System and Method for Controlling Radiation Dose for Radiological Applications

Abstract

A system and method for reconstructing an image acquired by delivering an irradiating dose of radiation to a subject includes acquiring imaging data using a dose of irradiating radiation and selecting at least one of a plurality of mechanisms for reducing the dose that could be delivered to the subject to acquire additional imaging data. Noise is inserted into the imaging data to simulate the at least one of the plurality of mechanisms for reducing the dose that could be applied to acquire the additional imaging data to thereby generate simulated imaging data at a reduced dose of irradiating radiation. A simulated reduced dose image is reconstructed from the simulated imaging data. A method is provided for utilizing a non-local means filter adapted using a map of local noise to produce denoised medical imaging data reflecting reduced local nose levels from those in originally-acquired medical imaging data.

1 . A method for reconstructing an image acquired by delivering an irradiating dose of radiation to a subject, the method comprising:
 obtaining medical imaging data using the irradiating dose of radiation;   obtaining a map of local noise level in the medical imaging data;   utilizing a non-local means filter adapted using the map of local noise to produce denoised medical imaging data reflecting reduced local nose levels from those in the medical imaging data; and   providing a medical image of the subject from the denoised medical imaging data.   
     
     
         2 . The method of  claim 1  wherein the step of obtaining a map includes creating a simulated reduced dose image. 
     
     
         3 . The method of  claim 2  wherein the simulated reduced dose image is used as map of local noise level 
     
     
         4 . A method for reconstructing an image acquired by delivering an irradiating dose of radiation to a subject, the method comprising:
 obtaining a set of medical imaging data acquired using a dose of irradiating radiation delivered to a subject;   selecting at least one of a plurality of mechanisms for reducing the dose of irradiating radiation that could be delivered to the subject to acquire an additional set of medical imaging data;   inserting noise into the medical imaging data to simulate the at least one of the plurality of mechanisms for reducing the dose of irradiating radiation that could be applied to acquire the additional set of medical imaging data to thereby generate a simulated set of medical imaging data at a reduced dose of irradiating radiation; and   reconstructing a simulated reduced dose image from the simulated set of medical imaging data.   
     
     
         5 . The method of  claim 4  wherein the selecting includes selecting at least one of a bowtie filter mechanism for reducing the dose of radiation and automatic tube current modulation mechanism for reducing the dose of radiation. 
     
     
         6 . The method of  claim 4  wherein the inserting noise includes simulating electronic noise associated with the at least one of the plurality of mechanisms for reducing the dose of irradiating radiation. 
     
     
         7 . The method of  claim 4  further comprising utilizing the simulated reduced dose image to perform a filtering of the medical imaging data. 
     
     
         8 . The method of  claim 7  wherein the filtering includes a non-local means filter. 
     
     
         9 . The method of  claim 7  wherein the simulated reduced dose image is used as an approximation of a noise map in the filtering of the medical imaging data. 
     
     
         10 . A computed tomography (CT) imaging system comprising:
 an x-ray source configured to emit x-rays toward an object to be imaged;   a detector configured to receive x-rays that are attenuated by the object;   a data acquisition system (DAS) connected to the detector to receive an indication of received x-rays;   a computer system coupled to the DAS to receive the indication of the received x-rays and programmed to:
 obtain a set of medical imaging data acquired using a dose of irradiating radiation delivered by the x-ray source to a subject positioned between the x-ray source and the detector; 
 select at least one of a plurality of mechanisms for reducing the dose of irradiating radiation that could be delivered to the subject to acquire an additional set of medical imaging data; 
 insert noise into the medical imaging data to simulate the at least one of the plurality of mechanisms for reducing the dose of irradiating radiation that could be applied to acquire the additional set of medical imaging data to thereby generate a simulated set of medical imaging data at a reduced does of irradiating radiation; and 
 reconstruct a simulated reduced dose image from the simulated set of medical imaging. 
   
     
     
         11 . The CT imaging system of  claim 10  wherein the plurality of mechanisms for reducing the dose of irradiating radiation include at least one of a bowtie filter and automatic tube current modulation. 
     
     
         12 . The CT imaging system of  claim 10  wherein the computer system is further programmed to utilize the simulated reduced dose image to perform a filtering of the medical imaging data. 
     
     
         13 . The CT imaging system of  claim 12  wherein the simulated reduced dose image is used as an approximation of a noise map in the filtering of the medical imaging data and wherein the filtering includes a non-local means filter. 
     
     
         14 . A computed tomography (CT) imaging system comprising:
 an x-ray source configured to emit x-rays toward an object to be imaged;   a detector configured to receive x-rays that are attenuated by the object;   a data acquisition system (DAS) connected to the detector to receive an indication of received x-rays;   a computer system coupled to the DAS to receive the indication of the received x-rays and programmed to:
 obtain a set of medical imaging data using the irradiating dose of radiation; 
 obtain a map of local noise level in the medical imaging data; 
 utilize a non-local means filter adapted using the map of local noise to produce denoised medical imaging data reflecting reduced local nose levels from those in the medical imaging data; and 
 provide a medical image of the subject from the denoised medical imaging data. 
   
     
     
         15 . The CT imaging system of  claim 14  wherein the computer system is further programmed to create a simulated reduced dose image. 
     
     
         16 . The CT imaging system of  claim 15  wherein the computer system is further programmed to use the simulated reduced dose image as the map of local noise level.