in this specification and claims , numerical values and ranges are not critical unless otherwise stated . that is , the numerical values and ranges may be read as if they were prefaced with the word “ about ” or “ substantially ”. referring first to fig1 a manifold assembly 11 has a housing 13 having a front portion 15 and a rear portion 17 . extending through the face of the front portion 15 are pressure knob 21 and fluid knob 23 . surrounding inlet knob 21 and fluid knob 23 are indica 25 to inform the user of the relative position of the knobs . when in an upright position , manifold assembly 11 rests on its bottom surface 27 . at the top of manifold assembly 11 is a pressure port 31 , which is illustratively a luer connection of the type commonly found on medical equipment such as syringes . in fig2 the inside of front portion 15 of manifold assembly 11 is shown . the major parts of front portion 15 include an outer shell 33 , and inner shell 35 and a lead shield 37 which fits between outer shell 33 and inner shell 35 . additional lead shielding is present at top shield 41 and bottom shield 43 . also visible inside front portion 15 are the insides of pressure knob 21 and fluid knob 23 . the inside face of pressure knob 21 has groves 22 and the inside face of fluid knob 23 has groves 24 , which correspond to valve handles ( described below ). ratchet 45 pivots on a central pin 46 and is rotated by spring 47 so that pawl 48 engages gaps 49 spaced along the outer periphery of fluid knob 23 , permitting fluid knob 23 to be rotated in only one direction ( clockwise , as viewed from the perspective of fig1 .). the bottom surface 27 of front portion 15 is open to receive a vial seated in a container shield ( both described below ). pins 51 engage gaps on the container shield to retain it in place ( described below ). grommet 53 is attached to inner shell 35 . referring now to fig3 rear portion 17 of manifold assembly 11 is shown . the major parts of rear portion 17 include an outer shell 33 a , and inner shell 35 a and a lead shield 37 a which fits between outer shell 33 a and inner shell 35 a . additional lead shielding is present at top shield 41 a and bottom shield 43 a . pins 51 a are identical to those shown in fig2 . a manifold 55 has a manifold tube 57 having a circular cross section . a plug 59 is slidably received in the interior of tube 57 . manifold tube 57 rests in an inner shield 81 made from a plastic block 83 and lead strips 85 . a half grommet 53 a , along with half grommet 53 ( fig2 ) supports manifold tube 57 . a pressure path 61 is defined by a pressure tube 63 which terminates at pressure port 31 . pressure tube 63 is curved and passes through an opening defined by top shields 41 and 41 a in order to limit the amount of radiation that is able to exit near the top of manifold assembly 11 . pressure valve 65 connects the upper end of manifold tube 57 to pressure tube 63 . pressure valve 65 has a handle 66 which mates with groves 22 of pressure knob 21 ( fig2 ). a fluid valve 67 has a handle 68 which mates with groves 24 of fluid knob 23 . fluid valve 67 connects the lower end of manifold tube 57 to inlet path 69 and outlet path 71 . inlet path 69 , as illustrated , is a direct connection of hollow needle 73 by means of a luer connection 75 . a binding ring 87 , tightened by a screw 89 , prevents needle 73 from being pushed vertically upward into housing 13 . outlet path 71 is an outlet tube 77 that allows fluid valve 67 to communicate with outlet port 79 . turning now to fig4 and 5 , a container shield 101 has a hollow cylindrical outer shell 103 that mates with an inner shell 105 . a lead shield 121 is sandwiched between outer shell 103 and inner shell 105 , and a resilient pad 123 lies at the bottom of inner shell 105 . a rubber grommet 117 lies in a groove 119 at the top of inner shell 105 . outer shell 103 is connected to a base 107 which include a resilient sub - base 109 . four locking flanges 111 are evenly spaced around the outside of hollow cylindrical portion 103 . each locking flange 111 defines a locking detent 113 . the underside 115 of each locking flange 111 is angled to be closer to base 107 near locking detent 113 and farther from base 107 away from locking detent 113 . fig7 shows container shield 101 in locking relationship with rear portion 17 of housing 13 . to effect the locking relationship shown in fig7 a glass vial 131 is inserted into container shield 101 where it rests on resilient pad 123 . with container shield 101 sitting on a firm surface , housing 13 is lowered onto container shield 101 , so that needle 73 punctures the rubber seal 133 which is held in place with metal cap 133 and grommet 117 will contact a portion of inner shell 35 and 35 a , forming a liquid - tight seal . housing 13 is then rotated about its longitudinal axis , so that pins 51 and 51 a are pushed slightly downward by the underside 115 of locking flange 111 , until they are directly under locking detent 113 , where they move to lock container shield 101 to housing 13 . when this locking relationship exists , the tip of needle 73 is at the bottom of vial 131 so as to be able to withdraw essentially all of the liquid in vial 131 . pressure port 31 is connected to a means of providing fluid pressure ( preferably a gas such as air ) at pressures of about 0 . 1 to 0 . 