Characterizing Radiation Effectiveness in Ion-Beam Therapy Part II: Microdosimetric Detectors

Colautti, P.; Magrin, Giulio; Cortés‐Giraldo, M. A.; Conte, V.

doi:10.3389/fphy.2020.550458

Cited by 10 publications

(9 citation statements)

References 80 publications

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“…The dose‐mean lineal energy values are useful parameters for characterizing radiation quality. The differences and the correlations between lienal energy and LET quantities are thoroughly described in the literature 15,56 . The values of

{\bar{y}_d}\

and LET do not coincide but their comparison is a common practice which must be seen as a practical way to show a general trend of the radiation quality at different depths expressed by experimental (lineal energy) and computational (LET) quantities.…”

Section: Resultsmentioning

confidence: 99%

“…The differences and the correlations between lienal energy and LET quantities are thoroughly described in the literature. 15,56 The values of ȳd and LET do not coincide but their comparison is a common practice which must be seen as a practical way to show a general trend of the radiation quality at different depths expressed by experimental (lineal energy) and computational (LET) quantities. The dose averaged LET values (LET d ) in water, calculated by means of GATE Monte Carlo simulation (see Section 2.4), are also reported in Figure 8 for both proton and carbon ion beams.…”

Section: Resultsmentioning

confidence: 99%

“…Solid‐state detectors have the advantage of small physical sizes, the capability to cope with high‐intensity beams, and to allow for high spatial resolution 15–21 . In addition, they do not require high voltages or the use of high vacuum and gas flowing systems, and are transportable and reasonably inexpensive.…”

Section: Introductionmentioning

confidence: 99%

“…Solid-state detectors have the advantage of small physical sizes, the capability to cope with high-intensity beams, and to allow for high spatial resolution. [15][16][17][18][19][20][21] In addition, they do not require high voltages or the use of high vacuum and gas flowing systems, and are transportable and reasonably inexpensive. In comparison with silicon, synthetic single crystal diamond is a good candidate to produce detectors for both dosimetry and microdosimetry applications thanks to its outstanding properties.…”

Section: Introductionmentioning

confidence: 99%

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Diamond based integrated detection system for dosimetric and microdosimetric characterization of radiotherapy ion beams

Verona,

Barna,

Georg

et al. 2023

Medical Physics

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BackgroundIon beam therapy allows for a substantial sparing of normal tissues and higher biological efficacy. Synthetic single crystal diamond is a very good material to produce high‐spatial‐resolution and highly radiation hard detectors for both dosimetry and microdosimetry in ion beam therapy.PurposeThe aim of this work is the design, fabrication and test of an integrated waterproof detector based on synthetic single crystal diamond able to simultaneously perform dosimetric and microdosimetric characterization of clinical ion beams.MethodsThe active elements of the integrated diamond device, that is, dosimeter and microdosimeter, were both realized in a Schottky diode configuration featured by different area, thickness, and shape by means of photolithography technologies for the selective growth of intrinsic and boron‐doped CVD diamond. The cross‐section of the sensitive volume of the dosimetric element is 4 mm2 and 1 μm‐thick, while the microdosimetric one has an active cross‐sectional area of 100 × 100 μm2 and a thickness of about 6.2 μm. The dosimetric and microdosimetric performance of the developed device was assessed at different depths in a water phantom at the MedAustron ion beam therapy facility using a monoenergetic uniformly scanned carbon ion beam of 284.7 MeV/u and proton beam of 148.7 MeV. The particle flux in the region of the microdosimeter was 6·107 cm2/s for both irradiation fields. At each depth, dose and dose distributions in lineal energy were measured simultaneously and the dose mean lineal energy values were then calculated. Monte Carlo simulations were also carried out by using the GATE‐Geant4 code to evaluate the relative dose, dose averaged linear energy transfer (LETd), and microdosimetric spectra at various depths in water for the radiation fields used, by considering the contribution from the secondary particles generated in the ion interaction processes as well.ResultsDosimetric and microdosimetric quantities were measured by the developed prototype with relatively low noise (∼2 keV/μm). A good agreement between the measured and simulated dose profiles was found, with discrepancies in the peak to plateau ratio of about 3% and 4% for proton and carbon ion beams respectively, showing a negligible LET dependence of the dosimetric element of the device. The microdosimetric spectra were validated with Monte Carlo simulations and a good agreement between the spectra shapes and positions was found. Dose mean lineal energy values were found to be in close agreement with those reported in the literature for clinical ion beams, showing a sharp increase along the Bragg curve, being also consistent with the calculated LETd for all depths within the experimental error of 10%.ConclusionsThe experimental indicate that the proposed device can allow enhanced dosimetry in particle therapy centers, where the absorbed dose measurement is implemented by the microdosimetric characterization of the radiation field, thus providing complementary results. In addition, the proposed device allows for the reduction of the experimental uncertainties associated with detector positioning and could facilitate the partial overcoming of some drawbacks related to the low sensitivity of diamond microdosimeters to low LET radiation.

