operation the holder is surrounded by two box-shaped elements, which surround the holder with a slight amount of clearance and fit one in the other and, if any, in a screening jacket of the device, each element having a coupling portion adapted to be connected with a coupling portion of the holder. It is thus possible to connect the two sides of the holder rapidly with the elements, while the second box-shaped element is slipped onto the first element like a lid.

An advantageous embodiment of the device according to the invention is characterized in that a connection between a vessel and a coupling portion adapted to be connected with a holder coupling includes a further detachable coupling member, a first portion of which is fastened to the vessel and a second portion to the coupling portion adapted to be connected with the holder. It is thus possible to handle a vessel and a box-shaped element as separate parts. They may therefore be sterilized separately, but the particular advantage of this embodiment resides in that the sterile quick connections of the holder once established need not be interrupted for the whole lifetime of the mother substance. During this period of time, in which the generator may be repeatedly washed, the box-shaped elements, if provided, remain in the device, while the vessels for the washing fluid and the product can be replaced according to need after each washing operation or more frequently.

A further connection between a quick-coupling member for the holder and a vessel may be established by means of a readily sterilizable coupling member, preferably a quick-coupling member known from the medical instrument technology. In a further advantageous embodiment the device according to the invention is characterized in that a coupling portion fastened to a vessel is formed by a pierceable wall portion of the vessel, while the coupling portion to be connected therewith is formed by a hollow needle. For withdrawing the air from the vessel a second hollow needle may be pierced through said wall portion of the vessel.

In a further advantageous device embodying the invention the vessel need not be freed of air. This embodiment is characterized in that the vessel is substantially cylindrical and accommodates a movable piston. When using such a vessel both beneath and above the holder, that is to say both for the washing fluid and for the product, the vessel and the holder of the resultant device form a closed system, into which no air need be introduced above the washing fluid and from which no air need be removed from the collecting vessel. This device approaches therefore very closely the ideal of a perfectly sterile product.

A vessel with a piston may be formed by the body of a medical syringe.

The invention will be described more fully with reference to the drawing, which shows a device according to the invention in a diagrammatic sectional view.

In the position shown the device is provided with the holder having the substance containing radioactive constituents and the vessels for the washing fluid and the product to be collected.

The holder 1 of the device may contain a radioactive mother substance, such as molybdenum-99 or germanium-68, bound to an ion exchanger, formed for example by given resins or aluminum oxide. The binder and the mother substance are designated by 2; they are provided in the holder 1 above a filter 3. The holder 1, which is cylindrical in this embodiment, may be made of glass and has an opening at the upper and the lower ends, closed by rubber plugs 4. The edges of the plugs 4 are furthermore sealed by flanged capsules 5, which leave the center of the plugs 4 uncovered.

In the position shown the holder 1 is surrounded by two box-shaped elements 6 fitting one in the other and around the holder with a small clearance. The cylindrical elements 6 are open at one end and have a prolongation 8 at the end walls 7 at the opposite ends. The ends of the prolongations 8 have a portion 9 of a mechanical quick-coupling member which by means of a screw thread is detachable. The portions 9 form at the same time the settings for the hollow needles 10, which may be soldered in said portions 9.

The vessels 11 and 12 comprise each a cylindrical body 13, for example, of glass, to which rings 14 are cemented. The lids 15 join the rings 14. The other ends of the vessels 11 and 12 are closed by lids 16. Through openings in the lids 15 emerge the piston rods 17 of the pistons 18. The lids 16 comprise the portions 19 of a mechanical quick-coupling member, which are attached in the position shown to said portions 9 of said coupling member. The vessel 11 contains a washing fluid 20, which may be a physiological salt solution.

The holder 1 and the elements 6 are largely surrounded by a screening jacket 21, for example, of lead. Through the screening jacket 21 bolts 22 are taken for clamping the elements 6 in the jacket 21. The jacket 21 is closed at the upper end by lids 23, for example, of lead. The vessel 12 for collecting the radioactive fluid is surrounded by a screening formed by a cylindrical jacket 24, cut into halves in the longitudinal direction, these halves being held in place by a tube 25, slipped around them and closed by a lid 26. The jacket 24, the tube 25 and the lid 26 may also be made of lead. The vessels 11 and 12 may be formed by conventional medical syringes of adequate capacities, for example 30 or 50 mls.

The screening jacket 21 bears on a support 27, having an upper plate 28, columns 29 and a base plate 30.

The device is operated as follows. The holder, closed by the plugs 5, is introduced into the sterilized lower elements 6, arranged previously in the jacket 21, while the lower plug is pierced by the lower needle 10. The lower coupling portion 9 may be closed by a suitable plug. The upper element 6 with its needle 10 and the coupling portion 9 is arranged in place, after which the lids 23 are arranged. The two plugs 5 of the holder 1 are then pierced by the needles 10. Also the upper coupling portion 9 may be closed by a fitting plug. The elements 6 can be fixed in place by means of the bolts 22.

Then after removal of the closing plugs from the coupling portions 9 and/or 19, if any, the vessels 12 and 11 are connected; the vessel 12 in the empty state while the piston 18 of this vessel is in the upper position and the vessel 11, filled with the washing fluid 20 beneath the piston 18 of this vessel. By force of gravitation the washing operation starts. If desired, a slight pressure may be exerted on the upper piston rod 17, for example, by means of a weight. Particularly the piston 18 of the vessel 11 has to be readily movable in the cylinder of this vessel.

The fluid 20 flows through the holder 1, while the radioactive mother substance remains bound to the binder, but the radioactive eluate is carried along downwards through the filter 3 to the collecting vessel 12.

The vessels 11 and 12 and the holder 1 form, during the washing operation, a closed system into which no air is allowed to enter and from which no air need be withdrawn. In this manner such a sterile, pyrogen-free fluid with a radioactive daughter substance is collected in the vessel 12 that subsequent sterilization is no longer required.

In the device shown, embodying the invention holders 31 with two quick-coupling portions 32 are fastened to the upper plate 28 of the stand 27. With the portions 32 may be connected for example at one end a filled vessel 12 and at the other end syringe bodies of smaller volumes to be filled in order of succession from said vessel.

The drawing shows diagrammatically only one embodiment of the invention. As a matter of course, many other embodiments of the invention differing from the construction and details of the embodiment shown are possible.

Claims

We claim:

1. A device for obtaining fluids containing radioactive constituents particularly suitable for medical purposes comprising a detachable holder closed at its upper and lower end by a pierceable wall, a pair of interfitting box-shaped members surrounding said holder, each of said box-shaped members having a prolongation which is provided with a first part of a quick-coupling means, said first part for each prolongation carrying a hollow needle which protrudes into said pierceable wall during operation of said device, a vessel for containing washing fluid having a second part of said quick-coupling means to be connected with the first part of said quick-coupling means at the upper side of the holder, and a vessel for the fluid to be collected having a second part of said quick-coupling means at the lower side of the holder.

2. A device as claimed in claim 1 in which each vessel has a substantially cylindrical shape and accommodates a moveable piston.

3. A device as claimed in claim 2, in which characterized in that the vessel for the washing fluid and the vessel for collecting the product are formed each by the body of a syringe in which a piston is adapted to move.