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The Fantastic Journey of Gel Dosimeters: How Has the Technology Evolved from 1950 to Today?
Gel dosimeters have always been a key element in radiotherapy and safety measurement technology. Since the 1950s, scientists have been exploring how to measure the absorbed dose of radiation through colloidal systems, a process filled with amazing developments and technological changes. This article will take you back to the development history of gel dosimeters since their birth and discuss the most advanced technology currently available.
Early exploration
Gel dosimeters were originally made from radiation-sensitive chemicals that undergo fundamental changes when exposed to ionizing radiation. As early as the 1950s, researchers used color changes in dyes to explore radiation doses in colloidal systems. Then in 1957, researchers used spectroscopic measurements to study the depth dose of photons and electrons in agar gel.
When radiation strikes, the molecular structure in the colloidal system will change. This change is the basis for us to measure the absorbed dose.
Development of Fricke gel dosimeter
In 1984, Gore and other researchers demonstrated how to measure radiation-induced changes in Fricke dosimeter solutions through nuclear magnetic resonance (NMR). Their study confirmed that iron (Fe2+) ions are converted into iron (Fe3+) ions, and this conversion can be quantified by NMR relaxation rate measurements . By 1986, Appleby et al. reported that Fricke dosimeter solutions could be dispersed in a colloidal matrix to obtain three-dimensional spatial dose information using magnetic resonance imaging (MRI).
As the research deepened, the researchers found that the Fricke gel dosimeter could not maintain a stable dose distribution because ions would diffuse in the gel after radiation.
Innovation in polymer gel dosimeter
The concept of polymer gel dosimeter was first proposed in 1954. In 1961, Boni used polyacrylamide as a gamma dosimeter, and in 1992, Kenan et al. reported absorbed dose revealed by NMR longitudinal relaxation testing. In 1992, Maryanski et al. proposed a new gel dosimeter formula called BANANA, based on the polymerization of acrylamide and N,N'-dimethylacrylamide. The stability of this system was significantly higher than that of Fricke-type gel. shaped dosimeter.
The polymerization reaction of the BANANA colloidal dosimeter is initiated by free radicals generated by the radiodissociation of water, significantly improving the stability of the dose distribution.
The emergence of oxygen-free polymer gel dosimeter
In 2001, Fong et al. published a new polymer gel dosimeter called MAGIC, which improved the maneuverability of the gel dosimeter. This new gel dosimeter effectively solves the problem of oxygen inhibition and can be produced in a laboratory without a strict anaerobic environment. The main components of MAGIC polymer glue are methacrylic acid, ascorbic acid and copper. The emergence of this new formula represents a revolutionary breakthrough in gel dosimeters.
The emergence of MAGIC makes the production of gel dosimeters more flexible and greatly expands the possibilities in clinical applications.
International conferences and their impact
Since 1996, the international community has begun to pay attention to the research and application of colloidal dosimeters. Clive Baldock and L. John Schreiner discussed the appropriateness of holding a special conference on colloidal dosimeters at the conference. In 1999, the first DosGel conference was held in Kentucky, USA, with the purpose of gathering researchers and users interested in 3D radiation dose measurement technology.
This series of meetings not only promoted academic exchanges, but also promoted the clinical practice of gel dosimeter technology.
Prospects of current technology
With the advancement of radiotherapy technology, the demand for high-precision three-dimensional dose measurement methods is also rising. The research and development of various new gel dosimeters is constantly advancing to meet clinical requirements. However, further discussion and research are still needed for the widespread clinical application of gel dosimeters in the future.
We are witnessing rapid technological advancements. How will gel dosimeters continue to evolve in radiotherapy, and what new challenges and opportunities will they face?
