Radiation shield for a safety syringe having a needle sheath

A syringe injection shield (100) is formed primarily from a radio-opaque substance, such as tungsten, to shield medical personnel from exposure to radiation during administration of radiopharmaceuticals to patients. Safety syringes (22) typically have a needle sheath that can be positioned around a needle (24) after administration of the radiopharmaceutical. The syringe injection shield of the present invention allows medical personnel to make the syringe “safe” before the used syringe is removed from the syringe injection shield. The syringe is safe when the needle sheath is positioned and locked in place around the needle to reduce the risk of needle stick. The syringe injection shield includes a toggle element (110) that can assume four different positions as follows: neutral; ready; hold; and release.

BACKGROUND OF INVENTION

Syringes, including those that are used to administer liquid radiopharmaceuticals pose a risk of needle stick. Various safety syringes have been developed to reduce the risk of needle stick, including the Monoject® sold by The Kendall Company, a business of Tyco International Ltd., having a place of business at 15 Hampshire St., Mansfield, Mass. and the SafetyLok® sold by Becton-Dickson and Company (B-D) having a place of business at 1 Becton Drive, Franklin Lakes, N.J. An illustrative example of the Monoject(E) type of technology includes that disclosed in U.S. Pat. No. 5,156,599 issued on Oct. 20, 1992, which is incorporated herein by reference. Illustrative examples of the Safety-Lok® technology include that disclosed in: U.S. Pat. No. 6,221,052, issued on Apr. 24, 2001, which is incorporated herein by reference; U.S. Pat. No. 6,432,087, issued on Aug. 13, 2002, which is incorporated herein by reference; and U.S. Pat. No. 6,368,303, issued on Apr. 9, 2002, which is incorporated herein by reference.

Both the Monoject® and the Safety-Lok® safety syringe have a cylindrical needle sheath that can be repositioned and locked after administration of a radiopharmaceutical to surround the needle to reduce the risk of needle stick.

Safety syringes with an extendable sheath design are also disclosed in: U.S. Pat. No. 4,994,045, issued to Ranford on Feb. 19, 1991, which is incorporated herein by reference; U.S. Pat. No. 4,998,924, issued to Ranford on Mar. 12, 1991, which is incorporated herein by reference; U.S. Pat. No. 4,743,233, issued to Schneider on May 10, 1988, which is incorporated herein by reference; U.S. Pat. No. 5,403,287, issued to Talonn et al. on Apr. 4, 1995, which is incorporated herein by reference; U.S. Pat. No. 5,163,916, issued to Sunderland on Nov. 17, 1992, which is incorporated herein by reference; U.S. Design Patent No. 313,470, issued to Talonn et al. on Jan. 1, 1991, which is incorporated herein by reference; and U.S. Design Patent No. 344,355, issued to Talonn et al. on Feb. 15, 1994, which is incorporated herein by reference.

The administration of radiopharmaceuticals can also pose a radiation exposure risk to medical personnel. The use of syringe injection shields reduces this risk. Biodex Medical Systems, Inc. of 20 Ramsay Rd., Shirley, N.Y. sells the Pro-Tec® II syringe injection shield. The Pro-Tec® II syringe injection shield uses tungsten shielding, a lead glass window and fits various disposable syringes. A thumbscrew holds the syringe in place.

Biodex also sells the Pro-Tec® III syringe injection shield. The Pro-Tec® III syringe injection shield is produced in two different models. One model is for regular syringes. The other model is designed to function with one or more safety syringes such as the Safety-Lok® sold by B-D or the Monoject® sold by The Kendall Company. There are two ways to remove a used safety syringe from the Pro-Tec® III syringe injection shield.

One approach is to invert the combination of syringe injection shield and used safety syringe so that the needle is pointing up relative to the floor. The release button is then pressed, allowing the used syringe to fall by gravity from the shield. Thereafter, the syringe is typically placed in a pharmaceutical pig (needle down) for transport to a nuclear pharmacy for disposal of the used safety syringe. Unfortunately, the needle remains exposed during the aforementioned disposal procedure. Approximately 50% of all needlesticks occur after injection and before disposal.

