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`the unique advantage of permitting repeat perfu(cid:173)
`sion and blood flow studies in patients whose clini(cid:173)
`cal status is rapidly changing.
`Rubidium-82 is produced by the decay of its
`parent, strontium-82. E. R. Squibb and Sons, Inc.
`has developed a Rubidium-82 generator and infu(cid:173)
`sion system which yields an isotonic saline solution
`of Rubidium-82 at physiological pH for rapid ad(cid:173)
`ministration. ln animal experiments, the safety and
`myocardial uptake of Rubidium-82 has been dem(cid:173)
`onstrated. Therefore this agent has been selected
`as a candidate for clinical trials.
`In the Drawing:
`FIG. 1 is an overall schematic diagram of the
`strontium-rubidium infusion system used in con(cid:173)
`junction with the present invention;
`FIG. 2 is a front view of the infusion pump
`control used with the strontium-rubidium infusion
`system;
`FIG. 3 is a front view of the dosimetry con(cid:173)
`trol used with the strontium-rubidium infusion sys(cid:173)
`tem;
`
`FIG. 4 is a graph of radioactivity measured
`(on the y-axis) by the dosimeter probe versus time
`(on the x-axis);
`FIG. 5 is a perspective view of the dosimetry
`probe;
`FIG. 6 is a schematic diagram of the inter(cid:173)
`face between the dosimetry probe of FJG. 4 and
`the dosimetry control circuitry;
`FlG. 7 is a schematic diagram of the circuit
`for the Single Channel Analyzer used to convert
`and
`No. 156.285, entitled 82RB GENERATING METH(cid:173)
`OD AND ELUENT, filed on June 4, 1980 by Rudi
`D. Neirinckx, et al.
`
`Saline pumped through the strontium-rubidium
`generator 28 exits the generator 28 through tubing
`30 containing Rubidium-82. The tubing 30 is con(cid:173)
`nected to a diverter valve 32 having a first arm 34
`which leads through tubing 38, an antibacterial filter
`40, and ultimately to waste 42. A second arm 35 of
`the diverter valve 32 is connected through tubing
`44, an antibacterial filter 48, additional tubing 50,
`and into an infusion needle 52. The infusion needle
`52 is typically inserted into the arm 54 of a patient
`56.
`
`In the preferred embodiment of the invention,
`the check valve 16 is a dual back check valve of
`the type made by Beckton Dickenson Inc .. and the
`antibacterial filters are of the type made by Schlei(cid:173)
`cher & Schull as their type FP03013.
`ln the operation of the device, the amount of
`radioactivity in the saline eluted from the strontlum(cid:173)
`rubidium generator 28 must be measured as it is
`introduced
`into
`the patient 56. Accordingly. a
`dosimetry probe 58 is placed adjacent to the tub-
`
`ing 30 where it measures the radioactivity of the
`rubidium-containing saline as it leaves the gener(cid:173)
`ator 28 and enters the diverter valve 32.
`In order to use the infusion system, various
`procedures must be performed and controlled. In
`particular, the syringe 18 must be purged of air,
`and filled with saline, and the diverter valve 32
`must be positioned. These operations are contin(cid:173)
`gent upon a number of factors including the total
`volume to be infused into the patient 56, the total
`dosage to be infused into the patient 56, the mini(cid:173)
`mum radioactivity which must be present in the
`tubing 30 before any eluate is infused into the
`patient 56, the total volume to be infused {Note:
`The total volume eluted may differ from the total
`volume infused into the patient 56 as some volume
`is likely to be diverted to waste.)
`The foregoing parameters may be altered from
`the front panel of two different controllers shown in
`FIGS. 2 and 3. These are the infusion pump con(cid:173)
`troller 60 and the dosimetry controller 62. repec(cid:173)
`tively. The infusion pump controller 60 controls the
`mechanical movement of the syringe's plunger 66
`via a stepping motor 64 which is connected to the
`plunger 66.
`In the preferred embodiment of the invention.
