CH660118A5 - APPARATUS FOR PRODUCING A FOG AND IN PARTICULAR FOR THE DIAGNOSIS OF RESPIRATORY DISEASES AND ALLERGIES. - Google Patents

Description

This invention relates to an apparatus, in particular for the diagnosis of respiratory diseases, and more particularly to an apparatus using a radioactive isotope projected inside the lungs in the form of an aerosol, which makes it possible to obtain multiple images having a resolution and a relatively high contrast, thus facilitating the localization of emboli, tumors and other similar anomalies as well as other diseases affecting the respiratory tract without the risk of excessive deposition or loss of sharpness of the images.

Until now, the diagnosis of respiratory diseases has been mainly made by explorations of the lungs using infusions and inhalations of radioactive gases. Various technical solutions have been proposed in the past. They are described in particular in the following patents: US-A-4,094,317., US-A-4,116,387., US-A-4,177,945., US-A-3,976,050. and US-A-3,992,513. The possibility of using radioactive aerosols was also examined, but it was found that too much deposition took place not only in the upper part of the respiratory tract (pharynx, trachea), but also at the intersections of the respiratory tract. On the other hand, it has been found that the mist is not deposited in the same way in the central and peripheral areas of the lungs. On the other hand, when we inhale radioactive gases such as xenon and krypton, they are expensive to produce, the patient is inconvenienced, we only have a short time even if we want to take a single image of the lung, finally you have to collect the inhaled gas and get rid of it.

This invention overcomes the problems encountered so far in diagnosing lung diseases. It proposes an apparatus using a radioactive mist which makes it possible to eliminate the problems associated with the use of gases, as well as the problems hitherto encountered with aerosols. More specifically, it has been found that in aerosols whose particles are less than about 1.2 microns in size, the vast majority of them having a size much less than 1 micron, the mist 20 behaves like a gas and does not produce condensation and excessive deposition in the upper part of the respiratory tract, i.e. the pharynx and the trachea. In addition, for the most part, the deposit formed is uniform in the whole lungs, without accumulation at the branching points of the respiratory tract, the patient can stand in any position and is not obliged to hold his breath for the exploration for which we have all the time necessary. Furthermore, the radioactive isotope being present in the form of an aerosol can, once expired, be separated by filtration and stored under good safety conditions until its radioactivity has sufficiently decreased so that one can can get rid of it. From this point of view, radioactive gases cannot be filtered, great care must be taken to store them, and this storage is long compared to that of aerosols.

The invention therefore relates to a device for fog-35 intended to be inhaled by a patient as defined in claim 1.

The main characteristics of such a device are simplicity, reliability, ease of use and relatively low cost. This device allows among other things to take multiple photogra-40 phies of the lungs practically without inconvenience the patient; more particularly, it makes it possible to obtain images of the lungs during ventilation with a resolution and a contrast that are much better than those obtained using existing devices.

The apparatus uses a vaporizer producing particles the maximum size of which is essentially limited to 1.2 microns, the proportion of particles greater than 1.2 microns being negligible. An air non-return valve is connected to the outlet of the vaporizer, and the common outlet connected by a non-return valve and a Y-shaped or T-shaped fitting to a mouthpiece or to a face mask by which the patient inhales the mist produced by the vaporizer. The third opening, or discharge opening located on the connector, includes a non-return valve; it is through this opening that the mist and air exhaled by the patient are sent to a filter retaining the radioactive mist. The outlet of the filter is preferably 55 connected to a container allowing the product to be stored until its radioactivity is low enough to allow it to be disposed of under good safety conditions. As the vaporization is generally carried out continuously by compressed air, the outlet of the vaporizer is provided with a device preventing the development of an excessive flow during exhalation.

The characteristics and advantages of the invention described above will become apparent on reading the following description, accompanied by drawings.

Fig. 1 is a side and partly schematic view of an embodiment of the apparatus according to the invention, and FIG. 2 is a side view and partly schematic of a modification of the embodiment of the invention shown in FIG. 1.

