Tissue-equivalent materials used to develop phantoms in radiation dosimetry: A review

Yadav, Neha; Singh, Manisha; Mishra, Shashwat

doi:10.1016/j.matpr.2021.06.359

Cited by 6 publications

(3 citation statements)

References 19 publications

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“…The radiation dose measurement simulation and experimental tests in phantoms provide quality assurance for radiation therapy treatment [21,22]. The phantoms are formed by special materials and represent the equivalent human body in geometrical details and the approximate tissue composition.…”

Section: Phantoms In Medical and Health Physicsmentioning

confidence: 99%

“…The effective water atomic number closely approximates the effective atomic number of human tissues. Moreover, water phantoms proved to be valuable for acquiring beam profiles and measuring radiation doses, and they played a crucial role in the commissioning and quality assurance testing of linear accelerators and treatment planning systems [22].…”

Section: Phantoms In Medical and Health Physicsmentioning

confidence: 99%

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Simulation Dosimetry Studies for FLASH Radiation Therapy (RT) with Ultra-High Dose Rate (UHDR) Electron Beam

Gazis,

Bignami,

Trachanas

et al. 2024

QuBS

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FLASH-radiotherapy (RT) presents great potential as an alternative to conventional radiotherapy methods in cancer treatment. In this paper, we focus on simulation studies for a linear particle accelerator injector design using the ASTRA code, which permits beam generation and particle tracking through electromagnetic fields. Space charge-dominated beams were selected with the aim of providing an optimized generated beam profile and accelerator lattice with minimized emittance. The main results of the electron beam and ultra-high dose rate (UHDR) simulation dosimetry studies are reported for the FLASH mode radiobiological treatment. Results for the percentage depth dose (PDD) at electron beam energies of 5, 7, 15, 25, 50, 100 MeV and 1.2 GeV for Poly-methyl-methacrylate (PMMA) and water phantom vs. the penetration depth are presented. Additionally, the PDD transverse profile was simulated for the above energies, delivering the beam to the phantom. The simulation dosimetry results provide an UHDR electron beam under the conditions of the FLASH-RT. The performance of the beam inside the phantom and the dose depth depends on the linear accelerator beam’s energy and stability.

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Section: Phantoms In Medical and Health Physicsmentioning

confidence: 99%

Section: Phantoms In Medical and Health Physicsmentioning

confidence: 99%

Simulation Dosimetry Studies for FLASH Radiation Therapy (RT) with Ultra-High Dose Rate (UHDR) Electron Beam

Gazis,

Bignami,

Trachanas

et al. 2024

QuBS

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“…For instance, phantoms are commonly used to obtain standard measurements of spatial resolution, sensitivity, and contrast recovery. [15][16][17] In fields such as oncology, specialized phantoms are even used as surrogates for lesion detectability, 18,19 dosimetry verification, 20 and computer-aided diagnosis (CAD). 21,22 As such, the design and composition of phantoms varies depending on the imaging modality and clinical application.…”

Section: Introductionmentioning

confidence: 99%

Development of the quantitative PET prostate phantom (Q3P) for improved quality assurance of ¹⁸F‐PSMA PET imaging in metastatic prostate cancer

