Abstract:
The present disclosure relates to a lung phantom system provided with an elastic film that separates a first chamber and a second chamber having inner space that may be filled with liquid, the elastic film configured to repeat expansion and restoration according to introduction and discharge of liquid, thereby providing an effect of accurately replicating movements of an actual lung during its respiratory movement.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of Korean Patent Application No. 10-2015-0114084, filed on Aug. 12, 2015, in the Korean Intellectual Property office, the entire contents of which are incorporated herein by reference in their entirety. 
       BACKGROUND 
       [0002]    Field 
         [0003]    The present disclosure relates to a phantom system. More particularly, the present disclosure relates to a lung phantom system capable of replicating an actual respiratory movement with accuracy. 
         [0004]    Description of Related Art 
         [0005]    Due to changes in life patterns and eating habits caused by modernization, incidence rates of various kinds of cancer are increasing. In addition, medical equipment has advanced and so it has become possible to photograph a human body and diagnose cancer at an early stage using various newly developed diagnostic devices, identify the location of cancer cells, and kill or prevent the cancer cells from propagating further using radiation treatment and the like, thereby treating the cancer or alleviating the pain of the patient. 
         [0006]    However, exposing an actual human body to a diagnostic device in order to check the accuracy, performance and the like of the device in the process of developing and manufacturing the new diagnostic device is very dangerous. 
         [0007]    Therefore, when developing various kinds of medical equipment or treatment methods, a phantom, which is a model of a human body, is used. 
         [0008]    There are two kinds of such phantoms: static model phantoms and dynamic model phantoms. 
         [0009]    Static models are phantom models used when taking X-rays, 3D-CT and the like. These models replicate only the shapes of a human body, and not its movement. 
         [0010]    Dynamic models are phantom models made to replicate not only the shapes of a human body such as a heart or lung, but also its movements. 
         [0011]    However, in conventional phantom systems, water is thrusted into a sponge phantom having the shape of a human body and then the phantom is contracted to replicate movements of the human body, and thus pressure is applied evenly to all surfaces of the phantom, making all the surfaces of the phantom contract or expand identically. 
         [0012]    Otherwise, one surface of the phantom is thrusted perpendicularly so that it contracts linearly. 
         [0013]    However, such movements are quite different from the movements of an actual lung, and thus there is a need to develop a lung phantom system that can replicate the actual respiratory movements with accuracy. 
       SUMMARY 
       [0014]    A purpose of the present disclosure is to solve the aforementioned problems of prior art, that is, to provide to a lung phantom system capable of replicating respiratory movements of an actual lung with accuracy. 
         [0015]    Another purpose of the present disclosure is to provide a lung phantom system capable of replicating movements of an actual lung with accuracy by using an elastic film. 
         [0016]    Another purpose of the present disclosure is to provide a lung phantom system capable of accurately replicating movements of air being inhaled and exhaled during an actual respiration by using sine waveform driving signals. 
         [0017]    Another purpose of the present disclosure is to provide a lung phantom system capable of replicating movements of an actual lung with accuracy by using a phantom formed by two or more kinds of blocks having different elastic moduli. 
         [0018]    Another purpose of the present disclosure is to provide a lung phantom system capable of representing target cells such as cancer cells by forming a phantom including a target block displayed differently from the remaining blocks in a photographed image of a diagnostic device. 
         [0019]    According to an embodiment of the present disclosure, there is provided a lung phantom system including a first chamber and a second chamber having inner space that may be filled with liquid, the first chamber and the second chamber separated by an elastic film; and a liquid supply unit that supplies the liquid into the second chamber through a liquid inlet formed in the second chamber or removes the liquid from the second chamber through the liquid inlet, wherein the elastic film expands towards inside the first chamber as the liquid is supplied by the liquid supply unit into the second chamber, and the elastic film is restored back to its original position as the liquid is discharged from the second chamber by the liquid supply unit. 
         [0020]    The liquid supply unit may include a liquid supply tube connected with the liquid inlet; a liquid supplier that supplies the liquid to the liquid supply tube or sucks the liquid from the liquid supply tube; and a driver that actuates the liquid supplier. 
