Highlights
- •Highly segmented pcCVD diamond detectors are fabricated using a pulsed laser grafitization technique.
- •All size pixels have dose rate linearity, repeatability and response homogeneity.
- •Small beam profile measurements with 3D detectors depend on the pixel size.
- •Small pixel beam profiles are in good agreement with PTW microDiamond and IBA SFD silicon diode.
Abstract
Purpose:
Small photon beams used in radiotherapy techniques have inherent characteristics of
charge particle disequilibrium and high-dose gradient making accurate dosimetry for
such fields very challenging. By means of a 3D manufacturing technique, it is possible
to create arrays of pixels with a very small sensitive volume for radiotherapy dosimetry.
We investigate the impact of 3D pixels size on absorbed dose sensitivity, linearity
of response with dose rate, reproducibility and beam profile measurements.
Methods:
Diamond detectors with different pixel sizes have been produced in the 3DOSE experiment
framework. To investigate the pixels size impact, they were tested using an Elekta
Synergy LINAC. Dose rate dependence, absorbed dose sensitivity, reproducibility and
beam profile measurement accuracy have been investigated and compared with PTW 60019
and IBA SFD reference dosimeters.
Results:
All of the 3D pixels had a linear and reproducible response to the dose rate. The
sensitivity of a pixel decreases with its size, although even the smallest pixel has
a high absorbed dose sensitivity (15 nC/Gy). The penumbra width measured with the
smallest pixel size was consistent with the PTW microDiamond and differed by 0.2 mm
from the IBA SFD diode.
Conclusions:
The study demonstrates that variation in pixel size do not affect the linearity of
response with dose rate and the reproducibility of response. Due to the 3D geometry,
the absorbed dose sensitivity of the detector remains high even for the smallest pixel,
furthermore the pixel size was demonstrated to be of fundamental importance in the
measurement of beam profiles.
Keywords
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Physica Medica: European Journal of Medical PhysicsAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Diamond detectors for radiotherapy X-Ray small beam dosimetry.Front Phys. 2021; 9https://doi.org/10.3389/fphy.2021.632299
- A comparison of the quality assurance of four dosimetric tools for intensity modulated radiation therapy.Radiol Oncol. 2015; 49: 307-313https://doi.org/10.1515/raon-2015-0021
- Characterization and clinical evaluation of a novel 2D detector array for conventional and flattening filter free (FFF) IMRT pre-treatment verification.Z Medizinische Physik. 2018; 28: 134-141https://doi.org/10.1016/j.zemedi.2017.08.003
- The use of pantherpix pixel detector in radiotherapy QA.Phys Medica. 2021; 82: 332-340https://doi.org/10.1016/j.ejmp.2021.01.072
- Is the PTW 60019 micro diamond a suitable candidate for small field reference dosimetry?.Phys Med Biol. 2017; 62: 7036-7055https://doi.org/10.1088/1361-6560/aa7e59
- Present limitations of CVD diamond detectors for IMRT applications.Nucl Instrum Methods Phys Res A. 2007; 583: 195-203https://doi.org/10.1016/j.nima.2007.08.186
- Polycrystalline diamond detectors with three-dimensional electrodes.Nucl Instrum Methods Phys Res A. 2015; 796: 42-46https://doi.org/10.1016/j.nima.2015.03.041
- Investigation of 3D diamond detector dosimetric characteristics.J Instrum. 2018; 13: P06006https://doi.org/10.1088/1748-0221/13/06/P06006
- Three-dimensional diamond detectors: charge collection efficiency of graphitic electrodes.Appl Phys Lett. 2013; 103: 233507https://doi.org/10.1063/1.4839555
- Influence of temperature on the response of high-quality polycrystalline diamond detectors.Nucl Instrum Methods Phys Res A. 2007; 570: 303-307https://doi.org/10.1016/j.nima.2006.09.030
- Solid state integrating dosimeters.in: Radiation dosimetry. Vol. 2. second ed. Accademic Press, New York1966
- An investigation of the operating characteristics of two PTW diamond detectors in photon and electron beams.Med Phys. 2002; 29: 248-254https://doi.org/10.1118/1.1446101
- Intercalibration of a polycrystalline 3D diamond detector for small field dosimetry.Nucl Instrum Methods Phys Res A. 2020; 958: 162730https://doi.org/10.1016/j.nima.2019.162730
- Dosimetry of small static fields used in external photon beam radiotherapy: Summary of TRS-483, the IAEA–AAPM international code of practice for reference and relative dose determination.Med Phys. 2018; 45https://doi.org/10.1002/mp.13208
- A methodological approach to reporting corrected small field relative outputs.Radiother Oncol. 2013; 109: 350-355https://doi.org/10.1016/j.radonc.2013.10.002
- Large-area segmented polycrystalline CVD diamond for dose mapping in advanced radiotherapy techniques.in: 2016 IEEE nuclear science symposium, medical imaging conference and room-temperature semiconductor detector workshop. IEEE, 2016: 1-4https://doi.org/10.1109/NSSMIC.2016.8069394
Article info
Publication history
Published online: September 18, 2022
Accepted:
September 12,
2022
Received in revised form:
September 1,
2022
Received:
January 31,
2022
Identification
Copyright
© 2022 Associazione Italiana di Fisica Medica e Sanitaria. Published by Elsevier Ltd. All rights reserved.
