Abstract:
A syringe protecting device includes a casing ( 9 ) made of a material protecting against radiation, adapted to cover the syringe cylindrical body ( 3 ), which casing ( 9 ) is associated with a structure ( 10 ) likewise made of a material protecting against radiation, designed to form at least a partial protective shield on the rear end of the syringe, while allowing the syringe plunger ( 4 ) to be operated. In one particular embodiment, the protective shield is globally shaped like a cylindrical sleeve ( 10 ) provided with a base ( 18 ); the sleeve ( 10 ) is mounted sliding on the protective casing ( 9 ) by capping it through its rear end, and it comprises mechanism ( 20 ) for being removably secured to the stem ( 5 ) operating the syringe plunger ( 4 ).

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
   This application is a National Stage of International Application No. PCT/FR01/02728 filed on Sep. 3, 2001 under 35 U.S.C. § 371, which claims priority to French Application No. 00 11370 filed Sep. 1, 2000. 
   BACKGROUND OF THE INVENTION 
   This invention concerns the devices of the &lt;&lt;syringe protector&gt;&gt; type fitting the syringes of conventional type used notably for the injection of radioactive product(s) to ensure the protection of operators against exposure to high energy beams (for example the beams emitted by iodine 131, fluorine 18, oxygen 15 or carbon 11). 
   DESCRIPTION OF THE RELATED ART 
   The protection devices of such kind currently available on the market consist of an envelope substantially cylindrical in shape, of radioprotective material (lead; tungsten . . . ) suited to cover the cylindrical body of the syringe. This protective envelope comprises an orifice at its front end which enables the passage of the injection needle or of the reception cone of this needle; it also comprises an orifice at its rear end, which is used for the insertion and the withdrawal of the syringe body, as well as for operating the stem of the syringe piston. 
   These structures fulfill relatively well their protective role but there remains a risk of irradiation through the end orifices of the protective envelope. In particular, the operator of the syringe is exposed directly to this risk of irradiation through the rear end of this syringe, on the piston side. 
   SUMMARY OF THE INVENTION 
   This invention concerns therefore a solution to reinforce the protection provided by this kind of structure. 
   The protection device for syringe, according to this invention, comprises an envelope of radioprotective material, suited to cover the cylindrical syringe body, which envelope is associated with a structure also made of radioprotective material, which is laid out to form a protective shield at least partially at the rear end of the syringe body while enabling the operation of the piston of said syringe. 
   Still according to the invention, the protective envelope comprises an opening at its front end to let through the needle of the syringe or the reception cone of this needle, and an opening at its rear end for the insertion and the withdrawal of said syringe, as well as for operating the stem relative to its piston; moreover, there is provided an added-on structure of radioprotective material, which is laid out to form a protective shield at least partially opposite the opening arranged at the rear end of the protective envelope, while enabling the operation of the piston of the syringe. 
   According to a first embodiment, the protective shield has the general shape of a tubular jacket fitted with a bottom; this jacket covers the protective envelope at the rear end thereof and it comprises removable interconnection means with the stem which operates the piston of the syringe. 
   Preferably, the tubular jacket of radioprotective material is mounted to slide over the protective envelope. On the other hand, the cylindrical body of the tubular jacket has advantageously a length which is suited to cover the rear end of the protective envelope regardless of the extraction level of the stem which operates the syringe piston. 
   According to another feature, the removable interconnection means of the tubular jacket with the stem which operates the syringe piston consist of a lock laid out to press the head of said operating stem against the internal face of the bottom of said jacket. 
   According to another aspect, the protection device comprises means which enable to lock the tubular jacket on the protective envelope in order to block the position of the piston of the syringe; these particular means consist advantageously of two knurled knobs diametrically opposed. 
   Preferably, these knurled knobs are integral with the protective envelope and they co-operate with longitudinal openings provided in the tubular jacket, which openings emerge at the front end of this jacket. 
