KCl:Eu2+ Storage Phosphor Dosimeter for Reusable Radiation Dose Mapping
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Solution Overview
Problem
Conventional radiation dosimetry methods in radiation therapy are limited by the unreliability of radiographic film and ionization chambers, which are not suitable for multidimensional dose mapping and are not reusable, leading to a need for a quantitative, high-resolution, and reusable dosimeter for quality assurance in radiation therapy.
Innovation Solution
A radiation dosimeter using a storage phosphor with a europium-doped potassium chloride (KCl:Eu2+) active layer of less than 10 μm thickness, which can be reused multiple times and provides accurate, multidimensional dose measurement by emitting photons upon optical stimulation, allowing for precise calibration and verification of radiation doses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radiographic film is used for radiation dosimetry, then dose measurement can be performed, but the film cannot be reused and requires sensitometric curve calibration for each measurement
Solution Approach 1:
The storage phosphor plate can be reused multiple times by erasing the accumulated dose information through optical stimulation, allowing the same detector to be recovered and used for subsequent measurements without degradation of performance
Solution Approach 2:
The invention creates a digital copy of the dose distribution information stored in the phosphor plate, which can be read out, analyzed, and stored electronically without consuming the physical detector, enabling repeated measurements with the same hardware
2Measurement precision
If ionization chambers are used for radiation dosimetry, then quantitative dose measurement is achieved, but they cannot be used for multidimensional dose mapping
Solution Approach 1:
The storage phosphor plate transitions from a single-point measurement approach to a two-dimensional array of measurement points, allowing simultaneous capture of dose distribution across the entire radiation field in the form of an image
3Loss of information
If radiographic film is used for radiation dosimetry, then dose distribution can be visualized, but quantitative calibration is unreliable due to film batch and processor variations
Solution Approach 1:
The invention replaces the chemical processing system (film developers and processors) with an optical readout system using lasers or LEDs to stimulate the phosphor plate, eliminating variability introduced by chemical processing conditions
Solution Approach 2:
The dose information is captured as trapped electrons in the phosphor crystal lattice, creating a stable digital record that can be read out multiple times without degradation, replacing the fragile chemical image in film
4Reliability
If conventional dosimeters are used, then radiation dose can be measured, but signal fading and sensitivity loss occur over multiple uses
Solution Approach 1:
The phosphor plate erases accumulated dose information through optical stimulation at the end of each measurement cycle, resetting the detector for the next use without physical degradation or signal fading
Solution Approach 2:
The phosphor plate automatically erases its own signal through exposure to ambient light or deliberate optical stimulation, eliminating the need for separate reset procedures or replacement after each use
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 KCl:Eu2+ dosimeter offers improved radiation hardness, linear dose response, and reduced energy dependence, enabling accurate and reliable measurement of radiation doses, with minimal signal fading and sensitivity loss over multiple uses, making it suitable for clinical applications.
Implementation Method 1
The storage phosphor has a europium-doped potassium chloride active layer with an effective thickness of less than about 10 μm
Implementation Method 2
The storage phosphor is optically stimulated to emit photons
Data Source
AI summary
Radiation dosimeters containing thin KCl:Eu2+ storage phosphors for quantifying and/or verifying the dose of radiation applied during radiation therapy. Methods for measuring the amount of radiation applied from a source of radiation and methods for treating a patient having a cancerous tumor are also provided.