U.S. patent application number 09/813063 was filed with the patent office on 2001-09-06 for method and device for pre-filling a syringe with a contrast agent.
Invention is credited to Nemoto, Shigeru.
Application Number | 20010018937 09/813063 |
Document ID | / |
Family ID | 26582467 |
Filed Date | 2001-09-06 |
United States Patent
Application |
20010018937 |
Kind Code |
A1 |
Nemoto, Shigeru |
September 6, 2001 |
Method and device for pre-filling a syringe with a contrast
agent
Abstract
A method and device for filling a syringe with a chemical
solution such as a contrast agent is disclosed. The device has a
cylinder holder, a piston holder, a driving mechanism to move the
piston holder relative to the cylinder holder, a keyboard to input
test conditions, and a computer. Based on the test conditions, the
computer calculates the volume of the chemical solution necessary
for a patient. The piston holder is allowed to aspirate the precise
volume necessary for the patient from a bottle where the chemical
solution is stored. Thus the correct and necessary volume of the
chemical solution is transferred from the bottle to the syringe,
which minimizes the waste of the chemical solution.
Inventors: |
Nemoto, Shigeru; (Tokyo,
JP) |
Correspondence
Address: |
Robert C. Beck
Suite 100
2900 Thomas Avenue South
Minneapolis
MN
55416-4477
US
|
Family ID: |
26582467 |
Appl. No.: |
09/813063 |
Filed: |
March 20, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09813063 |
Mar 20, 2001 |
|
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|
09471464 |
Dec 22, 1999 |
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Current U.S.
Class: |
141/27 ; 141/18;
604/416 |
Current CPC
Class: |
A61M 5/1782 20130101;
A61M 5/1456 20130101; A61M 5/1458 20130101; A61M 5/007 20130101;
A61M 2209/045 20130101 |
Class at
Publication: |
141/27 ; 141/18;
604/416 |
International
Class: |
B65B 001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 1998 |
JP |
10-373095 |
Claims
What is claimed is:
1. A filling device for filling a syringe with a chemical solution
stored in a container, the syringe having a barrel and a piston,
the filling device comprising: a cylinder holder adapted to hold
the syringe barrel; a piston holder adapted to hold the syringe
piston; a syringe detector for detecting the presence of a syringe
in the device; a driving mechanism attached to the piston holder,
the driving mechanism being capable of moving the piston holder
relative to the cylinder holder in a forward and a reverse
direction; an input mechanism adapted to receive inputted test
conditions; a calculation portion to calculate an appropriate
volume of the chemical solution based on the test conditions;
whereby the driving mechanism moves the piston holder according to
the volume calculated by the calculation portion in the filling
direction if and only if the syringe is present in the device.
2. The filling device according to claim 1, wherein the syringe
detector is a photoelectric monitor that detects the presence of a
syringe component.
3. The filling device according to claim 1, wherein the syringe
detector is a current monitor that detects the level of current
used to operate the driving motor.
4. The filling device according to claim 1, wherein the chemical
solution is a contrast agent for X-ray CT, magnetic resonance
imaging, angiography or urography.
5. The filling device according to claim 1, wherein the device
further comprises a data storage mechanism.
6. The filling device according to claim 1, wherein the input
mechanism is a keyboard.
7. The filling device according to claim 1, wherein the calculation
portion is a computer.
8. The filling device according to claim 4, wherein the data
storage mechanism is a data storage system in a computer.
9. The filling device according to claim 1, wherein the driving
mechanism comprises a stepping motor, a ball screw shaft, and a
ball screw nut engaged with the ball screw shaft.
10. The filling device according to claim 1, wherein the driving
mechanism and the calculation mechanism are accommodated in one
housing.
11. The filling device according to claim 1, wherein the test
conditions are selected from the group consisting of: scanning
condition, test region, patient's weight, and contrast agent
description.
12. The filling device according to claim 1, wherein the test
conditions include an indication of the cross-sectional area of the
syringe.
