JPH0252671A - Radioactive gas inhalator - Google Patents

Abstract

PURPOSE:To improve a check accuracy by switch-controlling respective electromagnetic valves in synchronizing to actions to breathe out and, next, to inhale of a subject at the time of a changeover from a standby mode to a mode to inhale a mixed gas. CONSTITUTION:The subject mounts a mask 9, and the standby mode is in. At such a time, an electromagnetic valve 27 between a closing circuit and it is closed, an electromagnetic valve 26 between an outside air and it is opened, and the subject can freely execute an outside air respiration. Next, the electromagnetic valve 26 is closed, simultaneously, the electromagnetic valve 27 is opened, and the changeover from the outside air respiration to a mixed gas respiration to contain a xenon gass is executed. On the other hand, a flow sensor 10 is provided to a guide pipe 8 for a mask, the timing of the respiration of the subject is detected, the electromagnetic valves 26 and 27 are operated in synchronizing to the actions to breathe out and, next, inhale of the subject by the detecting signal, and an automatic control is executed to switch the circuit. Thus, an exhalation added to the mixed gas hardly exists, and consequently, the concentration lowering of the xenon gas is hardly generated. Consequently, the accuracy of the check can be increased.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is useful for administering radioactive gas such as xenon gas (L33Xe gas) into the body to perform pulmonary function tests, cerebral blood flow measurements, etc. This relates to the radioactive gas inhalation device used.

(Prior art) Conventionally, this type of device creates a mixed gas of radioactive gas and oxygen gas in a fixed ratio in advance in a closed circuit, and connects this closed circuit with a mask worn by a subject. The radioactive material is taken into the body by communicating with the patient and breathing the mixed gas. After the test, the radioactive materials taken into the body are removed from the body.
What is called washing out is performed, and the extracted radioactive materials are ultimately captured and recovered so that they are not released into the atmosphere.

(Problems to be Solved by the Invention) However, the conventional device has the following deficiencies.

(b) Prior to the subject inhaling the mixed gas.

First, there is a standby mode where you breathe outside air while wearing a mask, and at a certain point you switch from breathing outside air to mixed gas breathing, but because this was a manual switch, the switching point was not constant. For example, if the subject inhales and then switches at the moment when he is about to exhale, the subject's exhalation will be added to the gas mixture, which will cause the concentration of the gas mixture in the closed circuit to fluctuate significantly. , and the accuracy of the test decreases.

(b) The closed circuit has an expandable bellows that contracts when the subject inhales and expands when the subject exhales. During repeated breathing, oxygen is consumed and the amount of gas decreases. On the other hand, due to differences in lung capacity depending on the subject, the amount of gas within the bellows may be insufficient or too large, in which case breathing becomes difficult.

Conventionally, such cases were detected, a warning was issued by a buzzer, etc., and measures such as oxygen gas replenishment were taken, which resulted in a problem that the measures were delayed.

(c) Depending on the testing method, there is a so-called bolus (bulk) inhalation method in which only a lump of gas is inhaled all at once. Previously, the required amount of gas had to be manually brought to the subject's mouth and set, which risked exposing the operator to radiation, and the use of a relatively large internal diameter conduit. Since the radioactive gas was administered to the subject through the tube, there was a problem in that the concentration of the radioactive gas was likely to change due to the accumulated gas inside the tube.

(d) After the test is completed, it is necessary to clean the inside of the closed circuit as well as wash out the radioactive material from the subject's body. The contaminated gas containing these radioactive substances was drawn by a pump and exhausted through a radioactive substance trap, but the pump was operated continuously.

Therefore, there was a problem that the life of the trap was shortened.

(e) The electric arm that holds the mask section rotates and positions itself according to the position of the patient's face. There was a risk of hitting someone and causing injury or damage to property.

The present invention was made in order to solve the above conventional problems, and is a radioactive gas inhaler that improves various defects, increases inspection accuracy, improves safety, and extends the life of the device. The purpose is to provide

(Means for solving the problem) In order to achieve the above objective, (1) To solve the above problem (a), close the solenoid valve connecting the closed circuit conduit and the mask conduit, and connect the closed circuit conduit with the outside air. When switching from the standby mode in which the general solenoid valve is opened and the subject breathes outside air to the mode in which the solenoid valve connected to the conduit is opened and the solenoid valve for communicating with outside air is closed to inhale the mixed gas, A control means is provided for switching and controlling each electromagnetic valve in synchronization with the action of the examiner exhaling and then inhaling.