`the syringe 18 is a sterile, disposable plastic sy(cid:173)
`ringe of the type made by Sherwood Medical and
`designated as Part. No. 881-514031. The infusion
`pump controller 60 limits the movement of the
`syringe plunger 66 based upon optical limit detec(cid:173)
`tors 68. 70 which limit the fully displaced and fully
`extended positions of the plunger 66, respectively.
`The volume control function performed by the infu-
`sion pump controller 60 is accomplished by count(cid:173)
`ing the number of pulses sent to the stepping
`motor 64.
`With reference to FIG. 2, the front panel of the
`infusion pump controller 60 is shown. The infusion
`pump controller 60 includes an on;off power switch
`72 which is used to turn on the power to the unit.
`A set of thumbwheel switches 74 is used to
`select the total volume (ml) to be eluted. An LED
`display 76 shows the total volume (ml) which has
`been eluted. A momentary contact push-button
`switch 78 is used to start and to stop the move(cid:173)
`ment of the plunger 66 in the forward (inject) direc(cid:173)
`tion.
`A set of push-button potentiometers comprise
`the Flow Rate Control 80 which is used to deter(cid:173)
`mine the volume per unit time which is infused.
`The Flow Rate Control 80 sets the pulse rate into
`the stepping motor 64. An LED 82 lights when the
`end of travel of the plunger 66, as indicated by the
`optical limit detectors 68, 70 is reached. A pair of
`momentary contact push-button switches 84, 86
`are used to control the purge and refill functions,
`respectively. of the syringe 18. Thus. if the purge
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`control switch 84 is pushed, and held, the plunger
`66 continues to move in the forward direction until
`it reaches the forward limit detector 68. Similarly,
`while the refill control switch 84 is pressed and
`held, the plunger 66 continues to move toward the
`rear limit detector 70. The speed of movement of
`the plunger 66 during purge and refill operatiQ[lS
`are controlled by adjustable screw-type potentiom(cid:173)
`eters 88, 90, respectively.
`The infusion pump controller 60 is comprised
`of a Superior Electric Company STM103 Translator
`Module which is interfaced to provide signals re(cid:173)
`presentative of flow rate. volume eluted. and injec(cid:173)
`tion. It is also interfaced to be remotely controlled.
`A pulse called "INIT" indicates that the Translator
`Module has been powered. The "INIT" pulse is
`used to reset the displays on the dosimetry mod(cid:173)
`ule. An "INJECT" signal indicates that the pump is
`injecting. Output pulses, corresponding to .1 ml
`steps of the syringe 18, are provided. An "End of
`Elution" signal is used to remotely disable the
`infusion pump controller 60.
`With reference now to FIG. 3, the dosimetry
`controller 62, is comprised of a number of LED
`displays and thumbwheel switch sets. In addition,
`includes an onroff
`the dosimetry controller 62
`switch 92 for providing power to the unit.
`The first set of thumbwheel switches 94 is
`used to set the volume (ml) to be infused into the
`patient 56. The LED display 96. immediately above
`the thumbwheel switches 94. displays the volume
`of eluate which has been infused into the patient
`56.
`
`The thurnbwheel switches 98 are used to set
`the total dose (rnCi) which is to be infused into the
`patent 56 and the LED display 100 immediately
`above the :otai dose thumbwheel switches 98 dis(cid:173)
`plays the total dose which has been infused into
`the patient 56. Similarly, the thumbwheel switches
`102 are used to set the dose rate (mCi sec.) which
`is to be used to determine when to switch the
`diverter va:ve 32 from the waste pos1t1on to the
`patient 56 position. The actual dose rate which rs
`present in the eluate within the tube 30 in front of
`the dosimetry probe 58 is displayed on the LED
`display 104. The descnotion of the dose present in
`the eluate at any given time from the start of
`infusion will be provided hereafter. The dosimetry
`controller 62 further comprises a pair of LED's 106.
`108 which indicate the pos1t1on of the d1verter valve
`32. On:y one of these two LED'S 106. 108. should
`be on at any given time.