Another approach is to position the combination of syringe injection shield and used safety syringe so that the needle is pointing towards the floor. The release button is pressed, allowing the used syringe to be manually removed from the syringe injection shield. Thereafter, the syringe is typically placed in a pharmaceutical pig (needle down) for transport to a nuclear pharmacy for disposal of the used safety syringe. Unfortunately, the needle also remains exposed during the aforementioned disposal procedure. There is a need for a syringe injection shield that will allow a safety syringe to be placed in the “safe” position before the syringe is removed from the syringe injection shield. A safety syringe is in the safe position when the needle is covered by a sheath or other protective element and the sheath is locked in position relative to the needle.

There are various ways to place a safety syringe in the safe position, which is well known to those skilled in the art. For example, the Monoject® safety syringe is rotated to a locked position after the needle has been retracted into the needle sheath. The Safety-Lok® safety syringe uses a different locking procedure. First, the needle is retracted into the needle sheath, then the barrel is pulled longitudinally into a locked position. Other safety syringes that use different locking systems may be suitable for use with this invention.

The Pro-Tee® III syringe injection shield has a toggle element that can assume three positions, which are as follows: neutral; ready; and release. This prior art toggle element is in the neutral position when there is no syringe in the injection shield. The ready position for this prior art toggle element is when a syringe is in the injection shield. Finally, this prior art toggle element is in the release position when the syringe is being removed from the shield.

The prior art toggle element associated Pro-Tec® III syringe injection shield will not allow the syringe to be made safe prior to removal of the syringe from the shield due to the fact that this prior art toggle element cannot hold a syringe sheath in place so the sheath can be locked in position relative to the barrel and needle.

Many radiopharmaceuticals are injected into a patient's blood vessel. To confirm that the needle is properly positioned in the patient's blood vessel, medical personnel typically pull back on the syringe plunger to draw blood through the needle into the barrel of the syringe. If blood cannot be seen in the barrel of the syringe, the needle is repositioned and the process is repeated. The radiopharmaceutical is administered after the correct position of the needle has been confirmed by the presence of blood in the syringe barrel. For this reason, prior art syringe shields typically include a lead glass insert so medical personnel could attempt to see inside the barrel of the syringe while it was positioned in the syringe shield. Unfortunately, it is hard to see through the lead glass into the syringe barrel to confirm the presence of blood. There is a need for a syringe injection shield that allows easy visual confirmation of needle placement in a blood vessel. The present invention is directed to overcoming one or more of the problems set forth above.

SUMMARY OF INVENTION

The syringe injection shield of the present invention includes a generally tubular member that is sized to receive a safety syringe. The present invention is intended for use with various safety syringes including, but not limited to, the Monoject® safety syringe and the Safety-Lok® safety syringe. The tubular member of the present invention may be formed in different sizes to accommodate safety syringes from different sources. The tubular member is typically formed from tungsten or some other radio-opaque substance, which shields medical personnel from at least a portion of the radiation emitted from the radiopharmaceutical. A toggle housing is formed in the tubular member to support a movable toggle element. Unlike the prior art, the toggle element has four positions, which are as follows: a neutral position; a ready position; a hold position; and a release position. The toggle element forms a contact point that engages the needle sheath of a safety syringe when the toggle element is in the hold position. The toggle element allows medical personnel to make the safety syringe “safe” before the used syringe is removed from the syringe injection shield. In the preferred embodiment, the syringe injection shield of the present invention is slightly shorter than the safety syringe to make it easier to confirm proper placement of the needle in a blood vessel. However, in alternative embodiments, the length of the syringe injection shield could be flush with the end of the safety syringe. These and other aspects will become apparent to those skilled in the art in light of the following disclosure and accompanying drawings.

DETAILED DESCRIPTION

FIG. 1is a section view of a safety syringe inserted into a prior art syringe injection shield. The prior art syringe injection shield is generally identified by the numeral20and the safety syringe is generally identified by the numeral22.

