Patent Description:
The present disclosure relates generally to nuclear medicine and specifically concerns <NUM>Sr/<NUM>Rb elution systems.

The subject matter disclosed herein relate to radiopharmaceutical substances with short half-life, such as Rubidium (<NUM>Rb). Rubidium (<NUM>Rb) is used as a positron emission tomography (PET) tracer for non-invasive determination of myocardial perfusion (blood flow).

Typical <NUM>Sr/<NUM>Rb elution systems comprise a reservoir of sterile saline solution (e.g., <NUM>% Sodium Chloride Injection), one or more pumps to pump the sterile saline solution from reservoir, a source for generating radioactive isotopes in solution, a radioactivity detector to measure activity of different isotopes, a dose calibrator, a waste container, set of infusion tubing assembly, one or more sensors, a computer, and shielded enclosures on a platform meant to move the elution system. During operation of such systems, the pump moves the saline solution from the reservoir and through the generator to elute the <NUM>Rb which is eluted in the form of <NUM>RbCl and also to regulate the flow of sterile saline solution to the bypass line. The radioactive solution which exits the generator is then infused to a patient to be diagnosed via a patient outlet. As known among those skilled in the art, <NUM>Rb is generated by radioactive decay of the <NUM>Sr, and thus the rate of production of <NUM>Rb at any given time, is a function of the activity of <NUM>Sr remaining in the generator. The rate of <NUM>Rb production exponentially decreases through the useful life of the generator, directly in correlation with the half-life of <NUM>Sr.

The various shielded and non-shielded components in the elution system play a role in providing a desired dose, and ensuring a safe and an easy to clean environment. All known <NUM>Sr/<NUM>Rb generator systems like Cardiogen-<NUM>® and RUBY-FILL® have a waste container that is on top of their respective structures, and at a higher elevation relative to the generator and/or the pump. The present inventors have identified alternate configurations of elution system that offer several advantages.

<CIT> describes an infusion system which may include a strontium-rubidium radioisotope generator that generates a radioactive eluate via elution, a beta detector, a gamma detector, and a controller. The beta detector and the gamma detector may be positioned to measure beta emissions and gamma emissions, respectively, emitted from the radioactive eluate. In some examples, the controller is configured to determine an activity of rubidium in the radioactive eluate based on the beta emissions measured by the beta detector and determine an activity of strontium in the radioactive eluate based on the gamma emissions measured by the gamma detector.

<CIT> describes a means of automation of the process of generating a diagnostic solution from a radionuclide strontium-rubidium generator and performing of remote controlled infusion, with automatic control over the key characteristics of the process. The automated strontium-rubidium infusion system comprises a container with eluent, a strontium-rubidium generator with a filter and a pressure sensor at the input, an eluate infusion unit, which are connected by means of a transporting system provided with pipes and two three-way valves, radioactivity measuring means and a control and operating unit. Here, an eluent container is connected to a syringe pump via the first and second ports of the first three-way valve, the first port of the second three-way valve is connected with pipes via the second filter to the eluate infusion unit, and the second port is connected to a waste receptacle. The system additionally comprises the third and fourth three-way valves, the first and second air bubbles detectors are connected to the control and operating unit connected with a computer, where the third three-way valve is connected with its first and second ports via pipes to the third port of the first three-way valve and the input of the strontium-rubidium generator, respectively. The generator output is connected to the first port of the fourth three-way valve, where the third port of the third valve and the second port of the fourth valve are connected with a pipe, the first air bubbles detector is placed on the pipeline between the eluent container and the first port of the first valve, and the second air bubbles detector is placed on the pipeline between the third ports of the fourth and second valves.

An object of the present disclosure is to provide new configurations of a rubidium elution system wherein the waste container is located in a lower section of an assembly that contains the various components of the system, such as at a lower elevation than the pump, at the same elevation than the generator, or at an elevation where the top surface of the compartment housing the waste container is lower than the elevation of the top surface of the compartment housing the generator. Another object of the disclosure is to provide safety means that are adapted to these new configurations of a rubidium elution system.

Another object of the present disclosure is to provide a method for manufacturing said new configurations of rubidium elution system.

Other objects, advantages and features of the present disclosure will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of examples only with reference to the accompanying drawings.

As used herein, the terms "elution system", "rubidium elution system" and "<NUM>Sr/<NUM>Rb elution system" can be used interchangeably and refer to a strontium-rubidium infusion system for use in generating a radioactive solution containing rubidium-<NUM>, measuring the radioactivity in the solution generated by the system, and infusing the radioactive solution to a patient in order to perform various studies on a patient's organ, such as heart or kidney.

As used herein, the terms "cart" or "system" or "trolley" are intended to encompass a platform. Said platform can be mobile or stationary.