`While the normai position of the diverter valve
`32 is toward waste. except when eluate 1s being
`infused into a patient 56. provision must be made
`to clear the tubing 44. 50 of any air prior to infusing
`a patient 56_ Accordingly, the cosimetry ccntro!!er
`62 includes a toggle switch 110 which is used to
`
`hard wire the diverter valve 32 in the patient 56
`position.
`The present preferred embodiment of the in(cid:173)
`vention also includes a set or thumbwheel switches
`112 which are used to set the flow rate which will
`be used in internal calculations of dosimetry con(cid:173)
`troller 62. It is presently anticipated by the inventor
`that a future version of the present mvention will
`include automatic means for determining the flow
`rate based upon the settings used in the infusion
`pump controller 60.
`Referring now to FIG. 4, a graph of the radioac(cid:173)
`tive dosage present in the tubing 30 in front of the
`dosimetry probe 58, is shown. In the graph, the
`dosage is measured on the y-axis and time is
`measured on the x-axis. The time is referenced
`with zero being the time that the start:stop inject
`button 78 on the infusion controller 60 is pushed to
`commence infusion.
`For approximately 10 seconds there will be no
`in
`the eluate
`from
`the
`radioactivity present
`strontium-rubidium generator 28. Thereafter.
`the
`dose rate rises at a rapid rate up to a maximum.
`after which the dose rate falls to a level value
`indicative of the steady state regeneration rate of
`the Sr-Rb generator 28. Thus. when the infusion
`starts, there is a delay initially as the dose rate
`builds up, a reduction in dosage after the generator
`28 is partially eluted, and then there is a dosage
`representative of the steady state regeneration rate
`of the generator 28.
`thumbwheel
`the dose rate
`The setting of
`switches 1 02 tells the dosimetry controller 62 at
`what point along the upward slope of the dosage
`curve to switch the diverter valve 32 from the waste
`position to the patient 56 position whereby the
`eluate will be infused into the patient 56. At that
`point the dose indicated by the LED's 100 will start
`accumulating from zero. where it had been until
`that point. Similarly. the patient 56 volume indi(cid:173)
`cated by the LED's 96 will start to accumulate as of
`that time.
`Once eluate is infused into the patient 56. it
`continues to be infused until one of various stop
`indications occurs. In particular. when the total pa(cid:173)
`tient 56 dose. set by the thumbwheel switches 98,
`is reached, the diverter valve 32 is returned to the
`waste position. and the stepping motor 64 stops.
`thereby preventing further infusion. Similarly. the
`diverter valve 32 is switched, and the stepping
`motor 64 is stopped when the patient 56 volume.
`preset by the thumbwheel switches 94 reaches its
`preset value or after the total volume to be eluted.
`the volume
`thurnbwheel switches 74
`set by
`reaches its preset value: or when the purge limit
`optical stop 68 of the syringe 18 is reached: or if
`:he start stop in1ect button 78 is pushed. Any of the
`foregoing events causes the diverter va,ve 32 to
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`switch to the waste position, and causes the step(cid:173)
`ping motor 64 to stop. Note, however. that the
`purge and refill switches 84, 86 are disabled as of
`the time that the starttstop inject button 78 is
`pushed to commence the infusion.
`
`Quantizing Radioactivity in ~ Liquid Stream
`
`In order to measure the radioactivity in the
`saline solution which passes through the line 30 in
`front of the dosimetry probe 58, it is necessary to
`count the number of disintigrations which occur in
`front of the probe 58, while at the same time
`keeping track of the flow rate of the saline through
`the tube 30. Given that these quantities are known,
`it is possible to measure the total activity in mil(cid:173)
`liCuries (mCi) in accordance with the following for(cid:173)
`mula:
`
`A = (V) (E) (CM} (Y)
`
`{C) (F)
`
`Where. A = total activity (mCi);
`C = net counts;
`F = flow rate (ml;min);
`V = volume in detector view (ml);
`=
`E
`net
`efficiency
`minute:disintegration per minute);
`CM = disintegrations/minute to milliCurie conver(cid:173)
`sion factor; and
`Y = net yield of photon.
