NZ203664A - Apparatus for diagnosing lung disease using radioactively tagged mists - Google Patents

Description

203664 Prioiily Date(s): 13^.- 3.-33 Complete Specification Filed: S.'3;-3.tS3 CJass: Publication Date- P.O. Journal, No- . s liq BRAWINQS new zealand patents act, 1953 No.' Dale: complete specification APPARATUS FOR THE DIAGNOSIS OF RESPIRATORY DISEASES AMD ALLERGIES l/MS, CARL PETER KREMER, JR., a United States citizen of 8 Rings End Road, Darien, Connecticut 06820, United States of America hereby declare the invention for which I / flRe^pray that a patent may be granted to me/w, and the method by which it is to be performed, to be particularly described in and by the following statement:- 203664 This invention relates to Che diagnosis of respiratory disease and more specifically to a novel and improved apparatus utilizing an aerosolized radioactive isotope for ven-tillation of the lungs to enable the production of multiple images of relatively high resolution and contrast to facilitate location of emboli, tumors and the like as well as other diseases affecting the respiratory tract without the danger of hyperdepo-sition and loss of image clarity.

Heretofore, diagnosis of respiratory diseases was principally effected by perfusion lung scans and ventillation utilizing radioactive gases. The use of radioactive aerosols was also considered but it was found that with known systems excessive deposition or rainout occurred not only in the upper respiratory tract, the oral pharynx or the trachea but also at airway intersections. Moreover, uneven deposition of the mist was observed between the central and peripheral areas of the lung. Accordingly, when ventillation scans are deemed desirable, radioactive gases such as xenon and krypton are generally relied upon notwithstanding the relatively high cost entailed in producing the gas, patient inconvenience, extremely limited time in which to obtain even one image of the lung and the need for containment and disposition of the exhaled gas.

It is an object of the invention to go some way towards overcoming the above problems or at least to provide the public with a useful choice.

The invention provides apparatus utilizing a radioactive mist which avoids the difficulties entailed with gases as well as the problems heretofore encountered with aerosols.

More specifically, it has been found that ^ ^ A; 203664 with Che utilization of aerosols wherein the particle size is maintained below approximately 1.2 microns with by far the major portion of the particles being well below 1 micron, the mist behaves much the same as a gas and does not produce material rain-out or hyperdeposition in the upper respiratory tract, pharynx or trachea. Moreover, there is substantially uniform deposition throughout the entire lung without accumulation at airway branching points and the patient can be in any position and is not required to hold his breath during the scanning operation and ample time is available for multiple scans. Furthermore, the isotope being in aerosol form can, upon being exhaled, be filtered out and safely stored until the radioactivity reaches a Bafe level for convenient disposition. Radioactive gases however cannot be filtered and great care is required for containment and storage, the latter requiring extended periods of tjjme aa compared to aerosols.

The invention utilizes a nebulizer wherein the maximum particle size is essentially limited to 1.2 microns with a negligible quantity of particles larger than 1.2 microns. A unidirectional air inlet is coupled to the output of the nebulizer and the output is also coupled through a unidirectional flow valve and a T- or Y- connector to a mouthpiece or face mask through which the patient inhales the mist produced by the nebulizer. The third or discharge opening on the connector includes a unidirectional flow valve for the discharge of mist and air exhaled by the patient and a filter for the removal of the radio active mist. The output from the filter is preferably fed to a suitable container for storage until the radioactivity decays to a safe level for disposal. Since the nebulizer is usually operated continuously by a compressed air supply, means are also pro vided at the output of the nebulizer to prevent the development of excess pressure during the exhaling periods. 2 203c64 Accordingly, in one aspect the invention may broadly bo said to consist in an apparatus for producing a mist to be inhaled by a patient and having gaseous properties to facilitate pervasion of the entire lung with substantially uniform deposition throughout all the airways therein comprising means including an outlet for continuously aspirating a liquid utilizing gas pressure to produce a mist to be inhaled by a patient continuously during each inspiratory phase, said mist having particles within the range of .056 microns to 1.2 microns with the major portion of the particles being less than one micron, a conduit including pressure limiting means connected at one end to said outlet, a unidirectional flow valve communicating with said conduit for the admission of ambient air, a second unidirectional flow valve connected to the other end of said conduit, a second conduit connected to said second flow valve and terminating in an outlet to facilitate inhaling of the mist by the patient, and a third unidirectional flow valve connected to said second conduit and arranged to permit flow in a direction opposite to said first and second valves whereby said patient upon inhaling will draw mist from said aspirating means and upon exhaling, the exhaled mist and gas will be discharged through said third flow valve.

