Abstract:
A container for a polarizable gas includes an elongate container sheet having a laminate of a sealing layer and a barrier layer, a sealed container cavity defined by the container sheet by perimetrically sealing the sealing layer upon itself so as to enclose the container cavity, and a quantity of a polarizable gas within the container cavity. A method of evacuating the polarzable gas from the container includes evacuating the passageway of a fitting attached to the container prior to puncturing the container and evacuating its contents through the fitting.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to the field of the storage containers. More specifically, the present invention is directed to a storage and delivery container for a polarizable gas.  
         BACKGROUND OF THE INVENTION  
         [0002]    The use of hyperpolarized gases for ex-vivo and in-vivo imaging is well known. As models for the widespread distribution of hyperpolarized gas doses become better defined, it is clear that a system providing for point-of-use polarization of gases be developed. In order to decrease the risk of waste, it is desirable to provide a unit-dose container for a polarizable gas which may be delivered to an imaging center and used on a per-patient basis. Moreover, a method for dispensing the contents of the container must ensure the gas contents do not become contaminated with ambient air.  
           [0003]    The present invention addresses the need in the art for a unit-dose container for a hyperpolarizable gas which maintains the integrity of a dose through both storage and discharge.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention addresses the needs of the art by providing a container for a polarizable gas formed from an elongate container sheet having a laminate of a sealing layer and a barrier layer. A sealed container cavity is defined by the container sheet by perimetrically sealing the sealing layer upon itself so as to enclose the container cavity. A quantity of a polarizable gas is provided within the container cavity.  
           [0005]    The containers of the present invention are contemplated to provide a unit dose of a polarizable gas useful for hyperpolarized gas imaging and spectroscopic applications as is known with conventional magnetic resonance imaging (MRI) equipment. The containers desirably enclose approximately 0.5 liters of a gas at atmospheric pressure with sufficient capacity to accommodate thermal expansion of the gas without causing the container to rupture.  
           [0006]    The containers are formed from a multilaminate barrier sheet material for maximizing shelf-life. The barrier sheets desirably include a layer for providing scratch resistance to the container, a metallic layer for preventing permeation of the gas from the container, and a layer for allowing easy sealing of the container.  
           [0007]    The containers of the present invention may further include a connector fitting affixed to the barrier material for interfacing with a gas extraction device. The connector fitting defines an elongate fitting passageway through which the gas contents of the container may be evacuated. The connector fittings desirably do not penetrate the metallic layer of the multilaminate barrier sheet material so as not to degrade the blocking characteristics of the material. The connector is desirably bonded or heat-sealed to the outside of the container during manufacturing. Puncture of the container for extraction of the gas contents may be accomplished through the connector fitting.  
           [0008]    The containers of the present invention may be attached to an evacuation device which engages the connector fitting in a fluid-tight manner. The fitting passageway is first evacuated of any contaminating gases prior to puncturing the container and evacuating the gas contents through the fitting passageway. Desirably, the container is punctured through the fitting passageway. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 depicts a first container of the present invention.  
         [0010]    [0010]FIGS. 2A and 2B depict alternate multilaminate barriers of the containers of the present invention.  
         [0011]    FIGS.  3 - 4  depict another container of the present invention.  
         [0012]    [0012]FIG. 5 depicts yet another container of the present invention.  
         [0013]    [0013]FIG. 6 depicts still another container of the present invention.  
         [0014]    [0014]FIG. 7 depicts a gas loading system adapted for the container of FIG. 5.  
         [0015]    [0015]FIG. 8 depicts still yet another container of the present invention.  
         [0016]    [0016]FIG. 9 depicts a gas loading system adapted for the container of FIG. 7. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    As shown in FIG. 1, the present invention provides a container  10  for storing and delivering a mixture having a polarizable gas such as 3He or 129Xe. The container is generally a bag or soft container and is desirably formed from any material suitable for the purpose of storing the gas prior to its polarization. Container  10  is scalable so as to hold any size of a pre-selected dose of the polarizable gas. Each dose of the polarizable gas is contemplated to include some amount of another gas, such as N 2 . For example, by way of illustration and not of limitation, each container of the present invention may hold a 0.5 liter gas mixture which comprises 99.25% 3He and 0.75% N 2 .  