`In the case of the present invention. the above
`formula can be simplified to:
`
`(counts
`
`per
`
`A
`
`(Cl ( F)
`K
`
`Where. A = total activity (in milliCuries);
`C = net counts (from probe);
`F = the flow rate; and
`K :::; the calibration factor.
`As noted, the calibration factor. K. takes into
`account the volume in the detector's view. the net
`efficiency of the probe. the conversion factor in
`terms of disintigrations pet minute to milliCuries,
`and the net yield of photons. These factors are
`substantially constant for any given probe and tub(cid:173)
`ing combination for a reasonable amount of time.
`Accordingly, provision is made on the circuit board
`to adjust the calibration factor. K, when the instru(cid:173)
`ment is serviced. However. the calibration factor. K.
`1s not user adjustable in
`the normal course of
`
`operation.
`
`Dosimetry Probe
`
`Referring now to FIG. 5, the dosimetry probe
`58 is comprised of a photomultiplier tube 120, such
`as the RCA C83009E 14 mm diameter 10-stage
`photomultiplier tube manufactured by the Electro
`Optics Division of RCA Corporation in Lancaster.
`Pennsylvania. The photomultiplier tube 120 has a
`face 122 through which input signals in the form of
`light are received. On the face 122, a plastic scintil-
`lator 124, such as a Nuclear Enterprises Type
`102A manufactured
`in Edinburgh, Scotland,
`is
`mounted. In the preferred embodiment of the in(cid:173)
`vention, the plastic scintillator 124 is glued or bon(cid:173)
`ded to the face 122 of the photomultip!ier tube 120.
`After the plastic scintillator 124 has been bonded to
`the face 122 of the photomultiplier tube 120, an
`aluminum foil covering (not shown) is placed over
`the face end of the photomultiplier tube 120, in-.
`eluding the plastic scintillator 124. The purpose of
`the aluminum foil covering is to reflect back into
`the tube 120 any light which scintillates from the
`plastic scintillator 124 away from the tube 120. In
`addition, the aluminum foil covering prevents any
`stray light which might come into the area of the
`face 122 from getting into the tube 120. Following
`the application of the aluminum toil, a light tight
`material, such as black electrical tape is wrapped
`over the aluminum foil covered tube 120 in order to
`further prevent any light from entering into the tube
`120. The tape-wrapped tube 120 is then inserted
`into a mu metal shield 126 which is intended to
`prevent any electromagnetic radiation effects from
`affecting the output of the dosimetry probe 58. In
`the preferred embodiment of the invention, the
`dosimetry probe 58 is plugged into a standard
`photomultiplier tube socket base 128 containing a
`standard resistive biasing network.
`
`Dosimetry Circuitry
`
`Referring now to FIG. 6, the photomultiplier
`tube socket base 128 includes a resistive network
`containing biasing resistors for placing appropriate
`bias voltages on the ten dynodes in the photomul(cid:173)
`tiplier tube 120. Accordingly, the high voltage con(cid:173)
`nection to the photomultiplier tube base 128 is
`automatically biased to provide appropriate operat-
`ing voltages to the photomultiplier tube 120. The
`high voltage supply 130 used
`in
`the preferred
`embodiment of the invention is a 0-1000 volt, ad(cid:173)
`justable Bertan PMT-10A-P power supply manufac-
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`tured by 8ertan Associates, Inc., Three Aerial Way,
`Syosset, New York. In the present application, the
`high voltage supply 130 is adjusted to provide an
`output voltage of 950 volts. The photornultipler tube
`socket base 128 is an RCA photomultipler tube
`socket base, part No. AJ2273.
`the dosimetry
`from
`An output signal goes
`probe 58 on a line 132 to a coupling network
`comprising a pull up resistor 134, a coupling ca(cid:173)
`pacitor 136, and a output resistor 138. Accordingly.
`an AC signal having a peak to peak maximum of
`approximateiy 250 millivolts with negative going
`pulses, is provided on output line 140.