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660,118

Although it has previously been proposed to use aerosols or radioactive mists for the diagnosis of pulmonary diseases because the method would have been convenient and inexpensive, it has not been able to be used until now because the aerosols are deposited excessively in the large diameter pulmonary ducts, in the bottom of the pharynx, trachea, stomach, etc. Furthermore, it was generally considered that a radioactive mist is simply satisfactory if it does not contain particles with an average diameter greater than 2 microns. In the invention which will now be described, it has been found that not only the particles of the aerosol must not be greater than 1.2 microns, but also that they must have a size between 0.056 microns and 1.2 micron, with about 90% of the particles having less than 1 micron. Under these conditions, the aerosol behaves like a gas and the aims sought are achieved.

To prepare aerosols intended for the exploration of the lungs using radioactive substances, one can use either a colloid ■ "" 'technetium, or "mtechnetium-pentethyl acetate of diethylenetri-amine. The period of the isotope is in effect of about 6 hours, which is enough to take the necessary multiple images, while remaining short enough to allow to get rid of them properly. When using gases, not only the patient must hold his breath during exploration, which allows only one image to be taken, but still gases suitable for this use such as krypton have a period of less than 30 seconds, which even makes it difficult to take an image. The radioactive isotopes of xenon have periods ranging from 4 to 30 days, so it is difficult to get rid of. The radioactive technetium compounds given above are generally available in nuclear medicine departments for clinical diagnostic routines. born; they are therefore a convenient source for making inexpensive aerosols for exploring the lungs.

If we now refer to fig. 1 which is a schematic side representation of an embodiment of the device according to the invention, the vaporizer designated by the number 10 has a compressed gas inlet 11 and an outlet 12. Although the vaporizer can take any form desired in the embodiment shown, the body of the vaporizer comprises an appropriate reservoir, a suction system for producing the mist and a supply of gas - oxygen or air - whose flow rate is of the order of 6 to 10 liters per minute. In the embodiment of the invention shown, a 4-way connector designated by the number 13 is connected by the tubing 14 to the outlet 12 of the vaporizer 10. An air non-return valve 15 is connected to a second tube 16 of the 4-way connector 13. A non-return valve 17 and a particle filter 18 are connected to the third tube 19 of the 4-way connector 13. The fourth tube 20 of the connector 13 is connected to a flexible pipe in accordion 21 to direct the aerosol towards the patient's mouth. It is preferable that the vaporizer 10 as well as the connector 13 be enclosed inside a container 22 of lead or of another material impermeable to radiation, since the vaporizer contains a radioactive liquid.

The outlet of the pipe 21 is connected to a third non-return valve 23 which can be enclosed inside a second container 24, also made of lead or another material impermeable to radiation. The outlet of the non-return valve 23 is connected to one of the pipes 25 of a Y-shaped fitting 26 located inside the container 24. The second pipe 27 of the Y-shaped fitting is connected to a pipe. flexible 28 similar to the pipe 21. The end of the pipe 28 has a mouth 29 which allows the patient to inhale in a comfortable manner the mist formed in the vaporizer 10 and mixed with the air coming from the check valve. -return 15. Although the apparatus has been shown with a mouthpiece 29, a facial mask can be used in place of this mouthpiece 29 when desired. The non-return valve 23 can take any shape; it is preferably adjusted so as to prevent a flow when the pressure downstream of the valve is identical to atmospheric pressure, and to allow a free flow when the pressure downstream of the valve is reduced by the inspiration of the patient.

When aerosols are used to perform pulmonary explorations, the patient can breathe in and out several times to ensure that the radioactive mist is deposited uniformly through the lungs. When he exhales, the patient exhales the air through the mouthpiece (or the facial mask as the case may be) and the pipe 28. As the non-return valve 23 prevents the passage of the mist in the opposite direction, the aerated aerosol will exit through the tubing 30 of the Y-shaped connector 26 to be evacuated through the non-return valve 31 and a filter 32 to the outlet tube 33. The filter 32 retains the aerosol exhaled by the patient and keeps it until '' that the level of radioactivity is low enough to allow its elimination under good conditions of safety. During expiration, the valve 23 remains closed and it is necessary to prevent the development of excessive pressure in the tube 21 due to the supply of the atomizer 10 by the compressed air arriving through the inlet 11. C ' this is why the pipe 21 is in the form of an accordion: this allows it to expand and prevent an excessive increase in pressure. It is also possible to provide a non-return valve 17 operating as a safety valve, which makes it possible to limit the pressure in the line 21. When such a safety valve 17 is present, a filter 18 must be provided to retain the aerosol. The filtered air is then evacuated via line 34. When desired, the lines 33 and 34 can be combined and the common line directed onto a container which retains the gaseous material until its radioactivity has decreased to the point that it can be safely disposed of.