13. A syringe filling system comprising: a) a syringe having a
piston with a piston flange and a barrel of a known cross-sectional
area; b) a barrel holder adapted for holding the piston barrel; c)
a piston holder adapted for receiving the piston flange, the piston
holder capable of movement relative to the barrel holder; d) a
driving mechanism attached to the piston holder, the driving
mechanism moving in response to a driving signal; e) a data
receiving interface for receiving test conditions; f) a processing
unit for calculating a volume in response to test conditions; and
g) a signal generator that generates a driving signal to instruct
the driving mechanism to move the piston holder solely in the
reverse direction to aspirate and sufficiently fill the syringe
according to the calculated volume.
14. The syringe filling system of claim 13, further comprising a
bottle containing a fluid, and a connecting tube connecting the
bottle to the syringe, wherein the driving signal compensates for
the dead space in the connecting tube.
15. The syringe filling system of claim 13, further comprising a
means for determining the cross-sectional area of the syringe.
16. The syringe filling system of claim 13, wherein the data
receiving interface is a computer to computer interface for
receiving data from a separate computer containing patient
data.
17. The syringe filling system of claim 13, further comprising a
data storage media containing standard usage information regarding
the use of at least one contrast agent, wherein the processing unit
uses the information in the data storage media along with the test
conditions to calculate the volume.
18. A method for filling a syringe with a chemical solution by
transferring the chemical solution stored in a container to the
syringe, comprising the steps of: a) mounting a syringe barrel and
a piston to a cylinder holder and a piston holder, respectively,
equipped in a filling device, b) connecting the tip of the syringe
to a connecting tube attached to the container storing the chemical
solution, c) inputting test conditions with an input means in the
filling device, d) calculating necessary volume of the chemical
solution for administration with a calculating means in the filling
device, e) detecting the presence of the syringe within the filling
device; f) moving the piston holder based on the calculated
chemical solution volume, if and only if the syringe presence is
detected, whereby the necessary volume of the chemical solution is
aspirated from the container and fills the syringe.
19. The method of claim 18, wherein the process of inputting the
test conditions includes inputting an indication of the size of the
syringe barrel.
20. The method of claim 18, further comprising the step of
determining the cross-sectional area of the syringe.
Description
CROSS REFERENCE
[0001] The present case is a continuation in part of U.S. Ser. No.
09/471,464 filed Dec. 22, 1999 entitled A METHOD AND DEVICE FOR
FILLING A SYRINGE WITH A CHEMICAL SOLUTION now abandoned.
TECHNICAL FIELD
[0002] The present invention relates to a device and a method for
transferring a fluid (such as a chemical solution or contrast agent
used for magnetic resonance imaging, X-ray CT, angiography,
urography and the like) from a container (such as a bottle) to a
syringe so as to fill the syringe with the fluid.
BACKGROUND OF THE INVENTION
[0003] Contrast agents, such as those used for magnetic resonance
imaging ("MRI") and X-ray CT imaging, are often used in liquid form
having a high viscosity. These contrast agents are generally sold
and provided to hospitals or other testing facilities in a bottle
or syringe. When the contrast agent is provided in a syringe, it
can be directly attached to an automatic injector designed for the
contrast agent and can be used at once. In this way, filled
syringes allow for easy and simple administration to the patient.
However, if the contrast agent is not supplied in syringe form, the
agent must be transferred from the bottle to the syringe prior to
administration to the patient.
[0004] Unfortunately, it takes a long time and much effort to
aspirate a viscous fluid into the syringe, by hand. Although it is
possible to aspirate the contrast agent into a syringe using an
automatic injector, this causes difficulties. For instance, loading
a syringe is not possible while the injector is being used to
deliver contrast agent to the patient.
[0005] In addition, the volume of the contrast agent used during a
procedure depends upon the patient's weight and the type of
diagnostic study.