`
`Single Channel Analyzer
`
`Referring now to FIG. 7, the schematic diagram
`for a Single Channel Analyzer circuit is shown. The
`Single Channel Analyzer is used, because
`the
`pulses on output line 140 from the Dosimetry cir(cid:173)
`cuitry are very sharply defined pulses which may
`occur at very high frequencies. In view of the fact
`that it is important to count all the pulses. a very
`high speed comparator. such as an AM685 voltage
`comparator 142, manufactured by Advanced Micro
`Devices, 901 Thompson Place. Sunnyvale. Califor(cid:173)
`nia. with emitter-coupled
`logic (EGL) output. or
`other suitable very high speed comparator, must
`be used_
`A biasing network 141 consisting of a series of
`resistors and capacitors is used as one input to the
`comparator 142. In view of the fact that the pulses
`which are handled by the comparator 142 are of
`very short duration. a one-shot circuit 144. com(cid:173)
`prised in the preferred embodiment of the inven(cid:173)
`tion. of a Motorola Type 1670 master-slave flip-flop
`integrated circuit. is used to stretch the pulse width
`up to a uniform pulse width of approximately 50
`nanoseconds. The output signal from the one-shot
`144 is fed into a programmable divide-by-N circuit
`146. which in the preferred embodiment of the
`invention is comprised of a Motorola Type 10136
`universal hexadecimal counter integrated circuit.
`The divide-by-N circuit 146 is programmable. Ac(cid:173)
`cordingly. a very high pulse repetition rate coming
`into the comparator with very short pulse widths is
`reformed by the one-shot to have wider. uniform
`pulses. and the mput signal is further reformed by
`the divide-by-N circuit to bnng the puise repetition
`rate dcwn into any desirable range. ln particular.
`outputs of the divide-by-N circuit 146 are provided
`for N equal to 2. 4. 8. and 16.
`Up through this point in the circuit the devices
`have all been of ECL type in order to be able to
`handle the very high speed pulses which are de(cid:173)
`tected by the dcsrmetry prcce 58. In view af the
`
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`that
`fact
`transistor(cid:173)
`to use
`is conventional
`it
`transistor-logic (TTL)
`integrated circuits. a
`type
`10125 ECL-to-TTL level converter circuit 150 is
`hooked to the output of the div1de-by-N circuit 146.
`Thus, the ECL-to-TTL level converter circuit 150
`transforms the ECL signal levels into TTL signal
`for
`further processing. The TTL outputs
`levels
`leave the EGL-to-TTL level converter circuit 150 on
`four lines 152, 154, 156, 158, which correspond to
`the TTL level of the counts into the Single Channel
`Analyzer divided by 2. 4, 8. and 16, respectively.
`The counts out on the lines 152-158 will be re(cid:173)
`ferred to hereafter as the "net counts".
`
`Multiplier-Divider Circuit
`
`Referring now to FIG. 8, there is a Multiplier-
`Divider circuit 160 which converts the net counts
`from the Single Channel Analyzer circuit, described
`above. into a meaningful quantity (milliCuries). The
`Multiplier-Divider circuit 160 accepts
`the
`"net
`counts" on an input line 162 which is connected to
`one of the lines 152-158 from the Single Channel
`Analyzer (i.e., the raw counts converted into TTL
`levels. and then divided by 2. 4, 8, or 16) and
`multiplies them by the eluate Flow Rate divided by
`100. The result is then divided by a constant. K, in
`order to carry out the formula:
`
`nn <Fl
`A.,.. K
`
`Where. A = total activity (in m1lliCunes):
`N = net counts (from Single Channel Analyzer):
`F = Flow Rate: and
`K = the calibration factor.
`The net counts. N. are first multiolied by a two
`digit number corresponding to the eluate Flow Rate
`(entered on the Flow Rate thumbwheel switches
`112A. 1128. corresponding to the most significant
`digit (MSD) and the least significant digit (LSD),
`respectively. the thumbwheel switches 112A. 1128
`are on the front panel of tt~e dosimetry controller
`62. shown 1n F!G. 3. The multiplication is accom(cid:173)
`plished by cascading two TTL Synchronous Dec(cid:173)
`ade Rate Multiplier circuits (F74167). and sending
`their outputs through a NANO gate 168. The result(cid:173)
`ing output corresponds to Fout· where:
`
`Fout
`
`(N)(F)
`= 100
`
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`The output pulses are of varying duration, so
`they are next fed through a pair of one-shots which
`process them
`to have a fixed duration.
