Facility Overview for a Proton Beam Treatment Center

Lesyna, David

doi:10.1177/15330346070060s407

Cited by 16 publications

(13 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Data was collected in the Gantry 1 treatment room of the James M. Slater MD Proton Therapy and Research Center at the Loma Linda University Medical Center (LLUMC). (18) Comparisons of diode data with ion chamber or film were conducted using our standard nominal radiosurgery energies of 127 MeV and 157 MeV through a single-stage scattering system, corresponding to a range of 9.7 and 15 cm in water, respectively. The single-stage scattering system provides a maximum field size of 4 cm diameter, with collimation provided via a dedicated SRS cone that attaches to the end of the proton nozzle.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of the dosimetric properties of a diode detector for small field proton radiosurgery

McAuley

Teran

Slater

et al. 2015

J Applied Clin Med Phys

View full text Add to dashboard Cite

The small fields and sharp gradients typically encountered in proton radiosurgery require high spatial resolution dosimetric measurements, especially below 1–2 cm diameters. Radiochromic film provides high resolution, but requires postprocessing and special handling. Promising alternatives are diode detectors with small sensitive volumes (SV) that are capable of high resolution and real‐time dose acquisition. In this study we evaluated the PTW PR60020 proton dosimetry diode using radiation fields and beam energies relevant to radiosurgery applications. Energies of 127 and 157 MeV (9.7 to 15 cm range) and initial diameters of 8, 10, 12, and 20 mm were delivered using single‐stage scattering and four modulations (0, 15, 30, and 60 mm) to a water tank in our treatment room. Depth dose and beam profile data were compared with PTW Markus N23343 ionization chamber, EBT2 Gafchromic film, and Monte Carlo simulations. Transverse dose profiles were measured using the diode in "edge‐on" orientation or EBT2 film. Diode response was linear with respect to dose, uniform with dose rate, and showed an orientation‐dependent (i.e., beam parallel to, or perpendicular to, detector axis) response of less than 1%. Diode vs. Markus depth‐dose profiles, as well as Markus relative dose ratio vs. simulated dose‐weighted average lineal energy plots, suggest that any LET‐dependent diode response is negligible from particle entrance up to the very distal portion of the SOBP for the energies tested. Finally, while not possible with the ionization chamber due to partial volume effects, accurate diode depth‐dose measurements of 8, 10, and 12 mm diameter beams were obtained compared to Monte Carlo simulations. Because of the small SV that allows measurements without partial volume effects and the capability of submillimeter resolution (in edge‐on orientation) that is crucial for small fields and high‐dose gradients (e.g., penumbra, distal edge), as well as negligible LET dependence over nearly the full the SOBP, the PTW proton diode proved to be a useful high‐resolution, real‐time metrology device for small proton field radiation measurements such as would be encountered in radiosurgery applications.PACS numbers: 87.56.‐v, 87.56.jf, 87.56.Fc

show abstract

Section: Methodsmentioning

confidence: 99%

Evaluation of the dosimetric properties of a diode detector for small field proton radiosurgery

McAuley

Teran

Slater

et al. 2015

J Applied Clin Med Phys

View full text Add to dashboard Cite

show abstract

“…This system was installed on one of the research beam-lines available at LLUMC and was tuned to deliver an SPE-like proton radiation dose of 1 Gy at a dose-rate of approximately 0.5 Gy/h. An in-house clinical modulator wheel was used to deliver a uniform dose as a function of depth, while a range shifter degraded the beam to 110 MeV at the inside of the irradiation chamber as previously described (Coutrakon et al 1991, Lesyna 2007). The large field of this system allowed for the irradiation of up to four ferrets at any one time.…”