(2) Regarding problem (b), in the mixed gas suction mode, when the mixed gas contained in the bellows becomes less than the predetermined first volume, a predetermined amount of oxygen gas is automatically inhaled. and, conversely, when the mixed gas reaches a predetermined second capacity or more, a predetermined amount of the mixed gas is automatically exhausted, and furthermore, when the mixed gas in the bellows remains almost zero for a predetermined period of time, and When the mixed gas remains substantially full for a predetermined period of time, the solenoid valve connected to the conduit closes, the solenoid valve for communication with outside air opens, and control means is provided for switching to the outside air breathing state.

(3) Regarding problem (c), the oxygen gas source, the radioactive gas source, and the mask conduit are equipped with a thin tube that communicates with each other, and during the bolus inhalation test, a predetermined amount of radioactive gas is pumped into the mask at oxygen gas pressure. A bolus inhalation mechanism is provided that instantly transfers the bolus to the mouth.

(4) Also, regarding problem (d), before the radioactive material trap in the exhaust system, a container for temporarily storing exhaust gas and a means for detecting the amount of exhaust gas in this container is provided. A means is provided to operate an exhaust pump to exhaust the gas in the container when the amount of exhaust gas in the container exceeds a predetermined amount.

(5) Further, to address the problem (e), a safety switch mechanism is installed on the electric arm and closes the contact when it comes into contact with a human body or an object, thereby stopping the rotation of the electric arm.

(Function) According to the configuration (1) above, since the switching occurs at the moment the subject takes a breath, fluctuations in the radioactive gas concentration within the closed circuit are extremely small, and therefore the accuracy of the test is high.

According to configuration (2), oxygen gas is replenished in response to a drop in oxygen concentration, and in an emergency, breathing is switched to outside air, so there is no fear that the subject will feel short of breath. .

According to configuration (3), there is no need for manual intervention, which eliminates the risk of the operator being exposed to radiation.Moreover, since the gas is transferred inside the tube, the amount of gas accumulated in the tube is negligible, so there is no change in the concentration of radioactive gas. Less is.

Furthermore, according to configuration (4), the exhaust pump rotates only when a predetermined amount of exhaust gas has accumulated in the container, so the time required for exhaust gas containing radioactive gas to pass through the trap is significantly reduced, and as a result, Extends trap life. If the exhaust pump is constantly rotating and pulling, a gas flow will occur around the subject's mouth, placing a burden on breathing, but this burden is relieved.

Furthermore, according to configuration (5), even if the electrically rotating arm hits a person or property, the safety switch will immediately stop the arm, thereby preventing injury or property damage. , safety is increased.

(Example) Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.

1 is a telescopic bellows, 2 is a series of conduits with an inlet and an outlet connected to the bellows 1, 21.22.23°24
and 25 are electromagnetic valves; 3 is a means for removing carbon dioxide, such as soda lime; and 4 is a conduit 2 for transporting the gas contained in the bellows 1.
5 is a blower used to forcibly take in outside air; 6 is a one-way valve as an outside air intake via a solenoid valve 21; 7 is a one-way valve as an outlet; These constitute a closed circuit.

8 has one end connected to the conduit 2 via a solenoid valve 27,
It is a mask conduit having an electromagnetic valve 26 for communication with the outside air, and a mask 9 worn by the subject at the other end, and also includes a flow sensor 10 for detecting the flow of gas within the tube.

28 to 37 are electromagnetic valves arranged in the gas pipes, and 41 to 44 are pumps. Also, 11
12 is an oxygen gas cylinder, 12 is a xenon gas source, 13 is a Douglas bag for temporarily storing exhaust gas, 14 is silica gel, 15 is for capturing and recovering radioactive substances in exhaust gas,
For example, traps such as charcoal.