`In
`the
`preferred embodiment of the invention, the first
`one-shot is comprised of one-half of an SN74123
`integrated circuit 170. The first one-shot is negative
`edge triggered, and it provides a pulse output of
`approximately 200 nano"seconds. Its output is dou(cid:173)
`ble buffered through buffers 172, 174 into a second
`one-shot which
`is comprised of one-half of a
`CD4098BE integrated circuit 176 in order to in(cid:173)
`crease the width of the output pulses, so they will
`be acceptable to a CMOS divider integrated circuit
`178. The second one-shot is configured to be lead(cid:173)
`ing edge triggered.
`The output of the second one-shot is then
`divided by the calibration factor, K, which may
`have a range of between 3 and 9,999. A C04059A
`integrated circuit 178 is used as a programmable
`divide-by-N counter. Programming is accomplished
`via a series of 16 DIP switches 180 mounted on the
`printed circuit card. Each set of four switches cor(cid:173)
`responds to the BCD settings for 1 's, 1 O's, 1 OO's
`and 1000's. Pull up resistors (not shown) are em(cid:173)
`ployed in the standard manner so that when the
`DIP switches are open the inputs to the divide-by(cid:173)
`N circuit 178 are pulled high.
`The output of the divider 178 has pulses of
`random widths, so another one-shot. made up of
`the second half of the C04098BE 176 configured
`for leading edge triggering, is used. This one-shot
`provides an output pulse duration of approximately
`20 microseconds. Before leaving the Multiplier-Di(cid:173)
`vider circuit 160, the output is double buffered
`through buffers 182, 184 and the output signal on
`line 186 is sent to the Dose Rate circuit. There will
`be one dose corrected output pulse on line 186 for
`each 0.01 milliCurie of activity which passes by the
`dosimetry probe 58.
`
`Display Controller Circuit
`
`Referring now to FIG. 9, the schematic diagram
`for a Display Controller Circuit 190 is shown. There
`are
`three Display Controller Circuits within
`the
`dosimetry controller 62. Each Display Controller
`190 is used both to interface a set of thumbwheel
`switches 192 and to display the quantity associated
`with the particular set of thumbwheel switches 192.
`Thus, there is one Display Controller of 190 for
`Dose Rate (which works with thumbwhee! switches
`102 and LEDs 104), one for Patient Volume (which
`works with thumbwheel switches 94 and LEDs 96),
`and one for Dose (which works with thumbwheel
`switches 98 and LEDs 100). Each Display Control(cid:173)
`ler Circuit 190 drives four seven-segment displays
`
`194, such as MAN71 displays.
`The major component of the Display Controller
`Circuit 190 of the preferred embodiment of the
`invention is an lntersil ICM72171JI integrated circuit
`196, which is a device which provides a direct
`interface to the seven-segment displays 194. Each
`Display Controller Circuit 190 allows the user to set
`a level, by programming binary coded decimal
`(BCD) thumbwheel switches 192. The levels can
`then be detected. In this way, a preset limit for
`Dose, for example, will be detected and will be
`used to shut down the infusion pump. For Dose
`Rate, the preset level is used to switch the position
`of the diverter valve 32, through the valve driver
`circuit which will be explained hereinafter. The Pa(cid:173)
`tient Volume can also be preset, and the infusion
`pump can be stopped at the preset limit.
`
`Dose Rate Circuit
`
`The Dose Rate circuit 200, shown in FIG. 10,
`provides a visual display of the amount of radiation
`present in the eluate. The Dose Rate circuit 200
`employs a Display Controller Circuit, of the type
`described above. The Dose Rate display is con(cid:173)
`stantly updated to provide the user with Dose Rate
`information. The Dose Rate circuit 200, with the
`Display Controller, is programmed to set a trigger
`level for switching the eluate from waste to the
`patient 56.