         [0021]    A driving signal of the driver may be a signal having a sine waveform replicating respiration. 
         [0022]    The lung phantom system may further include a phantom that is disposed inside the first chamber, and that contracts as the elastic film expands and is restored back to its original state as the elastic film is restored. 
         [0023]    The lung phantom system may further include an air tube formed to penetrate one surface of the first chamber so as to connect the inner space and outer space of the first chamber; and an inner film that surrounds the phantom such that the liquid does not directly contact the phantom but such that the phantom and outside air are communicable with each other through the air tube. 
         [0024]    The phantom may consist of at least two groups of blocks having different elastic moduli from each other. 
         [0025]    The phantom may consist of a plurality of layers, and a plurality of the blocks forming at least one layer of the plurality of layers may consist of the at least two groups of blocks having different elastic moduli from each other. 
         [0026]    A portion of the blocks may be a target block that is displayed differently from the other blocks when photographing the phantom with a diagnostic device. 
         [0027]    The present disclosure can provide a lung phantom system capable of accurately replicating movements of an actual lung in respiratory movements. Further, such a phantom can represent movements identical to the actual movements and locations of a tumor, thereby providing an effect as an alternative to patients when assessing 4D-CT performance and measuring the amount of radiation, etc. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the example embodiments to those skilled in the art. 
           [0029]    In the drawing figures, dimensions may be exaggerated for clarity of illustration. It will be understood that when an element is referred to as being “between” two elements, it can be the only element between the two elements, or one or more intervening elements may also be present between two elements. Like reference numerals refer to like elements throughout. 
           [0030]      FIG. 1  is a schematic view of a lung phantom system according to an embodiment of the present disclosure; 
           [0031]      FIG. 2  is a view illustrating movements of a lung phantom system provided to illustrate the shape of a lung during an exhale; 
           [0032]      FIG. 3  is a view illustrating movements of a lung phantom system provided to illustrate the shape of a lung during an inhale; 
           [0033]      FIG. 4  is a schematic view of a lung phantom system according to another embodiment of the present disclosure; 
           [0034]      FIGS. 5 and 6  are perspective views exemplifying a phantom structure that may be used in a lung phantom system according to the present disclosure; 
           [0035]      FIG. 7  is a view exemplifying a screen of a phantom including a target block, photographed by a diagnostic device; 
           [0036]      FIG. 8A  is a photograph showing the shape of a lung phantom system during an inhale according to an embodiment of the present disclosure; 
           [0037]      FIG. 8B  is a photograph showing the shape of a lung phantom system during an exhale according to an embodiment of the present disclosure; 
           [0038]      FIG. 9A  is a photograph showing the shape of an actual lung during an inhale; and 
           [0039]      FIG. 9B  is a photograph showing the shape of an actual lung during an exhale. 
       
    
    
     DETAILED DESCRIPTION 
       [0040]    Hereinafter, a lung phantom system according to the present disclosure will be explained in detail with reference to the drawings attached. 
         [0041]    In the explanation hereinafter, only the portions necessary for understanding a lung phantom system according to embodiments of the present disclosure will be explained, and explanation on other portions may be omitted so as not to obscure the main point of the present disclosure. 
         [0042]    Further, the terms and words used in the present specification and claims to be explained hereinafter should not be construed as limited to their general or dictionary meanings, but should be construed as meanings and concepts suitable to the technical concept of the present disclosure that express the present disclosure most suitably. 
         [0043]      FIG. 1  is a schematic view illustrating a lung phantom system according to an embodiment of the present disclosure. 
         [0044]    The lung phantom system according to the present disclosure includes a first chamber  10 , a second chamber  20 , an elastic film  30  and a liquid supply unit  40 , as illustrated in  FIG. 1 . 
         [0045]    More specifically, the first chamber  10  and the second chamber  20  are chambers having inner space that may be filled with liquid. 
         [0046]    The liquid filling the first chamber and the second chamber may be liquid such as water. 
         [0047]    The elastic film  30  is disposed between the first chamber and the second chamber, and the liquid inside the first chamber and the liquid inside the second chamber are separated by the elastic film  30  and thus do not mix. 
