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Record W2901210090 · doi:10.1002/mp.13283

Characterization of a plastic scintillating detector for the Small Animal Radiation Research Platform (<scp>SARRP</scp>)

2018· article· en· W2901210090 on OpenAlexafffund
Christopher Johnstone, François Therriault‐Proulx, Luc Beaulieu, Magdalena Bazalova‐Carter

Bibliographic record

VenueMedical Physics · 2018
Typearticle
Languageen
FieldPhysics and Astronomy
TopicAdvanced Radiotherapy Techniques
Canadian institutionsUniversité LavalCentre hospitalier universitaire de QuébecUniversity of Victoria
FundersNatural Sciences and Engineering Research Council of CanadaCanada Research Chairs
KeywordsScintillatorDosimetryKermaDosimeterIonization chamberOpticsMaterials scienceCalibrationBeam (structure)Proton therapyDetectorAbsorbed doseMonte Carlo methodNuclear medicineSensitivity (control systems)Dose profilePhysicsIonizationMedicine

Abstract

fetched live from OpenAlex

Purpose The purpose of this study was to characterize a small plastic scintillator developed for high resolution, real‐time dosimetry of therapy and imaging x‐ray beams delivered by an image‐guided small animal irradiator. Materials and Methods A 1 mm diameter, 1 mm long polystyrene BCF‐60 scintillating fiber dosimeter was characterized with 220 kVp therapy and 40, 50, 60, 70, and 80 kVp imaging beams on the Small Animal Research Platform (SARRP). Scintillator output, sensitivity (charge per unit dose), linearity, and 0.2‐mm resolution beam profile measurements were performed. A validated in‐house Monte Carlo (MC) model of the SARRP was used to compute detailed energy spectra at locations of dosimetry, and validated scintillator measurement with MC simulations. Mass energy‐absorption coefficients from the National Institute of Standards and Technology (NIST) tables convolved with MC‐derived spectra were used in conjunction with Birks ionization quenching factors to correct scintillator output. An air kerma calibration method was employed to correct scintillator output for in‐air beam profile measurements with open, 5 × 5, and 3 × 3 mm2 square field sizes, and compared to MC simulations. Results Scintillator dose response showed excellent linearity (R2 ≥ 0.999) for all sensitivity measurements, including output as a function of tube current. Detector sensitivity was 2.41 μC Gy−1 for the 220 kVp therapy beam, and it ranged from 1.21 to 1.32 μC Gy−1 for the 40–80 imaging beams. Percentage difference in sensitivity between the therapy and imaging beams before sensitivity correction and after using the Birks quenching factors were 52.3% and 10.2%, respectively. Percentage differences between the therapy and imaging beam sensitivities after using the air kerma calibration method for in‐air measurements was excellent and below 0.3%. In‐air beam profile measurements agreed to MC simulations within a mean difference of 2.4% for the 5 × 5 and 3 × 3 mm2 field sizes, however, the scintillator showed signs of volume averaging at the penumbra edges. Conclusions A small plastic scintillator was characterized for therapy and imaging energies of a small animal irradiator, with output corrected for using an in‐house MC model of the irradiator. The characterization of the scintillator detector system for small fields presents steps toward implementing real‐time measurements for quality assurance and small animal treatment and imaging dose verification.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.001
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.001
Threshold uncertainty score0.005

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.001
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0010.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.001

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.039
GPT teacher head0.335
Teacher spread0.295 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations18
Published2018
Admission routes2
Has abstractyes

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