Further, 16 and I7 are scintillation detectors that detect the intensity of radioactivity contained in the gas, and 16 is placed in the conduit 2, and 17 is a scintillation detector that detects the radioactivity of the gas sampled from the bellows 1 and the mask conduit 8. To detect. 20 is a preamplifier that amplifies the detection signal of the scintillation detector 17. Furthermore, a gas analyzer 18 is connected to detect the 02 concentration and CO2a degree in the gas sampled from the mask conduit 8. 19 is a gas flow meter.

Next, the operation of this embodiment and the specific configuration of the invention will be explained. First, in a closed circuit consisting of the bellows 1, conduit 2, etc., a mixed gas of xenon gas and oxygen gas of a required concentration is created. in this case.

In the closed circuit, the solenoid valves 21, 23, 25 and 27 are closed to cut off the outside air, and the oxygen gas cylinder 11. Solenoid valve 3
0, xenon gas source 12. A predetermined amount of oxygen gas and xenon gas are introduced through the route of the solenoid valve 32. Then, the blower 4 is operated to circulate the gas in the closed circuit in the direction of the arrow. In this embodiment, the bellows 1 having a maximum volume of 8Q is used.

The subject puts on the mask 9 and enters standby mode.

At this time, the solenoid valve 27 between the closed circuit and the outside air is closed, and the solenoid valve 26 between the closed circuit and the outside air is open, and the subject can freely breathe outside air.

Next, the solenoid valve 26 is closed and the solenoid valve 27 is opened to switch from breathing the outside air to breathing a mixed gas containing xenon gas. Conventionally, this switching has been performed manually by the operator. However, in the case of manual operation, the switching point is not constant, so for example, when the patient's breath is added to the mixed gas,
For this reason, the concentration of xenon gas adjusted in advance decreases,
The accuracy of the test could also be affected. Therefore, in this embodiment, a flow sensor 10 is provided in the mask conduit 8 to detect the timing of the subject's breathing, and based on this detection signal,
The electromagnetic valves 26 and 27 are operated in synchronization with the subject's exhalation and subsequent inhalation, and the circuit is automatically controlled to switch. As a result, almost no exhaled air is added to the mixed gas, and therefore the concentration of xenon gas hardly decreases. Note that as the flow sensor, pressure type, thermal type, and other types of detectors can be used.

When switched to the mixed gas inhalation mode, the bellows 1. Solenoid valve 22. The gas flowing in the direction of the arrow into the conduit 2 is used as intake air into the mask conduit 8. mask 9
The exhaled air is inhaled into the subject's lungs through the mask 9.
．． From mask conduit 8 to conduit 2. fri magnetic valve 24. It flows to bellows 1 via soda lime 3 and blower 4.

Co2 contained in exhaled breath is adsorbed and removed by soda lime 3.

In this embodiment, the circulating airflow is formed by the blower 4 in the closed circuit, so the inhalation side and the exhalation side are completely separated in the conduit 2, and the flow does not place any burden on the subject's breathing. You can breathe freely without any pressure. Conventionally, in order to separate the inhalation side and the exhalation side, one-way valves have been disposed in each conduit, which also poses the problem of placing a burden on breathing.

In this mixed gas inhalation mode, the bellows 1 expands and contracts in response to the subject's breathing. In other words, when the subject breathes in, it contracts, and when they breathe out, it expands. Therefore, during repeated breathing, oxygen is consumed and the amount of gas decreases, and on the other hand, due to reasons such as differences in lung capacity depending on the subject, the amount of gas in the bellows may be insufficient or too large. Sometimes, breathing becomes difficult. In this embodiment, the maximum volume of the bellows 1 is set to 8Q, but when it contracts and reaches IQ, the solenoid valve 28 opens and a predetermined amount of 0° gas is supplied, reducing the oxygen concentration and increasing the volume of the bellows 1.
prevent the volume from decreasing. Conversely, when the bellows expands and its volume exceeds 7Ω, the electromagnetic valve 34 opens and the pump 44 evacuates a predetermined amount, thereby preventing the bellows from becoming full. Further, when the gas amount in the bellows 1 remains at almost OQ for 2 seconds, or when the gas amount remains almost full for 2 seconds, the solenoid valve 27 is closed and the solenoid valve 26 is closed.
Open it and instantly switch to breathing outside air. In this way, safe breathing of the subject is ensured.

