Characterization of a synthetic single crystal diamond Schottky diode for radiotherapy electron beam dosimetry

Venanzio, C. Di; Marinelli, M.; Milani, E.; Prestopino, G.; Verona, C.; Falco, M.D.; Bagalà, P.; Santoni, Riccardo; Pimpinella, M.

doi:10.1118/1.4774360

Cited by 53 publications

(49 citation statements)

References 35 publications

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“…Markus detector measurements agree with E Diode measurements in the bremsstrahlungs region. A similar effect, but to a lesser extent, can be observed in the publication from Venanzio et al, (15) though it is not discussed in their paper. One explanation for this behavior is that, where diamond detectors show very similar response to electron and photon radiation, both the E Diode as well as the Markus detector might overrespond to the bremsstrahlungs radiation in the electron beam, therefore slightly overestimating the percent dose in the bremsstrahlungs region.…”

Section: Resultssupporting

confidence: 70%

“…In recent years, Marco Marinelli, Gianluca Verona‐Rinati and their team from the Industrial Engineering Department of Rome Tor Vergata University in Italy have published several studies on the dosimetric characteristics of synthetic single crystal diamond detectors (SCDDs) in a Schottky diode configuration 14 , 15 . They tested their SCDDs as radiotherapy dosimeters for small field photon fields of energies up to 10 MV and for electron fields from 6 MeV to 20 MeV.…”

Section: Introductionmentioning

confidence: 99%

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Clinical radiation therapy measurements with a new commercial synthetic single crystal diamond detector

Laub

Crilly

2014

J Applied Clin Med Phys

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A commercial version of a synthetic single crystal diamond detector (SCDD) in a Schottky diode configuration was recently released as the new type 60019 microDiamond detector (PTW‐Freiburg, Germany). In this study we investigate the dosimetric properties of this detector to independently confirm that findings from the developing group of the SCDDs still hold true for the commercial version of the SCDDs. We further explore if the use of the microDiamond detector can be expanded to high‐energy photon beams of up to 15 MV and to large field measurements. Measurements were performed with an Elekta Synergy linear accelerator delivering 6, 10, and 15 MV X‐rays, as well as 6, 9, 12, 15, and 20 MeV electron beams. The dependence of the microdiamond detector response on absorbed dose after connecting the detector was investigated. Furthermore, the dark current of the diamond detector was observed after irradiation. Results are compared to similar results from measurements with a diamond detector type 60003. Energy dependency was investigated, as well. Photon depth‐dose curves were measured for field sizes 3×3,10×10, and 30×30.15emcm2. PDDs were measured with the Semiflex type 31010 detector, microLion type 31018 detector, P Diode type 60016, SRS Diode type 60018, and the microDiamond type 60019 detector (all PTW‐Freiburg). Photon profiles were measured at a depth of 10 cm. Electron depth‐dose curves normalized to the dose maximum were measured with the 14×14.15emcm2 electron cone. PDDs were measured with a Markus chamber type 23343, an E Diode type 60017 and the microDiamond type 60019 detector (all PTW‐Freiburg). Profiles were measured with the E Diode and microDiamond at half of D90,D90,D70, and D50 depths and for electron cone sizes of 6×6.15emcm2, 14×14.15emcm2, and 20×20.15emcm2. Within a tolerance of 0.5% detector response of the investigated detector was stable without any preirradiation. After preirradition with approximately 250 cGy the detector response was stable within 0.1%. A dark current after irradiation was not observed. The microDiamond detector shows no energy dependence in high energy photon or electron dosimetry. Electron PDD measurements with the E Diode and microDiamond are in good agreement. However, compared to E Diode measurements, dose values in the bremsstrahlungs region are about 0.5% lower when measured with the microDiamond detector. Markus detector measurements agree with E Diode measurements in the bremsstrahlungs region. For depths larger than dmax, depth‐dose curves of photon beams measured with the microDiamond detector are in close agreement to those measured with the microLion detector for small fields and with those measured with a Semiflex 0.125 cc ionization chamber for large fields. Differences are in the range of 0.25% and less. For profile measurements, microDiamond detector measurements agree well with microLion and P Diode measurements in the high‐dose region of the profile and the penumbra region. For areas outside the open field, P Diode measurements are about 0.5%–1.0% highe...