4 mpa . although a simple syringe could be used , preferred is a screw syringe of the type commonly used for angioplasty . a model 2030 syringe made by acs is an exemplary source of pressure . the pressure source also preferably includes a means for at least one of measuring the pressure , measuring the duration of a treatment , warning of a pressure exceeding a preset limit , or warning of a sudden los of pressure ( which would indicate a leak in the system ). outlet port 79 is connected to a radiation treatment balloon , which may be specially made for this application , or may be an ordinary balloon catheter of the type commonly used for angioplasty . the manifold is designed such that it can be operated a number of different ways . however , the following method is believed to be optimal . to begin , pressure valve 65 is closed and fluid valve 67 is positioned to connect outlet path 71 and manifold tube 57 . fig6 shows a schematic representation of the manifold system of the invention . manifold tube 657 is connected at one end to pressure path 661 via pressure valve 665 and at the other end to vial 698 and outlet port 679 via fluid valve 667 . outlet port 679 connects to the treatment balloon 697 , passing through vacuum valve 696 which also connects to vacuum source 695 . adjacent to valves 665 , 667 , and 696 are schematic diagrams of the positions of the valves for various operating conditions . a human patient with a stenosed coronary artery was prepared for angioplasty by making an incision in the femoral artery . with the assistance of a fluoroscope , a guide wire was positioned past the stenosed region . a balloon catheter was fed onto the guide wire and advanced to the site of the stenosis . diluted hexabrix ® x - ray contrast media ( from mallinckrodt medical , inc .) is forced out of an inflator syringe by hand to inflate the balloon to 1 . 5 mpa , opening the artery . the balloon was then deflated and the catheter withdrawn from the patient . the radiation treatment procedure began with a device generally as described above , with vial 698 connected to fluid valve 667 , pressure valve 665 in position c , fluid valve 667 in position 1 , vacuum valve 696 in position a , and the manifold assembly 11 in an upright position . treatment balloon 697 was inspected , tested , connected to the manifold assembly 11 via vacuum valve 696 , and inserted into the patient . vacuum source 695 ( a vacuum syringe ) was activated and a vacuum drawn in treatment balloon 697 and manifold tube 657 . vacuum valve 696 was then turned to position b and the vacuum source 695 disconnected ( the vacuum source will not be used further in a normal procedure , but may be used for emergency removal of radioactive fluid from the treatment balloon 697 in the event of failure of other components of the system ). fluid valve 667 was then turned to position 2 . the vacuum in the system caused the radioactive fluid in vial 698 to be drawn into manifold tube 657 . after waiting a moment to ensure that all fluid movement has stopped , fluid valve 667 was then turned to position 3 . this caused some of the radioactive fluid to move into treatment balloon 697 . fluid valve 667 was then turned to position 1 , disconnecting the vial from the system . pressure source 699 ( a screw - type syringe as described above ) was attached to the system via pressure path 661 and pressure valve 665 . pressure valve 665 was then turned to position o . as pressure was applied by pressure source 699 , treatment balloon 697 inflated , dosing the artery with radiation . because the treatment blocked blood flow to the patient &# 39 ; s heart , the treatment was interrupted to allow blood flow by reversing pressure source 699 , deflating treatment balloon 697 . after a few minutes , the treatment was resumed by again activating pressure source 699 to reinflate treatment balloon 697 . when the treatment was complete , pressure source 699 was again reversed and treatment balloon 697 deflated . fluid valve 667 was turned to position 2 and pressure source 699 activated to force the radioactive fluid from manifold tube 657 into vial 698 . to ensure complete removal of the radioactive fluid from treatment balloon 697 , fluid valve 667 was turned to position 1 , pressure source 699 was reversed , fluid valve 667 was turned to position 2 , and pressure source 699 activated . finally , fluid valve 667 was turned to position 1 and pressure valve 665 turned to position c . treatment balloon 697 was then be withdrawn from the patient and the system disposed of in a manner consistent with the amount of radiation present . the procedure of example i was repeated , except that plug 59 in manifold tube 63 is porous rather than solid . by “ porous ” is meant that when dry , it will allow gasses to pass through it , but it will not allow liquids to pass through it . thus , instead of using vacuum valve 696 , vacuum source 695 is attached to pressure valve 665 . since plug 59 is porous , the air in the system passes through plug 59 to vacuum source 695 . as can be seen from the above , the manifold of the invention minimizes the amount of radioisotope needed for a procedure , and minimizes the hazards associated with manipulating a radioactive fluid .
a manifold system allows for the movement of a radioactive fluid from a container to a treatment balloon or other device , and the withdrawal of the radioactive fluid from the treatment device . the system allows for the convenient movement of the fluid , with minimal radiation exposure for those using the system . the manifold system is particularly useful in the use of radiation to prevent restenosis of arteries .