The material used for "shielding" is made up of any radiation attenuating material, including, but not limited to, depleted uranium (U), lead (Pb), tin (Sn), antimony (Sb), tungsten (W), bismuth (Bi), any other material, or any combination thereof, as long as it provides a barrier to the radioactivity of rubidium or strontium.

As used herein, the term "shielded component" refers to components of the system that are surrounded by a shielding material, and may refer to the generator, the dose calibrator, the activity detector, the waste container, and/or the tubing line or a part of the tubing line.

As used herein, the term "non-shielded components" refers to components of the system that are not shielded, such as the pump, the valves, the saline reservoir, the computer, the controller of the system, the interface of the dose calibrator, and/or the tubing line or a part of the tubing line.

As used herein, the term "cabinet structure" refers to an outer structure of the system that extend upward from a platform and houses an assembly. The cabinet structure may be formed of any radiation resistant material, including, but not limited to, stainless steel, injection-molded polyurethane, or any other suitable materials or combination thereof.

As used herein, the term "supporting accessories" refers to items such as wheels, lever, paddle, additional saline reservoir, drawer system for housing vials, and a handle for facilitating movement of the system.

As used herein, the expression "locking means for preventing access to the interface by a user of the system" refers to any mechanism, system, or technology to provide security against access by a user to the interface, such as a locked compartment enclosing the interface of the dose calibrator, the requirement for input of a security code or security data (RFID, biometric, numeric, audible, or the like) for modifying the parameters of the interface, integrating the interface into the dose calibrator in such a way that the interface is rendered not accessible, or the like. In an embodiment, only the manufacturer have access to the interface of the dose calibrator. In another embodiment, no one has access to the interface. Being placed outside the primary assembly, the dose calibrator is therefore accessible and it is advantageous to prevent a user from modifying the interface parameters in order to ensure that the dose calibrator remains set properly for the rubidium elution system of the present disclosure.

The generator column may be prepared in accordance with <CIT>.

The generator system should be able to perform all the desired functions without unwanted and hazardous effects. <NUM>Rb has a half-life of <NUM> seconds, and its potential impurities, <NUM>Sr and <NUM>Sr, have a half-life of <NUM> days and <NUM> days, respectively. It is essential that patients are not exposed to these undesired isotopes, of which both are characterized by a long half-life. Accordingly, in order to ensure adequate safety, quality control testing of the generator is performed on daily basis prior to use. The daily quality control process for the generator includes collecting an eluted sample in a shielded vial for evaluation, and measuring the activity of the sample in a dose calibrator. Further, the sample is retained to permit decay of all active rubidium, after which a second stage of breakthrough testing is performed. The measured initial activity and the final activity are used to calculate the breakthrough information. The United States Pharmacopeia (USP) provides relevant regulatory limits for breakthrough of strontium of <NUM>µCi of <NUM>Sr/ mCi of <NUM>Rb activity and <NUM>µCi of <NUM>Sr/ mCi of <NUM>Rb activity. Further, to ensure a higher degree of safety, a system may impose a more stringent limit of <NUM>% of the USP limits.

A constant activity-rate refers to an activity-rate delivered with respect to time wherein the activity-rate is constant with respect to a predetermined constant activity concentration. A method to deliver a constant activity-rate dose is described in <CIT>.

Different elution strategies that can be used for patient infusions include:.

In the embodiments, the rubidium elution system includes a controller configured to control the pump and the at least one valve so as to deliver a solution of rubidium at a constant activity rate to a patient.

<FIG> is a front view of a rubidium elution system <NUM> of the present disclosure where the assembly <NUM> is enclosed into a cabinet structure <NUM>. The cabinet structure <NUM> has a front door <NUM> that gives access to the waste compartment <NUM> housing the waste container <NUM> and access to the generator compartment <NUM> housing the generator <NUM> (not shown) that is housed in a generator compartment <NUM>. In the embodiment shown in <FIG>, the waste compartment <NUM> has a waste door <NUM> that provides access to the waste container <NUM>. Preferably, the waste container <NUM> is housed within an enclosure <NUM> that may be removed from its shielded compartment <NUM> when the waste door <NUM> is opened, as shown in <FIG>. In a certain embodiment, the waste container <NUM> can be accessed from the waste container compartment <NUM> horizontally by mounting a waste platform on rails. In this embodiment, the waste platform is slid out horizontally prior to pulling out the waste container <NUM> from its compartment (sliding out mechanism). In another compartment, the waste container <NUM> is removed by a lifting mechanism that can be automated. In the embodiment of <FIG>, the dose calibrator <NUM> can be accessed by opening a top panel <NUM> of the cabinet structure <NUM>.