The safety syringe22has a needle24, not shown to scale, that engages a luer lock26, the exact configuration of which is well known to those skilled in the art. The luer lock26is positioned on one end28of the syringe barrel30. A plunger31fits into the opposite end34of the barrel30. An elastomeric seal32is positioned on one end of the plunger31and a push tab33is positioned on the opposite end. Finger tabs36are formed on the end34of the barrel30, opposite the luer lock26. The radiopharmaceutical38is contained inside the barrel30between the plunger32and the end28.

A movable needle sheath40surrounds the barrel30and extends from the finger tabs36to the end28. The barrel30and the needle24move relative to the needle sheath40as will be described below. A locking lug assembly41is positioned on the exterior of the end28of the barrel30and the interior of the needle sheath40. Various locking lug assemblies known to those skilled in the art may be suitable for this purpose. To make the safety syringe22safe, the needle24is moved from the extended position, as shown in this figure to a retracted position, shown in subsequent figures and the barrel30is rotated relative to the needle sheath40to lock the needle sheath40in position surrounding the needle24.

The syringe injection shield20includes a generally tubular member42that is formed from a radio-opaque material such as tungsten to reduce radiation exposure to medical personnel. A lead glass insert44is positioned in the tubular member42. A toggle housing46supports a toggle element48that pivots on a shaft50. The toggle element48defines a contact point52that engages the needle sheath40. Opposite the contact point52is the release button54. Below the release button is a recess56sized to receive one end of a spring58. A portion60of the toggle housing46forms a spring receiver61that receives the opposite end of the spring58. The spring58is under compression when positioned as shown in this figure, between the release button54of the toggle element48and the spring receiver61. The purpose of the toggle element48in the prior art syringe injection shield20is to hold the safety syringe22in place during administration of the radiopharmaceutical. Unfortunately, the toggle element48of the prior art syringe injection shield20cannot hold the safety syringe22in place during rotation of the barrel30and therefore the safety syringe22cannot be made safe prior to withdrawal from the injection shield.

The toggle element48of this prior art injection shield20has the following three positions: neutral; ready; and release. InFIG. 1, the toggle element48is in the ready position. The contact point52is in contact with the needle sheath40. When the release button54is depressed, the prior art toggle48is in the release position, not shown. In the release position, the contact point52is not in contact with the needle sheath40. When there is no safety syringe22in the injection shield, this prior art toggle element48is in the neutral position.

FIG. 2is a perspective view of the syringe injection shield of the present invention and a safety syringe22, prior to insertion of the safety syringe22into a syringe injection shield. The syringe injection shield of the present invention is generally identified by the numeral100. The syringe injection shield100includes a generally tubular member102that is formed from a radio-opaque material, such as but not limited to tungsten, to reduce radiation exposure to medical personnel from the radiopharmaceutical. The generally tubular member102is sized to receive the safety syringe22. The tubular member has a distal end104and a proximal end106.

A toggle housing108is mounted on the tubular member102and the toggle housing108is sized to receive a movable toggle element110. A shaft112is mounted in the toggle housing108and the shaft112passes through the toggle element110allowing it to pivot inside the toggle housing108. Unlike the prior art, the toggle element110of the present invention has four positions as follows: neutral; ready; hold; and release. Each of these four positions will be show in the following figures and discussed in sequential operational steps. A lead glass insert114is also positioned in the toggle housing108.

FIG. 3is a section view of the syringe injection shield100ofFIG. 2and the safety syringe22prior to insertion of the safety syringe22into the syringe injection shield100. The toggle element110is in the neutral position. The toggle element110forms a contact point118, an elongate tang120and a release tang122. A recess124is formed beneath the release tang122and is sized to hold one end of the spring128. A spring holder126is formed in a portion of the toggle housing108and is sized to hold the other end of the spring128. When the spring128is in position as shown in this figure, the spring128is under compression urging the contact point118of the toggle element110into the neutral position. The radiopharmaceutical38has already been drawn into the barrel30of the safety syringe22. To reduce radiation exposure to medical personnel during administration of the radiopharmaceutical to the patient, the loaded safety syringe22is first placed into the syringe injection shield100as shown in the next figure.