`The Dose Rate circuit 200 uses signals from
`the Multiplier-Divider circuit 160, described above,
`and from the Control Board which will be described
`hereinafter. The dose corrected output pulses on
`line 186 from the Multiplier-Divider circuit 160 de(cid:173)
`scribed above (i.e., 1 pulset.01.'mCi) enter the Dose
`Rate circuit 200, and are double buffered by buff-
`ers 202, 204. The buffered pulses are then fed
`through one-half of a one-shot 206, comprised of a
`CD4098BE integrated circuit in the preferred em(cid:173)
`bodiment of the invention. The output from the
`one-shot 206 is gated through NANO gate 207 to
`the Dose Rate Display 104 since there are three
`Display Controller Circuits 190, which are used for
`Dose {circuit "A"), Dose Rate (circuit "B"), and
`Patient Volume (circuit "C"), the designation "810"
`at the output of NAN D gate 207 means pin 10 on
`input connector 197 (see FIG. 9).
`The heart of the Dose Rate circuit 200 is an
`lntersil ICM7207A Oscillator Controller integrated
`circuit 208. This unit, along with a dual one-shot
`comprised of a CD40988E integrated circuit 210. in
`the preferred embodiment of the invention, pro(cid:173)
`vides all of the control necessary for gating, stor(cid:173)
`ing, and resetting the display.
`The outputs of the Dose Rate Display Control-
`
`5
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`10
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`15
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`13
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`EP 0 310 148 A2
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`14
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`s
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`10
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`circuit 230 accepts its input from the Dose Rate
`circuit or from the Patient Line Purge Switch 110.
`The Patient Line Purge Switch 110 directly controls
`the valve 32.
`The diverter valve 32 is a two position valve
`which includes electrical switches which close in(cid:173)
`dividually when the valve 32 is fully in either the
`patient or waste position. Movement of the valve 32
`from one position to the other is controlled by an
`AC motor which includes two windings allowing it
`to be moved in either direction via an AC motor
`having two windings. When the first winding is
`energized. the motor moves in a clockwise direc(cid:173)
`tion. When the second winding is energized. the
`15 motor moves 1n a counterclockwise direction. At
`each limit of the valve movement. there is a micro(cid:173)
`switch 232, 234 which senses when the valve limit
`has been reached.
`When one of the microswitches 232, 234 is
`open. i.e. switch 232, the input to an associated
`inverter 236 is essentially at ground. When the
`switch 232 closes. the input to the inverter 236
`increases to approximately
`five volts. After the
`switch 232 again opens. it takes some time, due to
`the RC time constant of the associated resistors
`and capacitor. before the voltage at the input of the
`first inverter 236 returns
`to approximately zero.
`Accordingly, the combination of inverters and the
`RC network to which each of the switches 232, 234
`are connected acts as a switch debouncer. Thus,
`the output of inverter 238 will be low when switch
`232 is closed and high when switch 232 is opened.
`Similarly, the output of inverter 240 will be low
`when switch 234 is closed and high when switch
`234 is opened.
`NANO gate 242 normaily has a high output
`voltage. Accordingly. as will be obvious to those of
`ordinary skill in the digital circuitry art, LED 106 will
`be on when switch 232 is closed. Otherwise. LED
`106 will be off. Similarly, LED 108 will be on when
`switch 234 is closed. Note that these LEDs 106,
`108 were previously described with reference to
`the dosimetry controller 62 (See FIG. 3).
