Is the PTW 60019 microDiamond a suitable candidate for small field reference dosimetry?

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Radiotherapy Physics

Background:

• Accurate dosimetry in small radiation fields is crucial for modern radiotherapy techniques.
• The PTW microDiamond (MD) dosimeter is investigated for its potential in small field reference dosimetry.
• Previous studies have shown varying results regarding the performance of diamond detectors in small fields.

Purpose of the Study:

• To systematically study the output factors (OF) of the PTW microDiamond (MD) dosimeter in small fields.
• To evaluate the suitability of the MD for small field reference dosimetry.
• To compare the MD's performance with PTW silicon diodes (Si-D) and validate Monte Carlo (MC) models.

Main Methods:

• Ten MDs were calibrated under 60Co irradiation.
• OF measurements were performed in 6 MV photon beams using CyberKnife M6, Varian DHX, and Elekta Synergy linacs.
• Monte Carlo (MC) simulations were used to calculate beam-quality correction factors ([Formula: see text]) and small field output correction factors ([Formula: see text]) for MD and Si-D.

Main Results:

• High reproducibility of dosimetric properties was observed among the ten MDs.
• Experimental [Formula: see text] values agreed within 1% with MC-calculated ones.
• Output correction factors were obtained within +0.7% and -1.4% down to 5 mm field sizes, showing good agreement with MC and Si-D results.

Conclusions:

• The PTW microDiamond dosimeter exhibits reproducible response and is validated by MC modeling.
• Accurate reference dosimetry is feasible using the MD for field sizes as small as 5 mm.
• The study confirms the MD's suitability for small field dosimetry applications in radiotherapy.