         [0018]    Container  10  is desirably formed by a single elongate sheet  12  of container material and, optionally, an attached fitting  14 . Container sheet  12  is folded about a transversely-extending crease area  16  so that the overlapping perimetrical edges of sheet  12  may be welded together to form a partial perimetrical seam  18  extending between opposed ends  16   a  and  16   b  of crease area  16 . Container sheet  12  thereby defines an enclosed container cavity  20  for storing a dose of polarizable gas. The present invention contemplates that Fitting  14  may be adhered or bonded to an outside surface  12   a  of container  10  so as to provide an adaptor for establishing fluid communication between cavity  20  and the polarization region of a polarizer device, not shown. The present invention further contemplates that container  10  may be formed from a fully perimetrical weld of a first and second container sheet  12  positioned in facing opposition so as to form enclosed cavity  20 .  
         [0019]    As shown in FIG. 2A, sheet  12  is desirably formed from a multilayer laminate made from, as viewed from cavity  20  to outside surface  12   a , at least a sheet of polyethylene  13  and a sheet of aluminum foil  15 . The present invention further contemplates including layers of polyester and PET in constituting sheet  12 . A polyethylene is desirably provided to form the interior layer of container  10  so as to ensure sealing of cavity  20  by perimetrical seam  18 . The aluminum layer is contemplated to act as a barrier for the hyperpolarizable gas. It is further contemplated to metalize a polyethylene or polyester layer so as to provide for both heat sealing and gas barrier. With additional reference to FIG. 2B, another polyester layer  19 , such as polyvinylidene chloride, is further contemplated for providing improved tear or puncture resistance. A PET layer  13  is contemplated to provide improved scratch or abrasion resistance. The present invention further contemplates alternate combinations of the order and location of the laminated layers may be provided to form sheet  12 .  
         [0020]    Fitting  14  is desirably formed from a suitable plastic material and includes an elongate cylindrical wall  22  defining an elongate passageway  24  extending between opposed wall ends  26  and  28 . Fitting  14  desirably includes an annular flange  30  extending about second end  28  of cylindrical wall  22  so as to provide a larger surface area for bonding to outside surface  12   a  of container sheet  12 . Annular flange  30  may either define a central opening exposing surface  12   a  to passageway  24  or may be a solid member which further isolates passagway  24  from surface  12   a . The means for affixing fitting  14  to sheet  12  desirably does not penetrate the aluminum layer  15  so as to minimize permeation of the stored gas therepast. It is contemplated that cylindrical wall  22  may be formed with luer-lock means extending either outwardly therefrom or inwardly into passageway  24  for engaging a complimentary fitting on a polarizer. Outwardly-projecting lugs  25  and  27  may be employed for this purpose. The polarizer into which the gas contents are delivered is equipped with the ability to first evacuate passageway  24  and then both puncture container  10  and evacuate cavity  20 . In embodiments of the present invention lacking the attached fitting  14 , the present invention contemplates that the polarizer will incorporate the means for providing a fluid-tight and evacuated attachment to fitting  14  as well as the means to puncture container sheet  12  and evacuate cavity  20 .  
         [0021]    Additional steps in the construction and filling of container  10  will be apparent from the descriptions hereinbelow.  
         [0022]    [0022]FIGS. 3 and 4 depict a second container  110  of the present invention. Container  110  is desirably formed from a single elongate container sheet  112  and, optionally, a fitting  114 . Container sheet  112  and fitting  114  are similar to sheet  12  and fitting  14  as previously described whereby like numbering describes like features. Container sheet  112  is folded about a crease  116  and the overlying edges are welded together so as to form a partial perimetrical seam  118  bounded by crease  116 . Sheet  112  thereby provides a container cavity  120  for storing a dose of polarizable gas.  
         [0023]    As shown in FIG. 4, container sheet  112  and seam  118  form an open inlet port  125  defining an inlet passagway  130  in fluid communication with cavity  120 . The polarizable gas is introduced into cavity  120  through passageway  130 . The present invention contemplates that a fluid-tight seal may be established between a filling device, not shown, and container  110  at inlet port  125 . Container  110  will undergo at least one cycle of receiving a purge gas, such as N 2 , through passageway  130  followed by a vacuum extraction of the contents of cavity  120  through passageway  130 . It is desirable to evacuate all of the oxygen and other gases which may be entrapped in cavity  120  during the fabrication process. After undergoing the desired number of purge/vacuum cycles, the filling device will then deliver the polarizable gas through passageway  130  into cavity  120 . While maintaining a fluid tight engagement about inlet port  125 , seam  118  is completed across passageway  130  so as to isolate cavity  120  from the outside environment.  