   According still to another aspect, the protection device according to this invention comprises removable interconnection means of the syringe body with the protective envelope. These means consist advantageously of a lock suited to press the end collar of the syringe body against the rear end of the protective envelope; the operating member of this lock protrudes across a longitudinal opening arranged in the tubular jacket, which opening emerges at the front end of said jacket. 
   According to another embodiment, the protective shield consists of two additional retractable half-parts laid out to be placed at the rear end of the protective envelope  27 , and whereof the junction edges are shaped to match the contour of the stem which operates the piston of the syringe. 
   Both additional half-parts can be mounted to slide on a guiding cradle positioned around the rear end of the protective envelope. This cradle holds both half-parts at the rear end of the protective envelope; it enables to bring both half-parts closer together in order to blank off the opening of the rear end of this protective envelope around the operating stem of the syringe piston, and it enables said half-parts to retract in order to position the syringe in the protective envelope, as well as its withdrawal. 
   Preferably, both additional half-parts are fitted with reverse shoulders on their junction edges, making up partial covering means. They also comprise advantageously extensions forming a covering skirt for the rear end of the protective envelope. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     But the invention will be better illustrated, without being limited thereto, by the following description of various particular embodiments, given solely for exemplification purposes and represented on the appended drawings wherein: 
       FIG. 1  is a lateral view of a first possible embodiment of a syringe protection device according to this invention, the protected syringe being here represented with its piston stem integrally &lt;&lt;retracted&gt;&gt;; 
       FIG. 2  is a sectional view along  2 - 2  of  FIG. 1 ; 
       FIG. 3  shows the same protection device with the stem of the piston of the syringe partially extracted; 
       FIG. 4  is a sectional view along  4 - 4  of  FIG. 3 ; 
       FIG. 5  is a perspective view of an embodiment variation of the syringe protection device illustrated on  FIGS. 1 to 4 ; 
       FIG. 6  is a longitudinal sectional view of another possible embodiment of a syringe protection device according to this invention, with a protective shield, here in &lt;&lt;open&gt;&gt; position, composed of two additional half-parts; 
       FIG. 7  is a sectional view along  7 - 7  of  FIG. 6 ; 
       FIG. 8  is a view similar to  FIG. 7 , the protective shield being here represented in &lt;&lt;closed&gt;&gt; position; 
       FIGS. 9 and 10  are perspective views, respectively ¾ rear and ¾ front views which show the protection device of  FIGS. 6 to 8  with the protective shield in &lt;&lt;open &gt;&gt; position; 
       FIGS. 11 and 12  are perspective views, respectively of ¾ front and ¾ rear views which show the same protection device with the protective shield in &lt;&lt;closed&gt;&gt; position. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 to 4  illustrate a first embodiment of a device  1  enveloping a syringe  2  to protect the operators against the radiation emitted by the radioactive product(s) intended to be injected. 
   The syringe  2  is of conventional type, made of a cylindrical syringe body  3  associated with an internal piston  4  which is operated by a stem  5  with a cross-like section. The syringe body  3  is extended by a truncated cone  6  at its front end, intended to receive the injection needle, not represented; its rear end comprises a peripheral collar  7 . 
   On the other hand, the external end of the stem  5  which operates the piston  4  is fitted with a flat head  8 . 
   The syringe protection device  1  consists mainly of a cylindrical envelope  9  which surrounds the syringe body  3 , and of a sliding jacket  10  which constitutes a protection shield by the rear end of said envelope  9 . 
   The cylindrical envelope  9  is made of radioprotective material, such as tungsten for example. It is lined internally by a sheath  11  of plastic material whereof the internal diameter corresponds, including the clearance, to the external diameter of the syringe body  3 . This sheath  11  facilitates the positioning and the withdrawal of the syringe body  3  within the envelope  9 ; according to the material used, it may also play a part in the radioprotection function. 
