Patent Publication Number: US-2021177260-A1

Title: Urinary catheter for detecting radiation

Description:
BACKGROUND 
     Limitations and disadvantages of conventional approaches to data storage will become apparent to one of skill in the art, through comparison of such approaches with some aspects of the present method and system set forth in the remainder of this disclosure with reference to the drawings. 
     BRIEF SUMMARY 
     A urinary catheter is provided for detection and tracking of a radiation dose in radiotherapy substantially as illustrated by and/or described in connection with at least one of the figures, as set forth more completely in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example interstitial brachytherapy treatment using an afterloader directed at a tumor in a patient&#39;s prostrate in accordance with aspects of this disclosure. 
         FIG. 2  illustrates the placement of an exemplary urinary catheter in accordance with aspects of this disclosure. 
         FIG. 3A  illustrates an exemplary urinary catheter for measuring radiation in accordance with aspects of this disclosure. 
         FIG. 3B  illustrates a cutaway view of an exemplary urinary catheter for measuring radiation in accordance with aspects of this disclosure. 
         FIG. 4A  illustrates the placement of an exemplary urinary catheter in accordance with aspects of this disclosure. 
         FIG. 4B  illustrates another placement of an exemplary urinary catheter in accordance with aspects of this disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Brachytherapy is commonly used as an effective treatment for cervical, prostate, breast, esophageal and skin cancer, and can also be used to treat tumors in many other body sites. Interstitial brachytherapy is a cancer treatment in which radioactive material is placed directly in the target tissue of the affected site, such as the prostate or breast. 
     The dose rate of brachytherapy refers to the level or intensity with which the radiation is delivered to the surrounding medium and can be expressed in Grays per hour (Gy/h). In high-dose rate (HDR) brachytherapy, the rate of dose delivery typically exceeds 12 Gy/h. During HDR brachytherapy, a radiation source is placed for a set duration (usually a number of minutes or hours) before being withdrawn. The specific treatment duration depends on many different factors, including the required rate of dose delivery and the type, size and location of the cancer. 
     A range of imaging technologies (e.g., x-ray radiography, ultrasound, computed axial tomography (CT or CAT) scans and magnetic resonance imaging (MRI)) can be used to visualize the shape and size of the tumor and its relation to surrounding tissues and organs. The data from many of these sources can be used to create a 3D map of the tumor and the surrounding tissues. Using this information, a plan of the optimal distribution of the radiation sources can be developed. This includes consideration of how the radiation should be placed and positioned. Errors or poor treatment setup might present a safety risk to the patient. Too little irradiation or too much irradiation must be avoided during treatment, as these can result in treatment failure and severe side-effects. 
       FIG. 1  illustrates an example interstitial brachytherapy treatment of a tumor  101  in a patient&#39;s prostate gland  103  in accordance with aspects of this disclosure. The size and location of the tumor  101  relative to the patient&#39;s urethra  105 , bladder  107  and rectum  109  as shown is for illustration purposes. The tumor  101  may be any size and located anywhere in the prostate  103 . 
     As shown in  FIG. 1 , an afterloader  111  is a radiotherapy machine being used to control the HDR brachytherapy treatment of the tumor  101 . A transfer tube  115  connects from the afterloader  111  to a plastic or metallic catheter  117 . The transfer tube  115  is designed to take the steel cable  113  with the radioactive source  119  from the afterloader  111  to the catheter  117 . The catheter  117  receives the radiation source  119 , and the afterloader  111  controls the movement, positioning and dwell time of the radiation source  119  within the tumor  101  as specified by a doctor&#39;s treatment plan. 
     Interstitial brachytherapy requires the precise placement of short-range radiation sources  119  (e.g., radioisotopes Cobalt-60, Iodine-125, Cesium-131, Iridium-192, etc.) closely to the site of a cancerous tumor  101 . Radiation treatment is intended to kill cancerous tissue while reducing exposure to healthy tissues. The radiation source  119  may travel throughout the catheter  117  length, while stopping at predetermined periods in specific positions, thus providing irradiation of the surrounding tissues of the tumor  101  in an isotropic way. However, if the afterloader is not properly calibrated, healthy (e.g., non-cancerous) tissues may be irradiated in error. 
     Aspects of the present disclosure provide a urinary catheter that is operable to detect and locate a radiation source.  FIG. 2  illustrates the placement of an exemplary urinary catheter in accordance with aspects of this disclosure. The urinary catheter tube  201  is located in the urethra. One end of the tube  201  comprises a urine collection hole  203  that is inserted into the bladder  107 . This end of the tube is held in place with an inflatable balloon  205  at the neck of the bladder  107 . The other end of the tube  201  is connected to an external drainage bag. 
       FIG. 3A  illustrates an exemplary urinary catheter  300  for measuring radiation in accordance with aspects of this disclosure. A plurality of radiation sensors are embedded in the walls of the urinary catheter tube  201 . Each radiation sensor comprises a fiducial marker  307 ,  317 ,  327 , a scintillator  309 ,  319 ,  329 , and an optical fiber  311 ,  321 ,  331 . Each fiducial marker  307 ,  317 ,  327  may comprise a gold tip that allows each radiation sensor to be located with an MRI scanner. Each fiducial marker  307 ,  317 ,  327  may be cylindrical and 1 mm or less. The plurality of MRI markers may be located via an MRI machine after the urinary catheter is placed in a patient and prior to radiation therapy. 