         [0024]    [0024]FIG. 5 depicts yet another container  210  of the present invention. Container  210  is formed from a container sheet  212  and, optionally, a closed fitting  214 . Container sheet  212  is similar to sheet  12  as previously described whereby like numbering describes like features. Container sheet  212  is folded about a crease  216  such that overlying edges thereof may be welded together to form a partial perimetrical seam  218  and thereby define an enclosed container cavity  220 . Cavity  220  is sized to contain a dose of polarizable gas for use in an imaging or spectrographic procedure. Seam  218  may be formed having a large enough surface area to accommodate various markers or indicia such as lables or bar codes. Container  210  is desirably formed having an inlet port  225  defining a passageway  230  in fluid communication with container cavity  220 .  
         [0025]    Container  210  is further shown incorporating sealed fitting  214  into seam  218 . Sealed fitting  214  defines an elongate cylindrical fitting passageway  224  exteding in fluid communication with open end  226  thereof. Passageway  224  is in obstructed fluid communication with cavity  220 . The present invention further contemplates affixing an adaptor, such as fitting  14 , to the outside surface  212   a  of container  210 . It is also contemplated that passageway  224  will be evacuated of any contaminating gases prior to puncturing the closed end of fitting  214 . Sealed fitting  214  may be punctured so as to render the contents of cavity  210  accessible for evacuation into a polarizer.  
         [0026]    [0026]FIG. 6 depicts a dual-dose container  310  of the present invention. A dual-dose container is intended to provide enough polarizable gas for performing a full imaging or spectrometry procedure for a patient. Container  310  is desirably formed by perimetrically and transversely welding a first and second container sheet  312  and  312 ′ together. Perimetrical seam  318  and transverse seam  319  define first and second enclosed cavities  320  and  320 ′ therebetween. Cavities  320  and  320 ′ are each sized to contain a single dose of a polarizable gas. Container  310  is shown as providing first and second open inlet ports  325  and  325 ′ as interruptions in seam  318  so as to define first and second passageways in fluid communication with first and second cavities  320  and  320 ′, respectively. Once cavities  320  and  320 ′ have been evacuated and filled an appropriate number of times to ensure contaminant gases have been removed therefrom, the polarizable gas may be delivered thereto through ports  325  and  325 ′, respectively. Then, prior to fully disengaging the filling device from the container, seam  318  may be completed so as to isolate ports  325  and  325 ′, thereby rendering cavities  320  and  320 ′ closed. Seam  318  also incorporates elongate fittings  314  and  314 ′, which are similar to fitting  214  in design and operation.  
         [0027]    [0027]FIG. 8 shows a gas loading system  500  for filling dual-dose container  310 . Gas loading system  500  includes a cannister supply  501  of N 2  and a hyperpolarizable gas. Gas loading system  500  further includes first and second gas injector probes  502  and  504  receivable in inlet ports  325  and  325 ′, respectively. Gas loading system further includes means for maintaining a fluid tight connection between probes  502  and  504  and inlet ports  325  and  325 ′ while performing both the purge and evacuation cycles and the sealing of the inlet ports after filling cavities  320  and  320 ′ with the polarizable gas.  
         [0028]    [0028]FIG. 9 depicts a unit-dose cylinder  610  of the present invention. Cylinder  610  provides a rigid container for transporting a hyperpolarizable gas. The contents of cylinder  610  may be dispensed into a flexible gas container of the present invention. Cylinder  610  is desirably formed from aluminum or stainless steel. Cylinder  610  includes an outer container wall  612  having an open end  614  covered by a puncturable cover  615 . Container wall  612  defines and interior cavity  616 , in fluid communication with open end  614 . Open end  614  may further include therein a poppet-type or ball-type valve for controlling the introduction and evacuation of gases into and out from cavity  616 . It is further contemplated that container wall  612  is annularly scored or weakened about open end  614  where cylinder  610  may be opened.  
         [0029]    [0029]FIG. 8 depicts a gas loading system  700  adapted for filling a unit-dose container of the present invention. Gas loading system  700  includes a rotary turntable  702  for accommodating a number of unit-dose cylinders  610  thereon. Turntable  702  positions each end  614  of cylinder  610  in underlying spaced registry below an extraction nozzle  704 . Extraction nozzle  704  may be extended into sealed contact about end  614  of a cylinder  610  and includes the means to purge the void extending between the openable end of the cylinder and a gas delivery valve within fill nozzle  704 . Fill nozzle  704  includes the means for purging oxygen from the void prior to communicating with cavity  616  and extracting the polarizable gas mixture therefrom. The polarizable gas mixture may include, for purposes of illustration and not of limitation, a polarizable gas and N 2 . Gas loading system  700  also includes means for filling a flexible container of the present invention as previously described.  
         [0030]    While the particular embodiment of the present invention has been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the teachings of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.