         [0048]    As illustrated in  FIG. 1 , a phantom  100  is disposed inside the first chamber. 
         [0049]    Inside the second chamber  20 , a liquid inlet  21  is provided. By the liquid supply unit  40  connected to the liquid inlet  21 , liquid may be supplied to or removed from the inside of the second chamber. 
         [0050]    In the case where liquid is supplied by the liquid supply unit  40  even after the second chamber  20  is filled with liquid, as illustrated in  FIG. 2 , the elastic film  30  expands towards the inside of the first chamber  10  due to pressure, whereby the inner space of the first chamber decreases, and by this pressure, the phantom  100  contracts. 
         [0051]    Further, in the case where liquid is removed by the liquid supply unit  40 , as illustrated in  FIG. 3 , the elastic film  30  is returned back to its original position, whereby the inner space of the first chamber increases again, and the phantom  100  expands again and is returned back to its original shape. 
         [0052]    It is desirable that the elastic film  30  is made of a material having elastic force in a shape that can form a flat diaphragm between the first chamber  10  and the second chamber  20  when pressure is not applied so that it operates to replicate the respiratory movements mentioned above. 
         [0053]    Further, it is desirable that the elastic film  20  has as much elastic force and rigidity as not to be deformed or damaged even after repeating the operations of replicating the respiratory movements. 
         [0054]    As illustrated in  FIG. 1 , the liquid supply unit  40  that supplies liquid to the inside of the second chamber  20  may include a liquid supply tube  41  connected to the liquid inlet  21  of the second chamber, a liquid supplier  42  that supplies or discharges liquid to the liquid supply tube  41 , and a driver  43  that actuates the liquid supplier  42 . 
         [0055]    More specifically, the liquid supply tube  41  is connected between the second chamber  20  and the liquid supplier  42  to provide a space where the liquid can move. The liquid supplier  42  can be directly connected to the second chamber. However, by spacing the liquid supplier  42  that includes a metal material apart from the second chamber using a liquid supply tube made of a non-metal material, it is possible to prevent the metal artifact phenomenon that may occur during a computerized tomography (CT). 
         [0056]    Further, the liquid supply tube  41  also has an effect of preventing damage to the chamber unlike in a conventional phantom system where the liquid supplier  42  is directly connected to a chamber. 
         [0057]    The liquid supplier  42  is a device configured to supply or discharge liquid. As illustrated in  FIG. 1 , the liquid supplier  42  may be a piston device, a pump or the like, but there is no limitation thereto, and thus any device configured to supply and discharge liquid may be used as the liquid supplier  42 . 
         [0058]    The liquid supplier is actuated by the driver  43  such as an actuator, wherein it is desirable that a signal of the driver  43  is a signal having a sine waveform so as to similarly replicate respiration of an actual lung. 
         [0059]    Further, in the case where the lung phantom system replicates lung movements of a certain patient, it is desirable that the respiration volume during an exhale and an inhale of the patient are measured, and that a driving signal of the liquid driver is a signal having the sine waveform corresponding to the measured respiration volume. 
         [0060]      FIG. 4  illustrates a lung phantom system according to another embodiment of the present disclosure. Unlike the lung phantom system of  FIG. 1 , the lung phantom system according to the another embodiment of the present disclosure illustrated in  FIG. 4  has an air tube  11  formed inside the first chamber  10 , and further includes an inner film  50  that surrounds the phantom  100  disposed inside the first chamber. 
         [0061]    More specifically, the air tube  11  is formed to penetrate one surface of the first chamber so as to connect the inner space and the outer space of the first chamber. 
         [0062]    The inner film  50  is a thin film like a plastic bag that surrounds the phantom to prevent the liquid inside the first chamber from directly contacting the phantom  100  as illustrated in  FIG. 4 , so that the phantom  100  is communicable with outside air through the air tube. 
         [0063]    In such a lung phantom system according to the another embodiment of the present disclosure, when liquid flows inside the second chamber  20  and thus the elastic film  30  expands towards the inside of the first chamber  10 , the pressure being applied to the phantom increases, whereby the air that used to be inside the phantom is discharged towards outside through the air tube  11  and the volume of phantom  100  contracts. 