[0006] In conventional practice all or most of the chemical
solution in the bottle is transferred to the syringe. Only a
portion of the contents of the syringe may be required for the
study. Since the necessary volume is then administered there can be
substantial waste.
SUMMARY OF THE INVENTION
[0007] The present invention overcomes the problems of the prior
art technology. The objective of the present invention is to
provide a filling device and a filling method which are used for
slowly filling the syringe with the correct and necessary volume of
a viscous chemical solution. This filling device and method thus
transfers the contrast agent from the container to the syringe
while minimizing the waste of the contrast agent remaining in the
syringe after the procedure.
[0008] Accordingly, the present invention is directed to a filling
device for filling a syringe with a chemical solution. This is
accomplished by transferring the chemical solution stored in a
container to the syringe. The device includes a cylinder holder to
hold the syringe barrel, a piston holder to hold the syringe piston
and a driving mechanism to move the piston holder relative to the
cylinder holder. An input mechanism to input test conditions is
provided. This device is implemented with a microprocessor system
that can calculate the volume of the chemical solution based on the
test conditions. The calculated volume is used to generate a
control signal to drive a motor whereby the piston holder is
allowed to move according to the volume calculated with the
calculation mechanism.
[0009] Another aspect of the present invention is directed to a
method for filling a syringe with a chemical solution by
transferring the chemical solution stored in a container to the
syringe, comprising the steps of: mounting a syringe barrel and a
piston to a cylinder holder and a piston holder, respectively,
connecting the tip of the syringe to the connecting tube attached
to the container storing the chemical solution, inputting test
conditions with an input mechanism in the filling device,
calculating the necessary volume of the chemical solution for
administration with a calculating means in the filling device,
moving the piston holder based on the calculated chemical solution
volume, thereby the necessary volume of the chemical solution is
aspirated from the container and fills the syringe.
[0010] In one embodiment of the present invention, the filling
device may be deigned for exclusive use as a filling device. In
this embodiment the filling device detects the presence of a
syringe for pre-filling and locks out "forward" syringe plunger
motion which could contaminate the source of contrast agent. This
safety feature may be subject to a manual override, which will not
commonly be used. The interlock feature may rely on a detector for
detecting the physical presence of the syringe or a software
interlock may be used which simply requires the user to confirm
that the syringe has been removed from the machine before allowing
plunger motion that may potentially contaminate the container of
contrast. Also, the use of a monitor for motor current can be used
to detect the presence of a syringe for interlock functions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows an embodiment of the chemical solution-filling
device of this invention.
[0012] FIG. 2 is a flow chart showing the chemical solution filling
method of this invention.
[0013] FIG. 3 is an enlarged view (perspective view) to show an
example of the chemical solution-filling device of this
invention.
[0014] FIG. 4 is an enlarged view (top view) to show an example of
chemical solution filling device of this invention.
[0015] FIG. 5 shows an embodiment of the chemical solution-filling
device of this invention.
[0016] FIG. 6 is an alternate flow chart showing the chemical
solution filling method of this invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] FIG. 1 shows an embodiment of a chemical solution-filling
device of the present invention. The filling device shown in this
embodiment comprises a main body 1 and a calculator portion 2.
Equipped with the main body 1 are a cylinder holder 3 to a hold the
barrel of a syringe 5, a piston holder 4 which holds the piston of
the syringe 5 and can move relative to the cylinder holder, and a
driving portion, not shown in this figure, which includes a motor,
also not shown, to move the piston holder 4. In general, the
structures required to drive the piston holder 4 include a
leadscrew and stepper motor. These devices are well known in this
field and further description is not required. The stepper motor is
under the digital control of the calculation portion 2. The
calculation portion may also monitor the amount of current required
to drive the stepper motor and in this fashion acquire information
used for filing the syringe. The calculation portion 2 contains an
input interface, such as a keyboard, to input diagnostic test
conditions, a display and a computer or other processing unit as a
calculation and data storage means inside of the calculation
portion 2.