`When both switches 232. 234 are opened at
`the same t;me. there will be two high signals at the
`input of NANO gate 254. That will cause NANO
`gate 256 to trigger a monostable multivibrator com(cid:173)
`prised of one half of a CD4098BE integrated circuit
`258 wh1cn provides a low going output pulse hav-
`50 mg a duration oi aoprox1mately 700 milliseconds in
`the preferred embodiment of the invention. The
`particular time period during which this pulse is low
`must exceed the time period which it would take
`for the diverter valve 32 to be moved from one
`position to the other pos1t1on. In the preferred em(cid:173)
`bodiment of the invention the movement of the
`diverter vaive 32 takes approximately 600 millisec(cid:173)
`onds The outputs from the monostable mult1v1bra-
`
`ler Circuit provide an easy interface to determine
`when a predetermined count (corresponding to the
`dose rate which was set on thumbwheel switches
`102) has been reached. and to generate a signal
`which is used for switching the diverter valve 32.
`The valve switching signal is also used to enable
`the Dose and Patient Volume Displays. 100, 96,
`respectively.
`In the preferred embodiment of the invention,
`the valve switching signal is derived from one half
`of a dual 0-type flip-flop, such as a CD4013BE
`integrated circuit 212. The flip-flop 212 is only
`enabled during an injection. i.e .. when the infusion
`pump is being used to either infuse eluate into a
`patient 56 or to divert it to waste. The enabling
`"INJECT" signal is generated when the pump is
`injecting. Once an injection is started and a user
`pre-set Dose Rate limit set on thumbwheel switch(cid:173)
`es 102 is met. the flip-flop 212 latches a positive Q
`output to switch the diverter valve 32 from the
`waste position to the patient position and to enable
`the Dose Display and the Patient Volume Display.
`
`Control Circuit
`
`Referring now to FIG. 11, the schematic dia(cid:173)
`gram of the Control circuit 220 is shown. The
`purpose of the Control circuit 220 is to "oversee"
`all other operations. Specifically. the Control circuit
`220 controls the Dose Display and Patient Volume
`Display. The Control circuit 220 also provides tim(cid:173)
`ing for resetting the Multiplier-Divider circuit 160.
`and it buffers various inputs and outputs to and
`from the infusion pump control module 60.
`infusion
`The basic
`function
`for
`turning the
`pump off is the End of Elution signal. The End of
`Elution signal is derived from either the Dose Dis(cid:173)
`play 100 or the Patient Volume Display 96. These
`displays 100. 96 are gated to begin coLmting once
`the Dose Rate trigger level. the Q output from flip(cid:173)
`flop 212. reaches its preset limit. as defined by the
`Dose Rate thurnbwheel switches 1 02. Then. once
`the Dose or Patient Volume is met. as defined by
`the Dose thumbwheel switches 98 and by the
`Patient Volume thumbwheel switches 94. respec(cid:173)
`fr1ely. the Control circuit 220 signals the pump to
`stop.
`
`Valve Driver Circuit
`
`The Vaive Driver circuit 230. shown schemati(cid:173)
`cally :n FIG. 12. •S used to control the switching of
`the c1verter ·1al'/8 32 which directs the eluate either
`to the nat1ent 56 or to waste. The Valve Driver
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`15
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`EP 0 310 148 A2
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`tor are fed via EXCLUSIVE OR gate 260 into a 0-
`type flip-flop 262 comprised of a CD4013BE in·
`tegrated circuit. In the event that the diverter valve
`32 did not move from one position to the other
`within the prescribed time period, it is presumed
`that a fault condition occurred, e.g. the diverter
`valve 32 jammed. Accordingly, the operator is ad(cid:173)
`vised of the fault condition by both LEDs 106, 108
`flashing simultaneously. The flashing occurs as a
`result of the output of the flip-flop 262 which is
`connected on line 264 to NANO gate 242 being
`kept high, thereby causing NANO gate 242 to act
`as an astable multivibrator which oscillates between
`high and low outputs thereby causing the EXCLU(cid:173)
`SIVE OR gates 248, 250 to change states and to
`flash the LEDs 106, 108.
`At the same time that one output of the flip-flop
`262 goes high, the other output. on line 266 goes
`low. The signal on line 266 is normally high, as it is
`one input to NANO gate 268. The other input to
`NANO gate 268 is the "End of Elution" signal
`previously discussed. When both inputs to NANO
`gate 268 are high the output on line 270 is high.
`The output signal on line 270 turns off the infusion
`pump w