As mentioned above, in addition to the method of introducing radioactive material into the body by breathing a gas mixture in a closed circuit, there is a method of bolus inhalation. This is a single inhalation of a bulk gas mixture, in which case the required amount of gas is provided via a route other than the closed circuit. Previously, the device had to be manually brought up to the subject's mouth and set, making it unavoidable to expose the patient to radiation. In this embodiment, from the oxygen gas cylinder 11 to the solenoid valve 30. Xenon gas source 12. A narrow tube route is provided that passes through the solenoid valve 33 and reaches the mask conduit 8. When the required amount of gas is set in the xenon gas source 12 and a bolus switch (not shown) is pressed, the pressure in the oxygen gas cylinder 11 is applied, instantly Xenon gas is sent as a bolus to the vicinity of the mask. In this way, this example does not require any manual labor, so there is no need to worry about radiation exposure.Furthermore, since a thin tube is used, there is very little accumulated gas, and there is little change in the concentration of radioactive gas, making it efficient. , it becomes possible to perform highly accurate inspections.

After the test is completed, it is necessary to clean the inside of the closed circuit and expel the radioactive material introduced into the subject's body, which is called washing out. First, when washing out, close the closed circuit solenoid valve 22, 2/l and
and the bellows 1, and open the solenoid valves 21 and 25. The subject takes in outside air as inhalation through the one-way valve 6 and exhales air through the one-way valve 7. By repeating this a predetermined number of times, the radioactive materials in the body are expelled. On the other hand, the exhaust gas discharged through the valve 7 is first stored in the Douglas bag 13, and when the amount of exhaust gas in the bag exceeds a predetermined amount, the pump 41 starts rotating, and the exhaust gas is discharged to the outside through the silica gel 14 and the trap 15. be discharged. Radioactive substances contained in the exhaust gas are captured and recovered by the trap 15. When the amount of exhaust gas in the bag 13 falls below a separately determined amount, the pump 41 stops rotating.

As an example of such a means, for example, as shown in FIG. 2, expansion and contraction of the bag 13 may be detected by an actuator 46 of a switch 45, and the pump 41 may be controlled by operating the switch.

In this way, in this embodiment, the exhaust pump operates only when the amount of exhaust gas accumulates above a certain level, so compared to the conventional case where it operated continuously, the exhaust gas is reduced. The time taken to pass through the trap 15 will be significantly reduced, extending the lifetime of the trap. Also, pump 4
When 1 is in operation, a load is placed on the subject's breathing, making it difficult to breathe, but as in this example, the pump is not operating while exhaust gas is accumulating in the bag, so the subject can breathe easily. .

When cleaning the closed circuit, first
, 24 and 27, and open the solenoid valve 25 to turn on the pump 41.
, and pull it until the volume inside bellows 1 becomes 0.

When the volume reaches 0, the pump is stopped, the blower 5 is operated to introduce outside air, and the bellows 1 is filled with air.

There, the pump is operated again to exhaust the air. This operation is repeated a predetermined number of times to bring the volume of the bellows to O and complete the cleaning.

As shown in FIG. 3, the electric arm 47 that holds the mask section is rotatable, and its tip can be moved and positioned near the subject's face.

In this case, conventionally, if care was not taken in the movement of the arm, it could hit the subject and cause injury or damage to equipment. In this embodiment, the safety switch 4 is attached to the arm 47.
8, and when it comes into contact with a human body or an object, the contact is activated and the arm stops. This can prevent injury to humans and damage to equipment.

In addition, if necessary, in order to measure the amount of radioactive substances contained in the exhaled breath of the subject, a part of the exhaled breath is sampled from near the mask and detected by the scintillation detector 17. Further, the gas analyzer 18 can detect oxygen concentration and carbon dioxide concentration.

(Effects of the Invention) As explained above, according to the present invention, (1) when switching from standby mode to mixed gas inhalation mode, automatic control is performed so that the switch is automatically performed at the moment when the subject takes a breath; Fluctuations in radioactive gas concentration within a closed circuit are extremely small;
Therefore, the accuracy of inspection can be increased.