[0018] As shown in FIG. 1, the barrel and the piston of the syringe
5 are attached to the cylinder holder 3 and the piston holder 4,
respectively. The syringe 5 is connected to the chemical solution
bottle 6 through the connecting tube 8. The tube set and bottle may
be coupled with a conventional Luer or septum-piercing "spike".
Every effort is made to minimize the dead volume in the tube
set.
[0019] A sensor may be provided to detect the presence of a syringe
in the filling device. For example an optical transmitter 18 may
project light to an optical receiver 19, located in the coupler or
piston holder 4. In this instance the presence of the flange of the
syringe plunger will interrupt the beam and notify the software
that the syringe is present. Barrel detection is also an
alternative approach to detection of the syringe.
[0020] The method of using the present invention is shown in the
flowchart in FIG. 2. First the test conditions are input into the
calculation portion 2 through the keyboard as shown in step 10. The
test conditions used in a diagnostic X-ray CT, for instance, would
include the scanning condition of X-ray CT, the test region, the
patient's weight, and a description of the contrast agent. These
actual input conditions should be sufficient to calculate the
correct amount of contrast agent used for the procedure. The test
conditions actually inputted in step 10 can be changed as necessary
to be appropriate for the particular test. The calculation portion
2 may be menu driven and queries may be presented to the user which
include the type of study to be performed.
[0021] In step 11, the computer in the calculation portion 2 then
calculates the volume of the contrast agent to be used. This
calculation is based on the test conditions inputted in step 10.
The necessary standard volume of contrast agent or calculation
coefficient for each input item can be stored in database in
advance and used to calculate the volume according to the test
conditions. For example, the necessary injection volume for a
patient based on his weight is stored. This information is
represented by box 12 in the flow chart of FIG. 2. The correct and
precise volume is then calculated based on this information as
altered by the test conditions of step 10. In the instances where a
menu is used to interrogate a user a lookup table maybe used to
supply the information represented by 12.
[0022] Once step 11 determines the injection volume of the chemical
solution, the moving distance of the syringe piston is calculated
in step 13. The moving distance is based upon the volume calculated
in step 11 and the known cross-sectional area of the barrel of the
syringe 5. If syringes 5 of varying cross-sectional area are to be
used in the present invention, then it is possible to determine
which syringe 5 is being used by requiring that the type of syringe
being used be inputted with the other test conditions in step 10.
Alternately, a simple mechanical device (not shown in the figures)
could be moved into contact with the syringe 5 to determine which
of the possible syringes are being utilized. In addition to merely
calculating the piston moving distance required to create the
volume calculated in step 11, step 13 may also take into
consideration the required moving distance of the piston to
compensate for the dead space in the connecting tube 8.
[0023] Once the piston moving distance is determined, a signal is
sent to the motor in the main body 1 to move the piston holder 4
(and hence the piston of syringe 5) the required distance in step
14. By so instructing the motor, the piston is moved and the
required amount of chemical solution is aspirated into the syringe
5. This is defined as the "filling" direction labeled in FIG. 1
with the arrow 36.
[0024] If the aspiration speed is too fast, leakage of air from
connectors or damage of the syringe occurs frequently. Therefore,
it is also preferable that the aspirating condition of the filling
device, such as aspirating speed or aspirating pressure, can be
altered. Since the aspirating condition differs depending on the
properties of the chemical solution, solution temperature and the
type of the syringe and the like, it is specifically preferred that
the aspirating condition should be calculated by the computer based
on these data. Stepper motor current draw or torque can also be
used to modify the withdrawal speed of the piston.
[0025] As mentioned previously, the filling device of the present
invention may be designed for exclusive use as the filling device
or may also serve as an injector for injecting the chemical
solution to the patient. In cases where the device is designed for
exclusive use as a filling device, the syringe filled with a
chemical solution by this filling device will be used with, but
separately from, an injector. The chemical solution will be
injected to a patient through a delivery extension tube attached to
the tip of the syringe. When the filling device also serves as an
injector, injection is conducted through a delivery extension tube
attached to the tip of the syringe in place of the connecting tube
8. Alternatively, injection may also be conducted by changing the
path using a three-way valve from a connecting tube to a delivery
extension tube. Attached to the end of the delivery tube would be a
suitable apparatus for injection, such as a butterfly needle and
the like or catheters depending on the test regions.