In a further aspect, the invention may be said to consist in an apparatus for producing a mist to be inhaled by a patient and having gaseous properties to facilitate pervasion of the entire lung with substantially uniform deposition throughout all the airways therein comprising means including an outlet for continuously aspirating a liquid utilizing gas pressure to produce a mist to be inhaled continuously during each inspiratory phase, said mist having particles within the range of .056 microns to 1.2 microns with the major portion .. *'t . of the particles being less than 1 micron, a conduit connected O : 7 V " at one end to said outlet, a unidirectional flow valve commum- -3664 eating with said conduit for the admission of ambient air, means coupled to the other end of said conduit to facilitate inhaling of the mist by the patient, and a second unidirectional flow valve connected to said conduit and arranged to permit flow in a direction opposite to said first flow valve whereby said patient upon inhaling will draw mist from said aspirating means and upon exhaling, the exhaled mist and gas will be discharged through said second flow valve.

The above and other advantages of the invention will become more apparent from the following description and accompanying drawings forming part of this application.

IN THE DRAWINGS: Figure 1 is a side elevational view in partially diagrammatic form of one embodiment of apparatus in accordance with the invention; and Figure 2 is a side elevational view in partially diagrammatic form of a modification of the invention shown in Figure 1.

V 2036 6 While Che desirability of: uCilizing radioactive aerosols cr mists for the diagnosis of lung diseases had been suggested idealise of convenience and relatively low cost, the procedure lias not heretofore been utilized because of excessive deposition of Che aerosols in large airways, posterior pharynx, trachea, stomach and Che like. Ic was also generally considered that a satisfactory radioactive mist must merely not include particles larger than 2 microns in mean mass aerodynamic diameter. With the invention now to be described, it has been found that particle s ies not only should not exceed 1.2 microns but that the particles of the aerosol should be in the range of about .056 microns to about 1.2 microns with approximately 90% of the particles being under 1 micron. Under these conditions, the aerosol behaves as a gas and the desired objectives can be achieved.

In preparation of the aerosol for the production of radio- 9 9 m 99m active scans, either technetium-sulphur colloid or tech netium- d ie thyle ne triamine penta-acetate functioned satisfactorily and have half lives of about 6 hours which provides adequate time for multiple image scans and yet a short enough half life to provide for convenient disposal. Gases not only require the patient to hold his breath during an image scan which affords time for only a single scan but known satisfactory gases such as krypton has a half life of less than 30 seconds making it difficult to provide time for even the single scan and forms of tagged Xenon have half lives of from 4 to 30 days making disposal difficult. The radioactive technetium compounds referred to above are generally available in Nuclear Medicine Departments for rou- 203664 tine c1inica1.diagnosCic procedures and accordingly constitute a relatively inexpensive and available aerosol for the conduct of ventillation scans.

