(Tuesday, 7/16/2019) 10:00 AM - 10:30 AM
Room: Exhibit Hall | Forum 7
Purpose: To investigate the radiological properties of a novel storage phosphor material KCl:Eu2+ in proton radiation fields.
Methods: KCl and EuCl3.6H2O powders were mixed and micronized simultaneously, in a spiral jet miller at 6.5 bars of pressure, to a europium molar concentration of 0.3%. The powders were then annealed at 375°C over 3h, pressed at 2200lbs for 3mins into 6mm diameter, 1mm thick chips, and sintered at 710°C over an additional 3h. Their radiological properties in proton beams were then tested for by irradiating these pellets with a Mevion S250 synchrocyclotron proton therapy unit using a field of 15cm range, 10cm modulation (SOBP) and at a depth of 10 cm in solid water, i.e. in the middle of the aforementioned SOBP. The chips were then readout optically by photostimulating them 17h post-irradiation with a 2mW, 594nm He-Ne laser, with intensity measurements carried out using a photomultiplier tube that is coupled to a lock-in amplifier.
Results: KCl:Eu2+ chips demonstrate good dose linearity from a dose range of 0Gy to 10Gy. They are also verified to be dose rate independent, from 83 MU/min to 583 MU/min. The photostimulated luminescence intensity of the samples stabilize at 13 hours post-irradiation. The readout signal as measured by our optical setup shows a stable 1% signal drop per readout, with very low (<1%) signal variation during the active laser time.
Conclusion: Data collected shows that KCl:Eu2+ is a good, reliable dosimeter for proton dosimetry at therapeutic doses, with a strong, stable signal and a high signal-to-noise ratio. Large-area fabrication using either tape casting or physics vapor deposition will enable a two-dimensional high resolution dosimeter for proton therapy use including IMPT.
Keywords
Not Applicable / None Entered.
Taxonomy
TH- External Beam- Particle therapy: Proton therapy - instrumentation
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