Section: Methodsmentioning

confidence: 99%

Mechanism of hypocoagulability in proton-irradiated ferrets

Krigsfeld

Savage

Sanzari

et al. 2013

International Journal of Radiation Biology

View full text Add to dashboard Cite

Purpose To determine the mechanism of proton radiation-induced coagulopathy. Material and methods Ferrets were exposed to either solar particle event (SPE)-like proton radiation at a predetermined dose rate of 0.5 Gray (Gy) per hour (h) for a total dose of 0 or 1 Gy. Blood was collected pre- and post-irradiation for a complete blood cell count or a soluble fibrin concentration analysis, to determine whether coagulation activation had occurred. Tissue was stained with an anti-fibrinogen antibody to confirm the presence of fibrin in blood vessels. Results SPE-like proton radiation exposure resulted in coagulation cascade activation, as determined by increased soluble fibrin concentration in blood from 0.7 – 2.4 at 3 h, and 9.9 soluble fibrin units (p < 0.05) at 24 h post-irradiation and fibrin clots in blood vessels of livers, lungs and kidneys from irradiated ferrets. In combination with this increase in fibrin clots, ferrets had increased prothrombin time and partial thromboplastin time values post-irradiation, which are representative of the extrinsic/intrinsic coagulation pathways. Platelet counts remained at pre-irradiation values over the course of 7 days, indicating that the observed effects were not platelet-related, but instead likely to be due to radiation-induced effects on secondary hemostasis. White blood cell (WBC) counts were reduced in a statistically significant manner from 24 h through the course of the seven-day experiment. Conclusions SPE-like proton radiation results in significant decreases in all WBC counts as well as activates secondary hemostasis; together, these data suggest severe risks to astronaut health from exposure to SPE radiation.

show abstract

“…This treatment room is fitted with a 6‐degree‐of‐freedom robotic patient positioner and associated 2D orthogonal imaging system17 to aid in alignment of the patient and, in this case, the experimental setup (Fig. 4).…”

Section: Methodsmentioning

confidence: 99%

Initial testing of a pixelated silicon detector prototype in proton therapy

Wroe

McAuley

Teran

et al. 2017

J Applied Clin Med Phys

View full text Add to dashboard Cite

As technology continues to develop, external beam radiation therapy is being employed, with increased conformity, to treat smaller targets. As this occurs, the dosimetry methods and tools employed to quantify these fields for treatment also have to evolve to provide increased spatial resolution. The team at the University of Wollongong has developed a pixelated silicon detector prototype known as the dose magnifying glass (DMG) for real‐time small‐field metrology. This device has been tested in photon fields and IMRT. The purpose of this work was to conduct the initial performance tests with proton radiation, using beam energies and modulations typically associated with proton radiosurgery. Depth dose and lateral beam profiles were measured and compared with those collected using a PTW parallel‐plate ionization chamber, a PTW proton‐specific dosimetry diode, EBT3 Gafchromic film, and Monte Carlo simulations. Measurements of the depth dose profile yielded good agreement when compared with Monte Carlo, diode and ionization chamber. Bragg peak location was measured accurately by the DMG by scanning along the depth dose profile, and the relative response of the DMG at the center of modulation was within 2.5% of that for the PTW dosimetry diode for all energy and modulation combinations tested. Real‐time beam profile measurements of a 5 mm 127 MeV proton beam also yielded FWHM and FW90 within ±1 channel (0.1 mm) of the Monte Carlo and EBT3 film data across all depths tested. The DMG tested here proved to be a useful device at measuring depth dose profiles in proton therapy with a stable response across the entire proton spread‐out Bragg peak. In addition, the linear array of small sensitive volumes allowed for accurate point and high spatial resolution one‐dimensional profile measurements of small radiation fields in real time to be completed with minimal impact from partial volume averaging.

show abstract

Facility Overview for a Proton Beam Treatment Center

Cited by 16 publications

References 3 publications

Evaluation of the dosimetric properties of a diode detector for small field proton radiosurgery

Evaluation of the dosimetric properties of a diode detector for small field proton radiosurgery

Mechanism of hypocoagulability in proton-irradiated ferrets

Initial testing of a pixelated silicon detector prototype in proton therapy

Contact Info

Product

Resources

About