(2) The amount of gas in the bellows is constantly monitored, and when the amount falls below a predetermined amount, oxygen gas is automatically replenished to compensate for the drop in oxygen concentration, or when the amount exceeds a predetermined amount. is automatically exhausted to prevent breathing problems.
In addition, in case of an emergency, breathing can be switched to outside air, so the subject will not feel anxious at all.

(3) During bolus testing, a predetermined amount of radioactive gas is instantly transferred to the mouth of the mask using human pressure of oxygen.
The risk of the operator being exposed to radiation is eliminated, and since the thin tube C is transferred, the amount of accumulated gas inside the tube is negligible, and there is little change in the concentration of radioactive gas, allowing for efficient and highly accurate testing.

(4) In the wash-out mode, the exhaust pump is not operated constantly, but only when a predetermined amount of exhaust gas has accumulated, so the time taken for exhaust gas containing radioactive gas to pass through the trap is greatly reduced, Extends lifespan. In addition, no load is placed on the subject's breathing, and washing is performed smoothly.

(5) The electric arm is equipped with a safety switch mechanism, so even if the electrically rotating arm hits a person or property,
The arm will stop immediately, preventing injury and property damage, increasing safety.

It has remarkable effects such as

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a Douglas bag portion in an exhaust system, and FIG. 3 is a diagram showing a safety switch mechanism of an electric arm. 1...Bellows, 2...Conduit, 3.
・Soda lime, 4 ・Blower, 8 ・・
Mask conduit, 9... Mask, 10... Flow sensor, 11... Oxygen gas cylinder, 12... Xenon gas source, 13... Douglas bag, 15...
・Trap, 21-37...Solenoid valve. 41-44...Pump, 45...Switch, 48
...Safety switch. Figure 2

Claims (1)

[Scope of Claims] A bellows that expands and contracts according to the breathing of a subject, a series of conduits connected to the bellows with an inlet and an outlet, and a mixed gas of radioactive gas and oxygen gas contained in the bellows. a closed circuit equipped with a blower and carbon dioxide removal means for circulating circulation through the conduit; one end connected to a part of the conduit via a solenoid valve and having a solenoid valve for communication with outside air; A mask conduit equipped with a mask worn by the subject at the end to inhale and exhale the mixed gas, an oxygen gas source and a radioactive gas source that supply oxygen gas and radioactive gas to the closed circuit, and the test is completed. and a means for later recovering the radioactive substances contained in the mixed gas and the radioactive substances washed out from the body of the subject;
In a radioactive gas inhalation device for measuring cerebral blood flow, etc., (1) the solenoid valve connecting the closed circuit conduit and the mask conduit is closed, and the solenoid valve for communicating with outside air is opened so that the subject can breathe outside air; When switching from a standby mode in which a solenoid valve connected to the conduit is opened, a solenoid valve for communicating with outside air is closed, and the mixed gas is inhaled, the subject exhales and then inhales. (2) in the mixed gas suction mode, automatically when the mixed gas contained in the bellows becomes less than a predetermined first capacity; When a predetermined amount of oxygen gas is inhaled, and conversely, the amount exceeds a predetermined second capacity, a predetermined amount of the mixed gas is automatically exhausted, and furthermore, the state of the mixed gas in the bellows is reduced to a predetermined value. When the gas mixture continues for a predetermined period of time, and when the mixed gas remains almost full for a predetermined period of time,
A control means for controlling a switching state to an outside air breathing state by closing a solenoid valve connected to the conduit and opening a solenoid valve for communicating with outside air; (3) controlling a thin tube that connects the oxygen gas source, radioactive gas source, and mask conduit to each other During the bolus inhalation test,
a bolus inhalation mechanism that instantly transfers a predetermined amount of radioactive gas to the mouth of the mask using oxygen gas pressure; (4) a container that temporarily stores exhaust gas before the radioactive material recovery means of the mixed gas exhaust system; means for detecting the amount of exhaust gas in the container, and means for automatically exhausting the air through the radioactive material collection means when the amount of exhaust gas in the container exceeds a predetermined amount; (5) holding the mask part; and a safety switch mechanism installed on an electric arm that rotates and positions according to the position of the subject, and whose contacts close when it comes into contact with a human body or an object, stopping the rotation of the electric arm. A radioactive gas inhalation device characterized by being provided with.