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Section: Resultssupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Clinical radiation therapy measurements with a new commercial synthetic single crystal diamond detector

Laub

Crilly

2014

J Applied Clin Med Phys

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“…17 The device was incapsulated in the same PTW Freiburg housing used for the unshielded Silicon diode (PTW Diode E model 60017). Diamond sensitive volume is a cylinder 2.2 mm in diameter and about 1 μm thick, placed 0.8 mm from the detector tip.…”

Section: B Detectors and Phantomsmentioning

confidence: 99%

“…These SCDDs have been tested as radiotherapy dosimeters with different beam qualities (photons from 60 Co to 10 MV and electrons from 6 MeV to 18 MeV). 6,[15][16][17] In the present work, the dosimetric properties of a SCDD were tested by studying point dose measurements during volumetric modulated arc therapy (VMAT) treatments. This delivery technique poses stringent requirements on the dosimetric performances of a detector due to the modulation of the dose rate achieved changing the velocity of the gantry and of the collimator leaves.…”

Section: Introductionmentioning

confidence: 99%

A synthetic diamond diode in volumetric modulated arc therapy dosimetry

et al. 2013

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Purpose: The aim of this work is to investigate the behavior of a single crystal diamond diode (SCDD) for volumetric modulated arc therapy (VMAT) dose verifications. This delivery technique is one of the most severe test of a dosimeter performance due to the modulation of the dose rate achieved by simultaneously changing the velocity of the gantry and the position of the collimator leaves. The performed measurements with VMAT photon beams can therefore contribute to an overall global validation of the device to be used in dose distribution verifications. Methods:The SCDD response to 6 MVRX has been tested and compared with reference ionization chambers and treatment planning system (TPS) calculations in different experiments: (a) measurements of output factors for small field sizes (square fields of side ranging between 8 mm and 104 mm) by SCDD and A1SL ionization chamber; (b) angular dependence evaluation of the entire experimental set-up by SCDD, A1SL, and Farmer ionization chambers; and (c) acquisition of dose profiles for a VMAT treatment of a pulmonary disease in latero-lateral and gantry-target directions by SCDD and A1SL ionization chamber. Results: The output factors measured by SCDD favorably compare with the ones obtained by A1SL, whose response is affected by the lack of charged particle equilibrium and by averaging effect when small fields are involved. From the experiment on angular dependence, a good agreement is observed among the diamond diode, the ion chambers, and the TPS. In VMAT profiles, the absorbed doses measured by SCDD and A1SL compare well with the TPS calculated ones. An overall better agreement is observed in the case of the diamond dosimeter, which is also showing a better accuracy in terms of distance to agreement in the high gradient regions. Conclusions: Synthetic diamond diodes, whose performance were previously studied for conformal and IMRT radiotherapy techniques, were found to be suitable detectors also for dosimetric measurements in volumetric arc therapy treatments.

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“…The suitability of this smallvolume detector for dosimetry in standard clinical beams was already investigated, showing very good dosimetric properties in comparison with reference detectors (Almaviva et al 2008, Di Venanzio et al 2013. In addition, such SCDDs were characterized in small photon beams (down to 1 × 1 cm 2 ), whose dosimetry is challenging (Ciancaglioni et al 2012, Pimpinella et al 2012a, 2012b.…”

Section: Introductionmentioning

confidence: 99%

Radiotherapy electron beams collimated by small tubular applicators: characterization by silicon and diamond diodes

Bagalà¹,

Venanzio²,

Falco³

et al. 2013

Phys. Med. Biol.

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High-energy electron beams generated by linear accelerators, typically in the range 6 to 20 MeV, are used in small field sizes for radiotherapy of localized superficial tumors. Unshielded silicon diodes (Si-D) are commonly considered suitable detectors for relative dose measurements in small electron fields due to their high spatial resolution. Recently, a novel synthetic single crystal diamond diode (SCDD) showed suitable properties for standard electron beams and small photon beams dosimetry. The aim of the present study is twofold: to characterize 6 to 15 MeV small electron beams shaped by using commercial tubular applicators with 2, 3, 4 and 5 cm diameter and to assess the dosimetric performance under such irradiation conditions of the novel SCDD dosimeter by comparison with commercially available dosimeters, namely a Si-D and a plane-parallel ionization chamber. Percentage depth dose curves, beam profiles and output factors (OFs) were measured. A good agreement among the dosimeters was observed in all of the performed measurements. As for the tubular applicators, two main effects were evidenced: (i) OFs larger than unity were measured for a number of field sizes and energies, with values up to about 1.3, that is an output 30% greater than that obtained at the 10 × 10 cm 2 reference field; (ii) for each diameter of the tubular applicator a noticeable increase of the OF values was observed with increasing beam energy, up to about 100% in the case of the smaller applicator. This OF behavior is remarkably different from what typically observed for small blocked fields having the same size and energy as those used in this study. OFs for tubular applicators depend considerably on the field size, so interpolation is unadvisable to predict the linear accelerator output for such applicators whereas reliable high-resolution detectors, as the

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Characterization of a synthetic single crystal diamond Schottky diode for radiotherapy electron beam dosimetry

Cited by 53 publications

References 35 publications

Clinical radiation therapy measurements with a new commercial synthetic single crystal diamond detector

Clinical radiation therapy measurements with a new commercial synthetic single crystal diamond detector

A synthetic diamond diode in volumetric modulated arc therapy dosimetry

Radiotherapy electron beams collimated by small tubular applicators: characterization by silicon and diamond diodes

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