Radiation Tube Backward Shielding for Off-Focal Radiation Reduction
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Solution Overview
Problem
Radiation generating apparatuses face challenges in reducing off-focal radiation, which decreases image resolution, while maintaining high radiation generation efficiency and compact size, due to the generation of off-focal radiation from backscattering electrons and heavy shielding members.
Innovation Solution
A radiation generating apparatus with a transmission type target and a tubular backward shielding member, where the target layer is separated from the base member at the periphery, and a collimator with an adjustable opening diameter is used to minimize off-focal radiation by controlling the emission angle and reducing radiation from the shielding member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a transmission type target is used to increase radiation generation efficiency, then radiation output intensity increases, but off-focal radiation from backscattering electrons increases and decreases image resolution
Solution Approach 1:
The invention extracts and removes backscattering electrons from the system by providing an electron blocking structure (shielding member) that prevents these electrons from reaching the base member. This eliminates the source of off-focal radiation while maintaining the transmission type target's high radiation generation efficiency, thus resolving the contradiction between power output and image resolution.
Solution Approach 2:
The invention introduces an intermediary component (electron blocking structure/shielding member) positioned between the target layer and the base member. This intermediary blocks backscattering electrons from causing harmful interactions with the base member, thereby preventing off-focal radiation generation while allowing the transmission type target to maintain its high radiation output capability.
2Measurement precision
If heavy shielding members are added to limit radiation emission angles, then off-focal radiation is reduced, but apparatus weight and size increase
Solution Approach 1:
The invention applies local quality by using a lightweight electron blocking structure made of materials with low atomic number (such as aluminum or plastic) rather than heavy shielding materials. The blocking structure is positioned locally at the electron source side of the target, providing precise electron blocking functionality without the weight penalty of heavy metallic shielding, thus achieving radiation directionality control with minimal weight increase.
3Measurement precision
If the target layer is separated from the base member at the periphery, then off-focal radiation is reduced, but structural complexity increases
Solution Approach 1:
The invention applies segmentation by dividing the target structure into distinct functional layers: a target layer for radiation generation and a base member for structural support. By separating these layers at the periphery and positioning the electron blocking structure between them, the design creates distinct functional zones that prevent electron-induced off-focal radiation while maintaining manufacturing feasibility through modular construction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces off-focal radiation, maintaining high radiation intensity within the focal spot and improving image resolution, while allowing for a compact and lightweight design suitable for portable medical and diagnostic applications.
Implementation Method 1
an electron emitting source having an electron emitting member, a target having a target layer receiving emission of an electron beam emitted from the electron emitting member and generating radiation
Implementation Method 2
a target having a target layer receiving emission of an electron beam emitted from the electron emitting member and generating radiation
Data Source
AI summary
A radiation generating apparatus includes a radiation generation tube including an electron emitting source having an electron emitting member, a transmission type target, a tubular backward shielding member having an electron passing hole facing the target layer at one end, located at the electron emitting source side of the transmission type target, and connected to the periphery of the base member. The radiation generating apparatus further includes a collimator having an opening for defining an angle for extracting the radiation at the opposite side of the electron emitting source side of the transmission type target, and an adjusting device connected to the collimator, and configured to vary an opening diameter of the opening, wherein the target layer has a portion separated from a connection portion of the base member and the backward shielding member at the periphery.