         [0064]    Then, when the liquid is discharged from the inside of the second chamber  20  and thus the elastic film  30  returns back to its original position, the pressure being applied to the phantom decreases, whereby outside air naturally flows into the inner film  50  through the air tube  11  and the volume of the phantom also increases to its original shape. 
         [0065]    Such a lung phantom system according to the another embodiment of the present disclosure may provide movements of the phantom that are similar to the respiratory movements of an actual lung, as the air inside the phantom is naturally discharged towards outside and then introduced back in. 
         [0066]    In such a lung phantom system according to the embodiments of the present disclosure explained hereinabove, the phantom  100  may be made of a material having elasticity and compressibility such as sponge, latex and the like so that it may be restored back to its original state when pressure is removed. 
         [0067]    Especially, by attaching a plurality of unit blocks  1  to form a lung phantom as illustrated in  FIG. 5 , it is possible to easily form a lung phantom replicating different shapes and sizes for different patients. 
         [0068]    Especially, since a lung does not contract or expand identically in every position during an exhale and an inhale, it is desirable to form a phantom using at least two kinds of blocks  101 ,  102  having different moduli from each other as illustrated in  FIG. 6  so that the lung movements can be replicated with accuracy. 
         [0069]    More specifically, a phantom may be formed using at least two groups of blocks  101 ,  102  as illustrated in  FIG. 6 . If the elastic modulus of a B group block  102  is higher than that of an A group block  101 , the B group block  102  is harder than the A group block, and thus the B group block  102  contracts less than the A group block under a same pressure, and when the pressure is increased or decreased, the sponge block in the A group  101  contracts or expands further than the blocks in the B group. 
         [0070]    By using blocks having different elastic moduli as aforementioned, it is possible to easily form a phantom replicating a human organ of which the composition differs from person to person. 
         [0071]    Further, by arranging a greater number of blocks with low elastic modulus in the lower portion of the phantom  100  than in the upper portion thereof as illustrated in  FIG. 6 , it is possible to replicate lower areas of the lung where the volume change rate is higher than upper areas according to respiratory movements with increased accuracy. 
         [0072]    Further, in the case of photographing some of the blocks forming a lung phantom with a diagnostic device such as an ultrasound device, CT and the like as illustrated in  FIG. 7 , by forming a target block  103  to be displayed differently from the rest of the blocks in a photographed image, it becomes possible to see how a target cell such as a cancer cell in the lung moves during respiratory movements. 
         [0073]    For this purpose, it is desirable that the target block  103  is made of a material having a density different from the rest of the blocks. Here, it is desirable that the density is similar to that of human skin, muscles, and organs; lower than that of human bone; higher than that of water; and lower than that of the chamber. 
         [0074]    Further, since the target block  103  should be able to change its shape together with the other blocks according to respiratory movements, it is desirable that the target block  103  is made of a material having elastic force. 
         [0075]    Therefore, the target block  103  may be made of silicon rubber or a material similar to silicon rubber having high elasticity and tensile force, and suitable density. 
         [0076]    CT photographs taken while operating a lung phantom system according to the embodiment of the present disclosure explained hereinabove are illustrated in  FIG. 8A  and  FIG. 8B , and one can see that the shapes of the phantom of  FIG. 8A  and  FIG. 8B  are very similar to the photographs of an actual lung illustrated in  FIGS. 9A and 9B . 
         [0077]    Further, since it is possible to see movements of the target block  103  as well, it is possible to accurately replicate movements of a tissue such as a lung that has high volume change rates and possibilities that the location, shape and the like of a tumor may change depending on movements, proving that the lung phantom system according to the embodiments of the present disclosure may be used as an alternative to patients when assessing 4D-CT performance and measuring the amount of radiation, etc. 
         [0078]    So far, a phantom and a lung phantom system according to the present disclosure were explained with reference to specification embodiments of the present disclosure. 
         [0079]    In the drawings and specification, there have been disclosed typical embodiments of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.