FIG. 4is a section view of the syringe injection shield100and safety syringe22after the syringe has been inserted into the shield. The toggle element110is now in the ready position. The needle24is in the extended position and is exposed, prior to administration of the radiopharmaceutical38to a patient. In the ready position, the contact point118of the toggle element110engages the exterior surface of the needle sheath40. As previously discussed, radiopharmaceuticals are often administered into the patient's blood vessel. To confirm proper placement of the needle24in the blood vessel, not shown, medical personnel pull back on the plunger31as indicated by the arrow to pull blood from the vessel through the needle into the barrel where the blood or the lack thereof can be observed by the medical personnel. The end28of the barrel30extends beyond the proximal end106of the syringe injection shield100. To steady the syringe100for pullback, the finger tabs36are held in a fixed position relative to the syringe injection shield100by the medical personnel.

A portion120of the barrel30extends beyond the end104of the syringe shield100. This extended portion120facilitates observation of the fluid in the barrel30by the medical personnel to confirm proper needle placement. This is easier and faster to see than peering through the dark lead glass114into the dark interior of the syringe shield100. The extended portion120is exaggerated in the drawings to emphasize this feature. In the commercial embodiment, the length of the extension120is kept to a minimum to reduce radiation exposure. After confirmation of proper needle placement, the plunger31is fully depressed, as shown in the next figure, causing the radiopharmaceutical to flow from the barrel30through the needle24into the patient.

FIG. 5is a section view of the syringe injection shield100and safety syringe22ofFIG. 4after administration of the radiopharmaceutical. The plunger31has been fully depressed and the seal32is in contact with the end28of the barrel30.

FIG. 6is a section view of the safety syringe22and the syringe injection shield100after the radiopharmaceutical has been administered to the patient. The needle24and barrel30have been moved from the extended position ofFIGS. 4 and 5to the retracted position ofFIG. 7.

The toggle element110is then placed in the hold position as shown in this figure. In the hold position, pressure is applied by medical personnel to the elongate tang120of the toggle element110as indicated by the arrow so the contact point118will hold the needle sheath40in place relative to the injection shield while the finger tabs36and the barrel30are rotated as indicated by the arrow.

The amount of pressure needed on the toggle in the hold position can vary depending on the size of the elongate tang120, the configuration of the contact point118, the locking lug assembly41and the type of safety syringe22. However, pressure from about 13 to about 20 pounds and more preferably from about 15 to about 18 pounds on the toggle has been sufficient to hold the needle sheath in place while the barrel is rotated and the syringe is made safe. Optimally, a pressure of about 16.5 pounds on the elongate tang will be sufficient while in the hold position.

FIG. 7is a section view of the safety syringe22and the syringe injection shield100. The toggle element110is in the hold position in this figure. In the hold position, pressure continues to be applied by medical personnel to the elongate tang120of the toggle element110as indicated by the arrow so the contact point118will hold the needle sheath40in place relative to the syringe barrel while the finger tabs36and syringe barrel30are being rotated as shown by the circular arrow150to properly engage the locking lug assembly41, not shown. Locking lug assemblies are known in the art. In this figure, the needle24has been moved to the fully retracted position. The safety syringe22has been “made safe” after the needle24has been moved from the extended to the retracted position and the syringe barrel30has been rotated and locked in place relative to the needle sheath40. When properly engaged, the locking lug assembly41prevents the needle24from being extended beyond the end of the needle sheath40. The locked needle sheath40covers the needle24and reduces the risk of needle stick during disposal of the used safety syringe22.

FIG. 8is a section view of the safety syringe22and the syringe injection shield100. The toggle element110is in the release position. In the release position, pressure is applied by medical personnel to the release tang122of the toggle element110as indicated by the arrow so the contact point118does not touch the needle sheath40. The safety syringe is then removed from the shield for disposal. The safety syringe22has been “made safe” prior to removal from the syringe injection shield100and the needle14is protected by the needle sheath40.

FIG. 9is a section view of the syringe22and the syringe injection shield100. The toggle element110is in the neutral position. The safety syringe22has been completely removed from the syringe injection shield100and is ready to be disposed. The needle24is protected by the needle sheath40and full use has been made of the features of the safety syringe22.