Referring now to Figure 1 showing a partially diagrammatic elevational view of one form of apparatus in accordance with the invention, the nebulizer is generally denoted by the numeral 10 and includes a compressed gas inlet 11 and an outlet 12. The nebulizer may take any desired form though in the illustrated embodiment, the housing would include a suitable reservoir, an aspirator for producing the mist and the gas such as oxygen or air should be supplied at the rate of the order of 6 to 10 liters per minute. In the instant embodiment of the invention, a four-way connector generally denoted by the numeral 13 is coupled to the outlet 12 of the nebulizer 10 by the tubular leg 14. A unidirectional air inlet valve 15 is connected to a second tubular leg 16 of the four-way connector 13, a second unidirectional outlet valve 17 and particle filter 18 are connected to a third leg 19 of the four-way connector 13 and a fourth leg 20 of the connector 13 is connected to flexible tubing 21 having a bellows configuration for delivery of the aerosol to the patient. It is preferable to enclose the nebulizer 10 together with the four-way connector 13 within a container 22 formed of lead or other radiation shielding material since the nebulizer will contain a radioactive liquid.

The outlet end of the tubing 21 is connected to a third unidirectional valve 23 which may be contained within a second container 24 also formed of lead or other radiation shielding mate rial. The outlet ot the one-way valve 23 is coupled to one leg 2 3 oi: a Y-connector 26 disposed within the container 24 and the second leg 27 of the Y-connector is coupled to a flexible tube 2S' similar to that of the tube 21. A mouthpiece 29 for the pa-tient: ls secured to the end of the tube 28 so that the patient e.in con von i out 1 y inhale the in i s c generated by the nebulizer 10 t v-L>t:her with air entering the one-way valve 15. While a simple mouthpiece 29 has been illustrated, a suitable facemask may re-n 1 aco Che mouthpiece if so desired. The unidirectional flow valve 23 may take any desired form and may preferably be adjusted Co prevent flow during the presence of atmospheric pressure on the downstream side of the valve and provide for free flow when the downstream pressure is reduced during the time the pa-cient is in the process of inhaling.

When utilizing aerosols for ventillation scans, the patient may inhale and exhale several times in order to be certain that the radioactive mist has been uniformly deposited throughout the entire lung. During the exhaling periods, the patient will exhale Chrough the mouthpiece or facemask, as the case may be, and through the tube 28. Since the one-way valve 23 will prevent reverse clow of mist, the exhaled aerosol will pass outwardly through the leg 30 of the Y-connector 26, a one-way valve 31 and a filter 32 and the exhaled air and/or gas will be discharged through the Cube 33. The filCer 32 retains the aerosol exhaled by the patient and contains the filtered aerosol until the level of radioactivity has decreased to a safe level for convenient disposal. During the exhaling period, the valve 23 will remain closed and it is therefore desirable to prevent development of 2 036 64 excessive pressure within the tube 21 caused by compressed air entering the inlet 11 of the nebulizer 10. For this purpose, the tubing 21, being in the form of: a bellows, will tend to expand and thus limit the pressure. If desired, the one-way valve 17 may be utilized and adjusted to act as a relief valve to limit the maximum pressure in the tube 21. When the relief valve 17 is utilized, an aerosol filter 18 is provided to filter out and contain the aerosol and the remaining gas is discharged through the pipe 34. If desired, pipes 33 and 34 may be coupled together and fed to a holding container which will retain the gaseous material until the radioactivity has decreased to a level permitting normal disposal.

The nebulizer 10 may take any desired form provided however that the aerosol particles generated thereby are within the ranges set forth above. One such nebulizer which will generate a mist meeting the requirements outlined above is illustrated and described in United States Patent No. 4,116,387.

Figure 2 illustrates a modified embodiment of the invention wherein a large particle trap is included in the event the specific nebulizer 10 utilized may have an excess number of large par-t icles .

In the figures, like numerals have been used to denote corresponding elements in each figure.

In Figure 2, it will be observed that the leg 20 extending from the four-way connector 13 is curved upwardly and receives the vertical leg of an elbow 35 having a plurality of inclined baffles 36. The horizontal output leg of the elbow 35 is then 203664 coup led to the bellows-shaped tubing 21 for delivery of the mist o .1 patient.