[0026] When the injection of the chemical solution is conducted,
the path though the syringes tip to the test region in the
patient's body may constitute a dead space. This dead space may
also preferably be taken into consideration in determining the
moving distance of the piston. The dead space is labeled 35 in FIG.
1.
[0027] Using the filling device of this invention, the optimum
volume of the chemical solution fills the syringe 5 with no need to
recalculate or control the volume when the chemical solution is
injected to the patient. Therefore, the present invention allows
the use of an injection device with a relatively simple mechanism
as a device for the administration of chemical solution to the
patient. Also, there is no waste of chemical solution since only
the necessary volume of chemical solution is transferred from the
bottle 6 to the syringe 5. It is especially effective when
expensive chemical solutions are used or the chemical solution is
stored in a bottle 6 of large capacity.
[0028] The embodiment explained so far is the case where only one
kind of chemical solution is used. However, a chemical solution may
be used after being diluted with physiological saline solution or
pure water in order to obtain a suitable concentration of iodide,
for example for X-ray CT, or a suitable viscosity of the fluid. In
such cases, the dilution ratio of the chemical solution is
calculated by the computer to give the volume of the chemical
solution and the diluent, thereby the moving distance of the piston
is determined. The aspiration of the chemical solution and the
diluent is achieved, for example, using the system shown in FIG. 5.
In this system the path of the chemical solution from chemical
solution bottle 8 and the diluent bottle 36 may be switched using a
three-way valve 37. The switching may be operated manually or
automatically synchronous to the movement of the piston. In some
instances, where mixing is required, the computer may instruct the
piston to aspirate from each container and then to refill and
re-aspirate from a container to provide very good mixing.
[0029] The example of a contrast agent for X-ray CT was used above,
although this device can be used to transfer other chemical
solutions, both viscous and non-viscous. The main purpose is to
transfer other viscous solutions, however, such as contrast agents
for MRI, angiography or urography.
[0030] The only requirement for the cylinder holder 3 and the
piston holder 4 is that they are adapted to the barrel and piston,
respectively, of the syringe 5 being used. For example, FIG. 1
shows cylinder holder 3 and piston holder 4 that fit closely with
the brim of the syringe barrel and the syringe piston. FIGS. 3 and
4 show enlarged views of the flange of the piston 7 being held by
the piston holder 4. In the preferred embodiment, the channel of
the piston holder 4 is wider by about 1 mm than the thickness of
the piston flange 7 in order to make it easier to put in and take
out the piston 5. Although the piston holder 4 is shown in the
figures with a semi-circular shape having an interior groove
slightly larger the thickness of a circular piston flange 7,
nothing in the present invention is intended to limit the piston
holder 4 to such shapes. For instance, those with standard skill in
the art would be aware of numerous other configurations of piston
flange 7, and could develop corresponding piston holders 4 to hold
such flange 7. These other configurations are well within the scope
of the present invention.
[0031] There is also no particular limitation for the mechanism
used to move the piston holder 4 the distance calculated in step
13. For instance, the mechanism might utilize a stepping motor, a
ball screw shaft and a ball screw nut that is engaged with the ball
screw shaft and supports the piston holder 4. In this case, the
stepping motor would drive the rotation of the ball screw shaft
based upon the signal transmitted from the calculating mechanism as
described in connection with step 14. This causes the movement of
the ball screw nut together with the piston holder in the
longitudinal direction of the ball screw shaft axis. The necessary
interface to drive the stepping motor the calculated distance is
well known in the prior art. It is also well known that the current
or force required to drive the stepper motor can be monitored
electrically by software. In FIG. 6 process 30 monitors the force
or a proxy for force.