The vaporizer 10 can take any shape, provided however that the aerosol particles produced have the dimensions defined above. Such a vaporizer which effectively makes it possible to produce a mist conforming to the requirements defined above is shown and described in US Pat. No. 4,116,387.

Fig. 2 shows a modified embodiment of the invention comprising a coarse particle trap which can be included when a particular vaporizer 10 produces an excessive proportion of such particles.

In the two figures, the same figures have been used to designate the same elements.

We notice in fig. 2 that the tube 20 starting from the 4-way connector is bent upward to engage in the vertical branch of an elbow 35 having a number of inclined baffles 36. The horizontal outlet branch of the elbow 35 is connected to the accordion-shaped pipe 21 for conveying the mist to the patient. The baffle device at the elbow 35 forces the fog particles to follow a complicated circuit: large particles having a greater mass will tend to strike the baffles and will thus be eliminated from the aerosol. These larger particles will agglomerate into droplets which will automatically fall back into the vaporizer and into its liquid reservoir. A specific line can be used to return this liquid directly to the tank or to another separate container.

The apparatus using an aerosol to carry out the exploration of the lungs has been found to be perfectly effective: not only the costs are modest and the patient is little inconvenienced, but also the images obtained are enormously improved, which considerably facilitates the diagnosis of difficulties. involving all of the lungs.

Although the apparatus according to the invention is particularly useful for the exploration of the lungs, it can also be useful for sending medicaments into the lungs to treat a disease. For example, the method and apparatus could be useful for treating the lungs with antimicrobial or antifungal products, radioactive anticancer drugs, etc. The device is also useful for provoked allergy tests to determine the sensitivity of the organism for example to histamines and to antigens such as those from ragweed, etc.

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Claims (7)

660,118 1. Apparatus for producing a mist intended to be inhaled by a patient and having the properties of a gas to facilitate penetration into the entire lungs where it is deposited uniformly in all the conduits, comprising a liquid outlet using a gas under pressure to produce by suction during the normal process of respiration a mist whose particles have a size of between 0.056 micron and 1.2 micron with a majority of particles less than 1 micron, a pipe (21) provided with a device making it possible to limit the flow rate connected by one end to the above-mentioned liquid outlet, a non-return valve (15) communicating with the above-mentioned pipe to allow the entry of ambient air therein, a second valve non-return valve (23) mounted on the other end of the above-mentioned pipe, a second pipe (28) connected to the second non-return valve (23) and ending with an outlet (29) through which the mist is inhaled by the patient, and a third check valve (31) mounted on the second pipe so as to allow the flow of gas in a direction opposite to the direction of the gas in the aforementioned first and second valves, where the patient The above mentioned inhales by inhaling the mist coming from the above mentioned liquid outlet and where it exhales the mist and the gas by the third valve while exhaling. 2. Apparatus according to claim 1, comprising a device for stopping particles having a diameter greater than 1.2 microns located between the above-mentioned liquid outlet and the above-mentioned first pipe. 2 3. Apparatus according to claim 1, characterized in that the flow is between 6 and 10 liters per minute and that the device for limiting the flow consists of an accordion-shaped arrangement of the wall of the first pipe. 4. Apparatus according to claim 1, characterized in that the device for limiting the flow includes a safety valve in communication with the aforementioned liquid outlet. 5. Apparatus according to claim 1, characterized in that the above-mentioned mist is radioactive and that the third non-return valve (31) comprises a filter (32) for eliminating the radioactive mist, while allowing the evacuation of the gas as that air or oxygen, which was mixed with this fog. 6. Apparatus according to claim 5, characterized in that the device making it possible to limit the above-mentioned flow rate comprises a safety valve (17) and a filter (18) for eliminating the radioactive mist while allowing the gas such as air or oxygen, which was mixed with this mist. 7. Apparatus according to claim 1, characterized in that it comprises a device connected to the pipe (28) to facilitate the inhalation of the mist by the patient.