   The front end of the protective envelope  9  is fitted with an added-on truncated cowling  12 , also made of tungsten, fitted with a central orifice  13  letting through the truncated cone  6  of the syringe. This orifice  13  is reduced in size to limit the beam leakage; the cowling  12  also constitutes an end stop for the syringe body  3 . 
   At the rear end of the cylindrical envelope  9 , one can note the presence of a quick fastening/releasing means  14  which enables to maintain the syringe body  3  inside said envelope  9 . This fastening/releasing means  14  consists of a removable lock which presses the end crown  7  of the syringe body  3  against the rear end of the envelope  9 ; this lock is here in the form of a squeezer dog operated manually by means of a protruding extension  15 , and subject to a recall spring. 
   As regards the front end of the cylindrical envelope  9 , one can note the presence of a lead glass sight-window  16  which enables to access visually the useful portion of the graduations of the syringe body  3 . 
   The jacket  10  which is associated with the protective envelope  9  is also made of radioprotective material, such as tungsten for example. This jacket  10  has the general shape of a cylindrical tube  17  whereof the internal diameter corresponds, including the clearance, to the external diameter of the envelope  9 , and whereof one of the ends is blanked off by a bottom element  18 . Just before the bottom element  18  one can note the presence of an annular hollow  19  arranged in the tubular section  17 . 
   At the internal face of the bottom element  18 , a removable lock  20  in the form of a squeezer dog is arranged to fasten the stem  5  which operates the syringe piston  4 . This lock  20  has a structure similar to that of the locking member  14  described previously; it is accessible through an opening  21  arranged in the tubular section  17 , at the annular hollow  19 . 
   Over a portion of the length of the tubular element  17  there have been provided two longitudinal openings  22  diametrically opposed visible on  FIGS. 1 and 3 . Both these openings  22  emerge at the front end of the tubular element  17 ; they are intended to co-operate with knurled knobs  23  integral with the cylindrical envelope  9  in order to lock the tubular jacket  10  on said envelope  9 . One of both longitudinal openings  22  is also used to let through the extension  15  of the squeezer dog  14 . 
   The jacket  10  is placed on the cylindrical envelope  9  by the rear end thereof, once the syringe  2  has been inserted into its receiving structure  9 ,  11 . The cylindrical tube  17  is guided on the envelope  9  until its flat head  8  of the operating stem  5  is interconnected automatically with the bottom element  18  of the jacket, under the action of the lock  20 . 
   In this position, the jacket  10  forms a shield which protects the operator from the radiation emitted in the axis of the syringe through the rear opening of the protective envelope  9 . 
   The syringe  2  is then ready to be used, whereas the operation of its piston  4  also consists in making the jacket  10  slide over the envelope  9 . This sliding is possible when the knurled knobs  23  are loose; these knurled knobs  23  as well as the annular recess  19  may then be used as resting points for the fingers, when filling the syringe or when injecting the product. 
   The knurled knobs  23  are tight when one wishes to lock the position of the jacket  10  on the protective envelope  9 ; this locking enables to block the position of the piston  4  in the syringe body  3  and one thus avoids any accidental flow of the radioactive product through the injection needle. 
   The tubular section  17  of the jacket  10  has a length which is suited to cover the rear end of the protective envelope  9  regardless of the extraction level of the stem  5 . According to this extraction level, this tubular section  17  doubles more or less the cylindrical envelope  9  and it reinforces therefore the protection conferred by said envelope. 
   As represented on  FIGS. 1 and 2 , the length of the tubular section  17  is suited to cover completely the envelope  9  when the piston  4  of the syringe is integrally retracted.  FIGS. 3 and 4  show the syringe with the stem  5  which operates the piston  4  partially extracted. 
   When the injection of the radioactive product is complete, the syringe is extracted from its protective device by operating both squeezer dogs  14  and  20 . 
     FIG. 5  represents a variation of the embodiment of the syringe protection device illustrated on  FIGS. 1 to 4 . 
