Method of X-ray protection during diagnostic CT imaging
AssigneeF & L Medical Products
InventorKenneth D. Hopper
Life of this patent
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Abstract
A shield is placed on a patient's body over a secondary organ adjacent a target organ. The shield is partially transparent to x-ray radiation. A CT scan of the target organ is conducted according to conventional protocols and technical parameters. No artifacts are formed in the diagnostic portion of the CT image and there is no degradation of the diagnostic portion of the CT image. A reduction of between about 40% and about 60% in the radiation dose of the secondary organ as compared to the same CT scan made without the shield is achieved.
Claims18
A method of generating a diagnostic image of a cross section of a target patient organ located adjacent a radiosensitive secondary organ by a computed tomography scanner, the scanner having a revolvable x-ray source and x-ray sensor, said method comprising the steps of:
- (a) placing the patient between the x-ray source and the x-ray sensor of the computed tomography scanner to scan a patient cross section including the target organ and the secondary organ;
- (b) placing a shield partially transparent to x-rays over the secondary organ, the shield not extending around the entire cross section of the patient;
- (c) revolving the x-ray source and the x-ray sensor around the patient, the shield located between the x-ray source and the secondary organ for less than an entire revolution of the x-ray source around the patient;
- (d) transmitting x-rays emitted from the revolving x-ray source through the target organ, the secondary organ and the shield and to the sensor to scan the patient with the computed tomography scanner, the scanner configured to irradiate the cross section with an x-ray intensity;
- (e) absorbing x-rays passing through the shield when the shield is between the secondary organ and the x-ray source to reduce the radiation dose received by the secondary organ from the scan by between 40% and 60% of the radiation dose that would have been received by the secondary organ from a like scan made with the same x-ray intensity but without the shield;
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- (f) processing signals generated by the sensor in response to the x-rays received by the x-ray sensor during the scan, including the x-rays transmitted through the shield and the secondary organ, to generate a readable diagnostic image of the target organ.
A method for reducing the x-ray dose of a radiosensitive secondary organ of a patient from radiation emitted during a diagnostic computed tomography scan of an adjacent target organ by a computed tomography scanner comprising the steps of:
- (a) positioning the body of a patient between an x-ray source and an x-ray sensor of the computed tomography scanner;
- (b) emitting a beam of x-rays from the x-ray source through a cross section of the body including the target organ and the radiosensitive secondary organ and to the x-ray sensor, the x-ray beam having an intensity where the beam intersects the cross section of the body;
- (c) moving the x-ray source and sensor along a path extending around the body cross section so that both the target organ and the secondary organ are radiated by the x-ray beam, the path having a portion wherein the x-ray source is closest to the secondary organ, said x-ray beam comprising a first beam portion radiating the secondary organ and a second beam portion, said first beam portion less than the entire x-ray beam;
- (d) reducing the intensity of the first beam portion and not reducing the intensity of the second beam portion when the x-ray source is along said closest path portion, the reduction in intensity of the first beam portion sufficient to appreciably reduce the x-ray dose received by the secondary organ from the scan compared to an x-ray dose received by the secondary organ from a like computer tomography scan made without such reduction of intensity;
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- (e) processing signals generated by the x-ray sensor in response to x-rays received by the x-ray sensor, including the reduced intensity x-rays transmitted through the secondary organ, to generate a readable diagnostic image of the target organ.
Dependencies are inferred from the claim text.