Improved simultaneous LET and dose measurements in proton beams of clinical relevancy using Al2O3:C OSL detectors

Published: 15 December 2021| Version 1 | DOI: 10.17632/7b52nxhxbv.1


Measurements of optically stimulated luminescence detectors (OSLDs) irradiated with protons at a wide range of doses and linear energy transfers (LETs), along with Monte Carlo simulations of the experiments to demonstrate the LET measurement capabilities of Al2O3:C. The data is used to produce the results presented in the paper titled "Improved simultaneous LET and dose measurements in proton beams of clinical relevancy using Al2O3:C optically stimulated luminescence detectors", herein referred to as the "paper". Four irradiations were used for the experiments and simulated as detailed in the paper in table 1: * field "d1" being the dose calibration * field "f1", a 70 MeV single energy layer * field "f2", a small spread-out Bragg peak (SOBP) * field "f3", a wider SOBP Data provided in this repository are labelled according to these fields (d1, f1, f2, or f3). Three types of data files are given, where the data structure is descried in the section below: 1) the raw zipped OSL data after the OSLDs were read out with the Risoe reader in pulsed mode. The data are stored according to the field names above and can be processed with e.g. the R Luminescence package or the Risoe Software. 2) a data frame "OSLD_Al2O3C_df.xlsx" where the OSLD data has been processed and split into UV and blue emissions. Each line with the OSLD information further show the irradiation parameter, e.g. information about the readout time for the fading analysis, OSLD position along the central beam axis, field name, and OSLD package name to group the data. 3) the Monte Carlo LET and dose simulations are provided in "Monte_Carlo_dataframes.xlsx". The names of the four spread sheets refer to the field names defined above and in table 1 in the paper.


Steps to reproduce

The OSLDs were irradiated in groups of 4-6 and packaged with a unique label, e.g. "B18". Hence, all OSLDs irradiated in the same package can be identified through the label. 1) Structure of the raw data files: The raw data files in the zip files are identified through these labels, which can be related to the experimental conditions and Monte Carlo simulations through the data frame "OSLD_Al2O3C_df.xlsx". The sequence files (*.SEQ) denote whether the OSLD readout was of the proton irradiation (first readout) or after the reference irradiation. 2) Structure of "OSLD_Al2O3C_df.xlsx" Each line of this data frame is the readout of an OSLD where the columns provide the information required to process the data: "target" indicates which irradiation the OSLD was a part of, e.g. dose calibration "d1" "depth_cm" gives the depth in cm in PMMA where the OSLD was placed "sample_name" gives the label name of the OSLDs, i.e. it can be used as a key to group the OSLDs irradiated in the same package "delay_hours" gives the time in hours from irradiation until the OSLD was read out. "IC_dose_Gy" gives the dose in Gy measured by the ionization chamber placed next to the OSLD "Blue", "UV", "Total" states the signal intensity $S$ (photon count) of the OSLD from the proton irradiation "*_ref" indicates the signal intensity $S_R$ of the read out of the reference electron irradiation in the reader "*_S_SR" indicates the S/S_R ratio, i.e. the ratio of the proton readout $S$ divided by the reference readout $S_R$ E.g., grouping all OSLDs called "B18" (with target "d1", i.e. the dose calibration) and aggregating according to its mean value, would give, say, the average UV/blue ratio for an irradiation of 1.106 Gy in a 230 MeV proton beam with 2.04 cm buildup. 3) Structure of "Monte_Carlo_dataframes.xlsx": The columns denote the depth in PMMA in units of cm (z_cm), the dose-averaged LET in units of keV/um, the fluence-averaged LET in units of keV/um, the relative dose deposition, the standard deviation (k=1) of the fluence-averaged LET in units of keV/um, and the standard deviation (k=1) of the dose-averaged LET in units of keV/um, respectively. If one would look up the fluence-average LET for the OSLDs labelled "B18" as in the example above, one can open the spread sheet with the target "d1", and look up the f-LET at a depth of 2.04 cm (e.g. by interpolation).


Paul Scherrer Institut


Natural Sciences, Protontherapy, Radiation Physics