     Each scintillator  309 ,  319 ,  329  collects radiation and converts this radiation into a luminous signal with an intensity that is proportional to the level of incident radiation. The scintillator may be and inorganic or organic with cylindrical shape or organic scintillating optical fiber, matching the sectional shape and dimension of the optical fiber  311 ,  321 ,  331 . For example, each scintillators  309 ,  319 ,  329  may comprise a scintillating, multi-clad optical fiber with 0.5 mm diameter (e.g., Saint-Gobain BCF-12). The fiducial marker  307 ,  317 ,  327  may have the same diameter as the optical fiber. Each optical fiber  311 ,  321 ,  331  allows the light of the corresponding luminous signal to be carried to a light detection unit (e.g., photodetector, photodiode) of a plurality of light detection units  313 ,  323 ,  335  that can be located external to the patient. Each light detection unit  313 ,  323 ,  333  is configured to produce an electrical signal in a presence of the light from one scintillator of the plurality of scintillators  309 ,  319 ,  329 . The level of the electrical signal produced by each light detection unit  313 ,  323 ,  333  is proportional to the light incident to each light detection unit  313 ,  323 ,  333 . Thus the level of the electrical signal produced by each light detection unit  313 ,  323 ,  333  is proportional to the level of the radiation incident to each scintillator  309 ,  319 ,  329 . Each light detection unit of the plurality of light detection units  313 ,  323 ,  333  may be located near coupled to one scintillator of the plurality of scintillators  309 ,  319 ,  329  via an optical fiber. 
     A processor  337  is configured to calculate a location of the radiation source according to the electrical signals from the plurality of light detection units  313 ,  323 ,  333 . The processor  337  may be configured to calculate the location of the radiation source by triangulation according to the electrical signals from the plurality of light detection units  313 ,  323 ,  333 . The processor may also be configured to calculate a velocity of the radiation source  119  according to the electrical signals from the plurality of light detection units. 
       FIG. 3B  illustrates a cutaway view of an exemplary urinary catheter for measuring radiation in accordance with aspects of this disclosure. In this cutaway view, optical fiber  311 ,  321 ,  331  are shown to be equally spaced around the urinary catheter tube  201 . 
       FIG. 4A  illustrates the placement of an exemplary urinary catheter in accordance with aspects of this disclosure. In  FIG. 4A , the tumor  101  is irradiated by a radiation source  119  that is placed within the tumor  101  by an afterloader catheter  117 . The urinary catheter may comprise a second balloon  401  that can expand the urinary catheter tube to be closer to the tumor  101 . The scintillators  309 ,  319 ,  329  may be located around this balloon  401  and also be relocated. For example, the plurality of scintillators  309 ,  319 ,  329  and the plurality of optical fibers  311 ,  321 ,  331  may be spread out when the balloon  401  is expanded. The exact position of the scintillators  309 ,  319 ,  329  may be determined via a CT scan or MRI before the radiation begins by mapping the fiducial markers  307 ,  317 ,  327 . 
       FIG. 4B  illustrates another placement of an exemplary urinary catheter in accordance with aspects of this disclosure. In  FIG. 4B , the tumor  101  is irradiated by a radiation source  119  that is placed within the urethra  105  by an afterloader catheter  117  within the urinary catheter. With the second balloon  401  inflated, radiation can reach the tumor  101  without directly injecting the afterloader catheter  117  into the tumor  101 . The afterloader catheter  117  may also be integrated into the catheter tube  201 . 
     The electrical signals produced by external photodetectors may be processed to triangulate the position of a radiation source  119 . The urinary catheter can therefore be used to track the afterloader on a real-time basis. This location as determined by the urinary catheter system can be used as quality control feedback to the afterloader. The urinary catheter, with or without the afterloader catheter  117 , may be disposable. 
     While the present system has been described with reference to certain implementations, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present system. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from its scope. Therefore, it is intended that the present method and/or system not be limited to the particular implementations disclosed, but that the present system will include all implementations falling within the scope of the appended claims. 
     As utilized herein the terms “circuits” and “circuitry” refer to physical electronic components (i.e. hardware) and any software and/or firmware (“code”) which may configure the hardware, be executed by the hardware, and or otherwise be associated with the hardware. As used herein, for example, a particular processor and memory may comprise first “circuitry” when executing a first one or more lines of code and may comprise second “circuitry” when executing a second one or more lines of code. As utilized herein, “and/or” means any one or more of the items in the list joined by “and/or”. As an example, “x and/or y” means any element of the three-element set {(x), (y), (x, y)}. In other words, “x and/or y” means “one or both of x and y”. As another example, “x, y, and/or z” means any element of the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, “x, y and/or z” means “one or more of x, y and z”. As utilized herein, the term “exemplary” means serving as a non-limiting example, instance, or illustration. As utilized herein, the terms “e.g.,” and “for example” set off lists of one or more non-limiting examples, instances, or illustrations. As utilized herein, circuitry is “operable” to perform a function whenever the circuitry comprises the necessary hardware and code (if any is necessary) to perform the function, regardless of whether performance of the function is disabled or not enabled (e.g., by a user-configurable setting, factory trim, etc.).