<FIG> provides a front view of an embodiment of the rubidium elution system <NUM> according to the present disclosure, where the assembly <NUM> is positioned on a platform <NUM> (shown in <FIG>) that is mobile. In this embodiment, mobility is provided by means of wheels <NUM>, and it can be manually or motor driven. As it can be seen in <FIG> and <FIG>, the assembly <NUM> and the platform <NUM> are preferably recovered by a cabinet structure <NUM>. The platform <NUM> preferably includes two pairs of wheels <NUM> mounted on a bottom side of the platform, for allowing the mobility of the elution system <NUM>. In some embodiments, the platform <NUM> includes a mechanism for braking and locking the wheels <NUM>, such as a lever.

In an embodiment as the one shown in <FIG>, the rubidium elution system further comprises a computer screen <NUM> for displaying the information about the rubidium elution and the patient infusion. Preferably, the screen <NUM> is a touch screen where the user may provide inputs to the computer (not shown) about patient information and on the desired dose of rubidium. The computer is preferably integrated into the assembly <NUM>.

Preferably, the waste door <NUM> of the waste compartment <NUM> has an upper edge and lower edge, the upper edge of the waste door <NUM> is located at a lower elevation than the elevation of the opening <NUM> of the generator compartment <NUM>. In an embodiment, the elevation of the upper edge of the waste door <NUM> is from about <NUM> to about <NUM> (<NUM> inches to about <NUM> inches) above the platform <NUM>, more preferably from about : <NUM> to about <NUM> (<NUM> to about <NUM> inches) above the platform <NUM>, and further preferably at <NUM> ± <NUM> (<NUM> ± <NUM> inches ) above the platform <NUM>, or further preferably at <NUM> ± <NUM> (<NUM> ± <NUM> inches) above the platform <NUM>, or further preferably at <NUM> ± <NUM> (<NUM> ± <NUM> inches) above the platform <NUM>. In another embodiment, the lower edge of the waste door <NUM> is from about <NUM> inches to about <NUM> (<NUM> inches) above the platform <NUM>. The <NUM> is defined with an upper section and a lower section. According to the present disclosure, the waste container <NUM> is located in the lower section of the assembly <NUM>. In an embodiment, the lower section represents the lower two third of the assembly <NUM>. In another embodiment, the lower section represents the lower half of the assembly <NUM>. Positioning the waste container <NUM> in the lower section of the assembly <NUM> offers several advantages for the user and for the system, such as distancing the waste container from the user's eyes, lowering the center of gravity that provides higher stability of the system, making it easier to clean and decontaminate in case of a spilling or overflow, and easier to replace the waste container, and preventing any waste overflow to run through electronic components that may result in shorting-out the system. It also leaves additional space for the pump <NUM> that is usually located on the upper portion of the assembly <NUM>. More particularly, the new configurations allow the pump <NUM> to be horizontally oriented, as illustrated in <FIG>. Advantageously, horizontal orientation is the typical orientation of the peristaltic pump, and is recommended by the manufacturer.

In certain aspects, the term "about" preferably refers to <NUM>% of the corresponding value. In other aspects, the term "about" preferably refers to <NUM>% of the corresponding value.

According to certain preferred embodiments, the top surface of the waste compartment <NUM> is at a first elevation; and the top surface of the generator compartment <NUM> is at a second elevation; and the first elevation is lower than the second elevation.

According to the invention, the waste compartment <NUM> and the generator compartment <NUM> are at the same elevation.

According to the invention, the waste container <NUM> is at an elevation, which is lower than the pump <NUM>.

In the presently disclosed rubidium elution systems, when emptying the waste container <NUM> is necessary, the user may i) open the door <NUM> of the cabinet structure, ii) open the door <NUM> of the waste compartment <NUM>, iii) pull horizontally the enclosure <NUM>, iv) disconnect the waste line (not shown) attached thereto, and v) lift the waste container <NUM> so as to remove it from its enclosure <NUM>.

In certain embodiments, the <NUM>Sr/<NUM>Rb generator, the dose calibrator, the waste container, and the activity detector are enclosed within respective shielded compartments. Preferably, each of the <NUM>Sr/<NUM>Rb generator, the dose calibrator, the waste container, and the activity detector is enclosed within a respective shielded compartments. The door <NUM> of the waste compartment <NUM> is preferably shielded. The opening of the generator is also preferably shielded.