Fedrigo,

Coope,

Rahmim

et al. 2024

Medical Physics

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BackgroundPhantoms are commonly used to evaluate and compare the performance of imaging systems given the known ground truth. Positron emission tomography (PET) scanners are routinely validated using the NEMA image quality phantom, in which lesions are modeled using 10 to 37 mm fillable spheres. The NEMA phantom neglects, however, to model focal (3–10‐mm), high‐uptake lesions that are increasingly observed in prostate‐specific membrane antigen (PSMA) PET images. PSMA‐targeting radiopharmaceuticals allow for enhanced detection of metastatic prostate cancers. As such, there is significant need to develop an updated phantom which considers both the quantitative and lesion detectability of this new paradigm in oncological PET imaging.PurposeIn this work, we present the Quantitative PET Prostate Phantom (Q3P); a portable and modular phantom that can be used to improve and harmonize imaging protocols for 18F‐PSMA PET scans.MethodsA one‐piece cylindrical phantom was designed effectively in two halves, which we call modules. Module 1 was designed to mimic lesions in the presence of background, and Module 2 mimicked very high contrast conditions (i.e., very low background) that can be observed in 18F‐PSMA PET scans. Shell‐less radioactive spheres (3–16‐mm) were cast using epoxy resin mixed with sodium‐22 (22Na), a long half‐life positron emitter with positron range similar to 18F. To establish realistic lesion contrast, the 22Na spheres were mounted in a cylindrical chamber that can be filled with an 18F background (module 1). Thirteen exchangeable spherical cavity inserts (3–37‐mm) were machined in two parts and solvent welded together, and filled with 18F (50 kBq/mL) to model lesions with very high contrast (module 2). Five 2.5‐min PET scans were acquired on a 5‐ring GE Discovery MI PET/CT scanner (General Electric, USA). Lesions were segmented using 41% of SUVmax fixed thresholding (41% FT) and recovery coefficients (RCs) were computed from 5 noise realizations.ResultsThe manufactured phantom is portable (5.7 kg) and scan preparation takes less than 40 min. The total 22Na activity is 250 kBq, allowing it to be shipped as an exempt package under International Atomic Energy Agency (IAEA) regulations. Recovery coefficients, computed using PSF modeling and no post‐reconstruction smoothing, were 130.3% (16 mm), 147.1% (10 mm), 87.2% (6 mm), and 7.0% (3 mm) for RCmax, which decreased to 91.1% (16 mm), 90.6% (10 mm), 53.2% (6 mm), and 3.6% (3 mm) for RCmean in the 22Na spheres. Comparatively, 18F sphere recovery was 110.7% (17 mm), 123.6% (10 mm), 106.5% (7 mm), and 23.3% (3 mm) for RCmax, which was reduced to 76.7% (17 mm), 77.7% (10 mm), 66.8% (7 mm), and 13.5% (3 mm), for RCmean.ConclusionsA standardized imaging phantom was developed for lesion quantification assessment in 18F‐PSMA PET images. The phantom is configurable, providing users with the opportunity to modify background activity levels or sphere sizes according to clinical demands. Distributed to the community, the Q3P phantom has the potential to enable better assessment of lesion quantification and harmonization of 18F‐PSMA PET imaging, which may lead to more robust predictive metrics and better outcome prediction in metastatic prostate cancer.

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Evaluating the Kerma coefficients relevant to various water-equivalent materials at different photon energies

Abdi,

Baghani,

Shamsabadi

2024

Nuclear Engineering and Technology

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Tissue-equivalent materials used to develop phantoms in radiation dosimetry: A review

Cited by 6 publications

References 19 publications

Simulation Dosimetry Studies for FLASH Radiation Therapy (RT) with Ultra-High Dose Rate (UHDR) Electron Beam

Simulation Dosimetry Studies for FLASH Radiation Therapy (RT) with Ultra-High Dose Rate (UHDR) Electron Beam

Development of the quantitative PET prostate phantom (Q3P) for improved quality assurance of ¹⁸F‐PSMA PET imaging in metastatic prostate cancer

Evaluating the Kerma coefficients relevant to various water-equivalent materials at different photon energies

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Tissue-equivalent materials used to develop phantoms in radiation dosimetry: A review

Cited by 6 publications

References 19 publications

Simulation Dosimetry Studies for FLASH Radiation Therapy (RT) with Ultra-High Dose Rate (UHDR) Electron Beam

Simulation Dosimetry Studies for FLASH Radiation Therapy (RT) with Ultra-High Dose Rate (UHDR) Electron Beam

Development of the quantitative PET prostate phantom (Q3P) for improved quality assurance of 18F‐PSMA PET imaging in metastatic prostate cancer

Evaluating the Kerma coefficients relevant to various water-equivalent materials at different photon energies

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Development of the quantitative PET prostate phantom (Q3P) for improved quality assurance of ¹⁸F‐PSMA PET imaging in metastatic prostate cancer