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{\bar{y}_d}\

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Diamond based integrated detection system for dosimetric and microdosimetric characterization of radiotherapy ion beams

Verona,

Barna,

Georg

et al. 2023

Medical Physics

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“…Such fluctuations can lead to lower absorption of the actual dose by some tumor cells or increase the incidence of complications in normal tissues during radiotherapy (Brahme 1984, Lindborg andBrahme 1990). Therefore, many studies have introduced microdosimetry theory to explore the microscopic distribution of the interaction between radiation and sensitive targets (Colautti et al 2020, Scholz et al 2020. In microdosimetry, the specific energy z is defined as the imparted energy e per unit mass m reflecting the actual energy in a given microscopic target at a consistent level of absorbed dose, D. ( ) f z D , is the probability density function of the specific energy in a microscopic volume, representing the microdosimetric distribution of energy at the absorbed dose D in the macroscopic region.…”

Section: Introductionmentioning

confidence: 99%

Microdosimetric assessment about proton spread-out Bragg peak at different depths based on the normal human mesh-type cell population model

et al. 2023

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Objective. In clinical proton therapy, the spread-out Bragg peak (SOBP) is commonly used to fit the target shape. Dose depositions at microscopic sites vary, even with a consistent absorbed dose ( D ) in SOBP. In the present study, monolayer mesh-type cell population models were developed for microdosimetric assessment at different SOBP depths. Approach. Normal human bronchial epithelial (BEAS-2B) and hepatocytes (L-O2) mesh-type cell models were constructed based on fluorescence tomography images of normal human cells. Particle transport simulation in cell populations was performed coupled with Monte Carlo software PHITS. The relationship between microdosimetry and macrodosimetry of SOBP at different depths was described by analyzing the microdosimetric indicators such as specific energy z , specific energy distribution f z , D , and relative standard deviation σ z / z ¯ within cells. Additionally, the microdosimetric distributions characteristics and their contributing factors were also discussed. Main results. The microscopic dose distribution is strongly influenced by cellular size, shape, and material. The mean specific energy z ¯ of nucleus and cytoplasm in the cell population is greater than the overall absorbed dose of the cell population model ( D p ), with a maximum z ¯ / D p of 1.1. The cellular dose distribution is different between the BEAS-2B mesh-type model and its concentric ellipsoid geometry-type model, which difference in z ¯ is about 10.3% for the nucleus and about 7.5% for the cytoplasm with the SOBP depth of 15 cm. When D = 2 Gy, the maximum z of L-O2 nucleus reaches 2.8 Gy and σ z / z ¯ is 5.1% at the mid-depth SOBP (16–18 cm); while the maximum z of the BEAS-2B nucleus reaches 2.2 Gy with only 2.7% of σ z / z ¯ . Significance. The significant variation of microdosimetric distributions of SOBP different depths indicates the necessity to use mesh-type cell population models, which have the potential to be compared with biological results and build the bio-physical model.

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The rationale for a carbon ion radiation therapy facility in Australia

Thwaites,

Prokopovich,

Garrett

et al. 2023

J of Medical Radiation Sci

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Australia has taken a collaborative nationally networked approach to achieve particle therapy capability. This supports the under‐construction proton therapy facility in Adelaide, other potential proton centres and an under‐evaluation proposal for a hybrid carbon ion and proton centre in western Sydney. A wide‐ranging overview is presented of the rationale for carbon ion radiation therapy, applying observations to the case for an Australian facility and to the clinical and research potential from such a national centre.

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Characterizing Radiation Effectiveness in Ion-Beam Therapy Part II: Microdosimetric Detectors

Cited by 10 publications

References 80 publications

Diamond based integrated detection system for dosimetric and microdosimetric characterization of radiotherapy ion beams

Diamond based integrated detection system for dosimetric and microdosimetric characterization of radiotherapy ion beams

Microdosimetric assessment about proton spread-out Bragg peak at different depths based on the normal human mesh-type cell population model

The rationale for a carbon ion radiation therapy facility in Australia

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