Medical Physicist's Dossier · myOSL™ Chip
A short, technical dossier for the medical physicist commissioning OSL in-vivo for the first time or switching from the discontinued Landauer nanoDot. The five panels below are internal-testing QA results from the manufacturer type-test programme — the kind of charts that decide whether a detector is worth taking to your linac. Peer-reviewed validation papers (Kowalski 2025, Davis 2025) live on the Knowledge Hub.
Data on this page is reproduced from the manufacturer internal type-test programme. Saxsons Group serves as the authorised Indian distributor and can arrange on-site evaluation against your own reference dosimeters.
Measured Hp(10) vs reference dose, 0 → 1 000 mSv.
Result
R² = 0.9994 · slope 0.9007
Interpretation
Across three orders of magnitude — from background-level (sub-mSv) to accident-tier (1 Sv) — the system's response is linear with R² = 0.9994. A near-unity slope (0.9007) means a single energy-independent calibration factor recovers the reference reading; no piecewise correction needed.
What it means for your workflow
Calibrate once, trust the curve across the full operational dose range.
OSL signal (a.u.) vs delivered dose, 0 → 10 Sv (dosimeter #3520).
Result
r² = 0.9999 to 10 Sv
Interpretation
The same linear behaviour holds an order of magnitude further up, into the radiotherapy in-vivo dose regime. r² = 0.9999 from zero to 10 Sv on a single dosimeter means BeO saturation and supralinearity aren't practical concerns at clinical doses.
What it means for your workflow
Safe for in-vivo entrance/exit checks at any clinical fractionation, including SBRT-level single fractions.
(μ_en/ρ)_material / (μ_en/ρ)_tissue across 10 keV → 10 MeV photons. BeO compared against CaF₂, CaSO₄, Al₂O₃, LiF, Li₂B₄O₇ and air.
Result
Z_eff 7.21 · flat from ~50 keV upward
Interpretation
BeO's effective atomic number (7.21) sits right next to soft tissue (7.35), so the mass-energy-absorption ratio stays near unity across the entire diagnostic and therapeutic photon range. Above ~50 keV the response is essentially flat — well within ±5 %. Al₂O₃:C (Z_eff ≈ 11) over-responds 2–3× in the kV diagnostic range; BeO does not.
What it means for your workflow
No energy-dependent correction needed for routine kV/MV photon dosimetry. Drop-in replacement for Al₂O₃:C nanoDots without a workflow redesign.
Mean recovered dose at three read-out delays after a 0.35 mSv reference irradiation. Background subtracted.
Result
−0.16 % at 3 months
Interpretation
After 15 minutes the deviation from reference is −0.37 %. After one week, −0.51 %. After three months, −0.16 % — i.e. there is no statistically meaningful fading on a routine quarterly read-out cadence. Read-out scheduling is therefore a logistics question, not a measurement-accuracy question.
What it means for your workflow
Quarterly badge cycles, mailed samples, and delayed-readout protocols all fit comfortably within the system's fade tolerance.
Polar response across 60°, 90°, 120° irradiation angles for ISO N-series narrow-spectrum beams (N60 → N200) plus Cs-137 and Co-60.
Result
< 20 % drop at 90° (side)
Interpretation
Side-on irradiation reduces the indicated value by less than 20 % relative to en-face — well inside the angular-dependence band specified in IEC personal-dosimetry test protocols. Across the full N60 → Co-60 energy range the spread is consistent, so a single angular correction handles real-world badge orientations.
What it means for your workflow
Passes IEC type-test angular requirements. Realistic body-mounted use does not need a per-angle correction.
| Metric | Result | Reference |
|---|---|---|
| Linearity (0 → 1 Sv) | R² 0.9994 | Hp(10) test, slope 0.9007 |
| Linearity (0 → 10 Sv) | r² 0.9999 | extended single-dosimeter test |
| Fading (3 months) | −0.16 % | vs 0.35 mSv reference |
| Fading (1 week) | −0.51 % | σ = 1.35 % |
| Angular response (side vs front) | < 20 % | IEC type-test compliant |
| Tissue equivalence | Z_eff 7.21 | soft tissue 7.35 |
| Detector material | BeO | 4.7 × 4.7 × 0.5 mm element |
| Housing | 9.5 × 10 × 2 mm | ABS light-tight |
Independent peer-reviewed validation (Kowalski 2025 — Duke; Davis 2025 — UVA) confirms these characteristics against the discontinued Landauer nanoDot. Full citations on the Knowledge Hub.
Bring it to your linac
Saxsons Group will arrange a trial set of myOSL Chip dosimeters and a reader so your physics team can replicate the linearity, fading and angular tests above in your own QA programme — before any commitment.
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