Tin.- baffle arrangement contained within the elbow 35 provides a circuitous path tor the mist with the result that the larger particles which because of their greater mass will tend to collide with one of the baffles and be removed from the remainder of the aerosol. These larger particles upon reconversion to a liquid will automatically drain back into the nebulizer and enter the liquid reservoir therein. If desired, a separate drain may be employed for returning this liquid directly to the reservoir or to an individual receiver.

The method and apparatus for the production of lung scans utilizing an aerosol has been found to be exceedingly effective not only from the standpoint of reduced costs and convenience for the patient but vastly improved image scans have been obtainable which greatly facilitate diagnosis of precise difficulties involving the entire lung.

While the invention is particularly useful for the production of image scans of the lung, it is of course useful for medication of the lung in the treatment of disease. For instance, the method and apparatus would be useful for treatment of the lung with antimicrobials, antifungals, tagged anticancer drugs and the like. The method and apparatus is also useful for provocative allergy testing to determine the body reaction, for instance, to histamines and antigens such as ragweed and the like.

While only certain embodiments of the invention have been illustrated and described, it is apparent that alterations, 2 036 64 ciunees and modifications may be made without departing from the tr'je scope and spirit thereof.

Claims (1)

1. 203664 WHAT I CLAIM IS: 1. Apparatus for producing a mist to be inhaled by a patient and having gaseous properties to facilitate pervasion of the entire lung with substantially uniform deposition throughout all the airways therein comprising means including an outlet for continuously aspirating a liquid utilizing gas pressure to produce a mist to be inhaled by a patient continuously during each inspiratory phase, said mist having particles within the'range of .056 microns to 1.2 microns with the major portion of the particles being less than one micron, a conduit including pressure limiting means connected at one end to said outlet, a unidirectional flow valve communicating with said conduit for the admission of ambient air, a second unidirectional flow valve connected to the other end of said conduit, a second conduit connected to said second flow valve and terminating in an outlet to facilitate inhaling of the mist by the patient, and a third unidirectional flow valve connected to said second conduit and arranged to permit flow in a direction opposite to said first and second valves whereby said patient upon inhaling will draw mist from said aspirating means and upon exhaling, the exhaled mist and gas will be discharged through said third flow valve. Apparatus according to claim 1 including large particle intercepting means interposed between the output of said aspirating means and said first conduit. 3; Apparatus according to claim 1 wherein said gas pressure is in the range of 6 to 10 Liters per minute and said pressure limiting means comprises an undulating bellow-like wall on said first conduit. 11 2.0 36 ©4 4- Apparatus according to claim 1 wherein said pressure limiting means comprises a pressure relief valve communicating with the outlet of said aspirating means. 5- Apparatus according to claim 1 wherein said mist is radioactive and said third flow valve includes a filter for removal of the radioactive mist while permitting discharge of the gas such as air or oxygen combined -with the mist. _6- Apparatus according to claim 5 wherein said pressure limiting means comprises a pressure relief valve and a filter for the removal of the radioactive mist while permitting discharge of the gas such as air or oxygen combined with the mist. 7. Apparatus for producing a mist to be inhaled by a patient and having gaseous properties to facilitate pervasion of the entire lung with substantially uniform deposition throughout all the airways therein comprising means including an outlet for continuously aspirating a liquid utilizing gas pressure to produce a mist to be inhaled continuously during each inspiratory phase, said mist having particles within the range of .056 microns to 1.2 microns with the major portion of the particles being less than 1 micron, a conduit connected at one end to said outlet, a unidirectional flow valve communicating with said conduit for the admission of ambient air, means coupled to the other end of said conduit to facilitate inhaling of the mist by the patient, and a second unidirectional flow valve connected to said conduit and arranged to permit flow in a direction opposite to said first flow valve whereby said patient upon inhaling will draw mist from said aspirating means and upon exhaling, the exhaled mist and gas will be discharged through said second flow valve. 3-03664 8. Apparatus for producing a mist to be inhaled by a patient substantially as herein described with reference to the accompanying drawings. ^r.i.. 7$C Ey l-Hs/JtetTftuthorisod Ayonis, A. J. PAR:-C & SON