[0032] Although not described above in connection with FIG. 2, it
is also possible to include a preliminary step in the aspiration
process to remove air from the syringe 5 and connecting tube 8.
This step would involve programming the aspirator to aspirate the
necessary volume of chemical solution after confirming that the
syringe piston is pushed automatically all the way to the end. This
would result in all air being removed from the system prior to
aspiration of the chemical solution.
[0033] Although the embodiment illustrated in FIG. 1 shows the
example of single-piece construction in which the calculating
portion 2 and the piston driving main body 1 are accommodated in
one housing, separate-type construction can also be used. It is
desirable that the motion of forward, backward and stop, and
aspiration speed (moving speed) and the like can be set or
controlled not only at the calculating portion 2, but also at the
main body 1 of the aspiration device. Controls for doing so are
shown on the main body 1 in FIG. 2. This enables both manual
operation and automatic operation. While these controls are present
on the preferred embodiment shown in the figures, such controls are
not necessary and it is possible that controls are located within
the calculating portion 2.
[0034] Turning to FIG. 6 there is shown an alternate flow chart for
operating the syringe-filling device. This version makes use of the
syringe sensor. As stated above it is possible for air to enter the
system and purging of the air from the filled syringe is an
important safety step. However, it is undesirable to clear air from
the syringe while connected to the container 6. Any reverse flow
may contaminate the contrast agent in the container 6, which is
very undesirable. In this alternate system once a syringe is placed
in the machine only a drawing motion is permitted for the plunger.
Once again the plunger speed is optimized for the viscosity of the
contrast agent. The possibility of contamination is eliminated by
restricting the motion of the syringe.
[0035] When a syringe is in the device the motor current required
to drive the plunger rises to a nominal fixed value. Operation at
this current may be used as a proxy for the presence of a syringe
in the machine. This may augment or supplant the photoelectric
syringe detection system for the interlock function.
[0036] A software interlock function can be applied as well. For
example the device could interrogate the user to confirm that a
syringe has been removed before plunger motion is unrestricted.
[0037] In FIG. 6, the input test conditions are keyed into the
device through the keyboard on the computer 2. This process permits
the calculation of the appropriate amount of contrast agent to be
pulled into the syringe. This data is passed to memory in process
20 if desired by the user. With the preliminary calculations
completed the filling device interrogates the holder to determine
if a syringe is present in process 2. If no syringe is present,
then an error condition is detected and the user is notified. It is
likely that this message will prompt the user to install the
correct syringe in process 24. Next, the device activates a
sterility interlock function in step 26 that creates error
conditions and messages if the syringe is removed before it is
completely filled according to the volume computed in step 13.
Next, the device issues the motor drive instruction to the plunger
in process 14. At the completion of the fill cycle the user removes
the syringe at process 28. The remaining processes return the
plunger to the start position for the next operating cycle. In this
preferred implementation the syringe detection is part of the
interlock process to eliminate operator error. A simpler, software
solution can be implemented as well. In this version the syringe
plunger motion aspirates contrast agent into the syringe and the
cycle will not resume until the operator has confirmed through a
keystroke on the console that the completed syringe has been
removed from the filling machine device.
[0038] In the embodiment shown in the figures, the input means of
the calculating portion 2 is shown as a keyboard. However, it is
within the scope of the present invention to use any other input
interface known in the art. For instance, it may be preferred in
some cases to transmit the data of the patient directly from the
host computer of the hospital into the calculating portion 2.
Alternatively, the interface of the calculating portion may be
simple selection switches.
[0039] Although it is not the main objective of the present
invention, the filling device of the present invention may be used
as an injector for pre-filled type syringes. In this case, although
a quantity of the chemical solution may be wasted, the injection
can be conducted easily.
[0040] The invention is not to be taken as limited to all of the
details set forth above, as modifications and variations to these
details may be made without departing from the spirit or scope of
the invention.
* * * * *