   Here, the protective envelope  9  is the same with its armoured sight-window  16  and with its cowling  12  through the central orifice of which passes the end truncated cone  6  of the syringe. There is also the tubular jacket  10  with its emerging longitudinal grooves  22  which co-operate with the knurled knobs  23  integral with the envelope  9 . 
   In this variation of the embodiment, the rear end section of the jacket  10  has been modified slightly; it does not comprise any annular hollows and the removable lock  20  corresponds to a model different of that illustrated on  FIGS. 1 to 4 . 
   On the other hand, the lock  14  which ensures removable interconnection between the syringe body and the protective envelope  9  extends through a longitudinal groove  25  which is dedicated thereto, independent of both grooves  22  used for letting through the feet of the knurled knobs  23 . 
     FIGS. 6 to 12  illustrate another possible embodiment of a syringe protection device according to this invention. 
   In the following description, one has kept the previous references allocated to the injection syringe for simplification purposes. 
   This syringe protection device  26  consists of a cylindrical envelope  27  of radioprotective material such as tungsten, associated with an added-on shield  28 , also made of radioprotective material such as tungsten, enabling removing blanking off of the rear opening of said envelope  27 . 
   The cylindrical envelope  27  receives the syringe body  3 ; its front end comprises an inner annular return  29  which only leaves a small central orifice  30  just sufficient for letting through the end truncated cone  6  of the syringe. 
   The added-on shield  28  consists of two additional half-parts  32  and  32 ′, here in the form of half-shells, which are suited to be positioned on the rear end of the cylindrical envelope  27 . Both these half-shells  32  and  32 ′ are mounted to slide on a supporting cradle  33  which, while ensuring their interconnection, enables to bring them closer to or further from a plane perpendicular to the axis of the protective envelope  27 . Both rectilinear parallel portions of the cradle  36 , which constitute the guiding portions of both half-shells  32  and  32 ′, are slightly tight against the cylindrical envelope  27  to maintain the shield  28  in position. To secure this hold, one may also contemplate to embed the central section of these rectilinear portions in throats formed on the periphery of the protective envelope  9 . 
   When both half-shells  32  and  32 ′ are spaced from one another, the syringe body  3  can be inserted in the protective envelope  27  ( FIGS. 6 ,  7 ,  9  and  10 ); once the syringe is in position, both these half-shells are brought closer manually to blank off the rear orifice of said envelope  27  while hugging the stem  5  which operates the piston of the syringe ( FIGS. 8 ,  11  and  12 ). 
   Both half-shells  32  and  32 ′ consist of a blanking off element  34 ,  34 ′ semicircular in shape, extended by a semi-cylindrical skirt section  35 ,  35 ′. These skirt sections  35 ,  35 ′ will hug the rear end of the envelope  27  when both half-shells  32  and  32 ′ are placed in radioprotection active position; they comprise lateral grooves  36  which guide half-shells  32 ,  32 ′ over the parallel rectilinear lengths of the cradle  33 . 
   The junction edges of both blanking off elements  34  and  34 ′ are formed to hug as much as possible the contour of the stem  5  with a cross-like section, when they are brought closer to one another. Solely the surface corresponding to the cross-like section of this stem  5  is not protected, which limits the risks of beam leakage. On the other hand part, these junction edges also comprise reverse shoulders,  37 ,  37 ′ which ensure partial covering of both blanking off elements  37 ,  37 ′ when they are juxtaposed, which enables to secure the radioprotection. 
   Once both half-shells  32 ,  32 ′ have been brought closer to one another, the stem  5  of the syringe can be operated conventionally by sliding through the protective shield  28 . 
     FIGS. 7 and 9  to  12  underline the presence of an armoured sight-window  38 , made of lead glass, fitting the front end of the cylindrical envelope  27  to access visually the graduations of the syringe body  3 . 
   Still according to another possible embodiment the cylindrical envelope which surrounds the syringe body  3  can be associated with a pellet, for example circular, made of radioprotective material, removably fixed on the flat head  8  of the syringe piston  4 .