Tomosynthesis Irradiation Limiter Layout for Leakage Control
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Solution Overview
Problem
Existing tomosynthesis imaging apparatuses suffer from unnecessary exposure due to radiation leakage from irradiation openings corresponding to adjacent radiation tubes, which is not effectively addressed by current configurations.
Innovation Solution
The apparatus employs an irradiation field limiter with movable plate-like members that adjust the position and size of irradiation openings to align with specific radiation tubes, preventing radiation leakage by defining the irradiation field more precisely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an irradiation field limiter with irradiation openings corresponding to each radiation tube is used, then radiation leakage from adjacent tubes is prevented, but radiation leaks from openings corresponding to adjacent tubes causing unnecessary exposure
Solution Approach 1:
The patent applies the dynamics principle by making the irradiation field limiter movable rather than fixed. The limiter can shift its position to align irradiation openings with specific radiation tubes that need to be blocked. This dynamic adjustment allows the system to adapt to different imaging scenarios and prevent radiation leakage from adjacent tubes without causing unnecessary exposure by blocking all openings continuously.
Solution Approach 2:
The irradiation field limiter acts as an intermediary component between the radiation tubes and the imaging target. By introducing this movable limiting structure, the patent enables precise control over which radiation tubes can emit radiation toward the target, thereby preventing leakage from adjacent tubes while avoiding unnecessary exposure through selective positioning.
2Measurement precision
If three or more radiation tubes are brought close to each other, then the signal-noise ratio of the tomographic image is improved, but radiation leaks from irradiation openings causing unnecessary exposure
Solution Approach 1:
By making the irradiation field limiter movable, the patent enables close positioning of multiple radiation tubes (three or more) to improve signal-noise ratio, while the dynamic limiter can selectively block radiation from adjacent tubes that would otherwise leak through fixed openings. This resolves the contradiction by allowing close tube spacing for better imaging quality without the penalty of unnecessary exposure from radiation leakage.
Solution Approach 2:
The patent applies local quality by enabling different irradiation openings to have different states (open or blocked) based on which radiation tube is actively emitting. The movable limiter allows precise local control over radiation paths, permitting close tube spacing for improved signal-noise ratio while blocking leakage from specific adjacent tubes to prevent unnecessary exposure.
3Reliability
If irradiation openings are formed to correspond to each radiation tube, then the irradiation field is defined, but radiation leaks from adjacent openings
Solution Approach 1:
The movable irradiation field limiter dynamically adjusts its position to maintain proper alignment between irradiation openings and active radiation tubes. This dynamic capability ensures reliable irradiation field definition while preventing radiation leakage from adjacent openings by blocking them when their corresponding tubes are not actively emitting radiation.
Data Source
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AI summary
Provided is a tomosynthesis imaging apparatus that can prevent unnecessary exposure. Fifteen radiation tubes are arranged in a radiation source of the mammography apparatus. An irradiation field limiter includes a plate-like member having a plurality of through holes that function as irradiation openings. Adjacent through holes are arranged at an interval of one radiation tube. In the plate-like member, the position of the through holes which are irradiation openings are moved to a first set position in a case in which radiation is emitted from first radiation tubes which are some of three or more radiation tubes and a second set position in a case in which the radiation is emitted from second radiation tubes different from the first radiation tubes among the three or more radiation tubes. Therefore, one through hole is shared by two radiation tubes.