<FIG> shows a front view of a rubidium elution system according to the present disclosure. The tubing circuit includes an eluant line <NUM> that provides an eluant (preferably a saline solution contained in a saline reservoir <NUM>) to the generator <NUM> by means of a pump <NUM>. The tubing circuit also includes a bypass line <NUM> connected to the eluant line <NUM> that carries the eluant to the tubing circuit downstream the generator <NUM> such that the eluant bypasses the generator <NUM>. The tubing circuit further includes a waste line <NUM> that directs into a waste container <NUM> a mixture composed of the eluant fed by the bypass line <NUM> and the radioactive eluate that has exited the generator <NUM>. The tubing circuit also further includes a patient line <NUM> that directs the same mixture to either i) a patient for infusing said patient with a rubidium solution, or ii) a vial located in the dose calibrator <NUM> for system's calibration and strontium breakthrough test. The activity detector <NUM> can be a beta detector, a positron detector, or a beta and positron detector. In the embodiments, the rubidium elution system <NUM> comprises at least one valve <NUM>. Preferably, said at least one valve <NUM> comprises a valve upstream the generator <NUM> and a valve downstream the generator <NUM>. Said valves <NUM> can be embodied by pinch valves and/or divergence valves.

In certain embodiments, the pump <NUM> that can be embodied by a syringe pump, a peristaltic pump, or another type of pump. In the embodiment of the present invention shown in <FIG>, the pump <NUM> is a peristaltic pump and is mounted horizontally on the front panel of the assembly <NUM>. The expression "horizontally mounted" or "horizontally oriented" means that the motor and the pump component of the pump assembly <NUM> are at the same elevation. The pump <NUM> is preferably located from about <NUM> to about <NUM> (<NUM> inches to about <NUM> inches) above the platform <NUM>.

According to the invention, the dose calibrator is accompanied with its own interface that configures the dose calibrator for detection of rubidium. The system further includes a locking means for preventing a user from reconfiguring the dose calibrator in such a way that the dose calibrator remains configured as initially configured by the manufacturer. In a preferred embodiment, the dose calibrator is configured to detect rubidium and/or strontium. In a further preferred embodiment, the dose calibrator is configured to detect rubidium. Since strontium and rubidium are in an instant equilibrium, one can use the measured quantity of rubidium to calculate the quantity of strontium that is present in a solution after the initial content in rubidium has decayed. One a way to prevent a user from reconfiguring the dose calibrator is to prevent access to the interface of the dose calibrator. In an embodiment, the locking means comprises an identification system for allowing access to the interface and reconfiguring the dose calibrator by the manufacturer of the system and not the user of the system. In another embodiment, the locking means comprises a locked compartment <NUM> as shown in <FIG> and <NUM>, which encloses the interface of the dose calibrator <NUM> and prevents access to by the user of the system. Preferably, the manufacturer of the system remains able to unlock the compartment of the interface and able to configure or reconfigure the dose calibrator as needed. In a variant of this embodiment, the locked compartment enclosing the interface of the dose calibrator <NUM> is provided by a second cabinet structure <NUM> that also encloses or partly encloses the dose calibrator <NUM>. The compartment enclosing the interface can be included in the cabinet structure. In another embodiment the interface is integrated in the dose calibrator and not accessible to the user.

In certain aspects, the computer of the rubidium elution system is configured to proceed with a quality control test (breakthrough tests) at pre-determined time, upon user's request and at least once a day. The computer is configured to prevent a patient infusion when the quality control test result determines that the strontium concentration is equal to or above <NUM>µCi of <NUM>Sr/ mCi of <NUM>Rb activity or equal to or above <NUM>µCi of <NUM>Sr/ mCi of <NUM>Rb activity.

In other aspects, the rubidium elution system comprises a computer screen includes a speaker for providing an audible or visible alert for one or more different operations of system.

In certain embodiments, the rubidium elution system comprises a computer having a processor and a memory communicatively connected to the processor when the system is functioning. Memory has processor-executable instructions that, when executed on the processor, cause the system to perform representative functions of the system.

Claim 1:
A rubidium elution system (<NUM>) comprising an assembly (<NUM>) that includes a <NUM>Sr/<NUM>Rb generator (<NUM>), an activity detector (<NUM>), a waste container (<NUM>), a pump (<NUM>), a sensor, a tubing circuit, at least one valve (<NUM>); and a computer, wherein:
- the assembly has a lower section and an upper section, wherein the lower section consists of the lower half of the assembly, and
- the waste container is located in the lower section of the assembly;
- the waste container is enclosed in a waste compartment (<NUM>);
- the generator is enclosed in a generator compartment (<NUM>);
- the waste compartment is at an elevation within the assembly that is the same as an elevation at which the generator compartment is located;
- the waste container is at an elevation that is lower than the pump;
- the assembly further comprises a dose calibrator (<NUM>) that is configured to detect at least one radioisotope;
- the rubidium elution system further comprises locking means for preventing a user of the system from changing a configuration of the dose calibrator, wherein the dose calibrator further comprises an interface for configuring the dose calibrator, and wherein the locking means prevents a user from changing a configuration of the dose calibrator by locking the interface;
- the rubidium elution system includes a sliding mechanism or a lifting mechanism for removing the waste container from the waste compartment.