The physics of proton therapy

Newhauser, Wayne D.; Zhang, R.

doi:10.1088/0031-9155/60/8/r155

Cited by 489 publications

(371 citation statements)

References 208 publications

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“…Surviving fractions (SF) were fitted according to the linear-quadratic model SF=exp-(αD-βD 2 ). No statistically significant difference between cellular survival to laser-driven and conventionally accelerated proton beams was observed (Figure 4).…”

Section: Resultsmentioning

confidence: 99%

“…The use of charged particles significantly reduces the dose absorbed by normal tissues due to their inverse dose-depth deposition profile as described by the Bragg curve. Their superior ballistic properties are thus the physical pillar justifying hadrontherapy as the eligible treatment for deepseated tumours and/or close to organs at risk [2]. Heavier charged particles such as carbon ions exhibit a higher radiobiological effectiveness than protons or photons, due to their denser ionization event pattern through matter, whereby highly clustered DNA lesion sites arise.…”

Section: The Rationale For Laser-driven Cancer Hadrontherapymentioning

confidence: 99%

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The radiobiology of laser-driven particle beams: focus on sub-lethal responses of normal human cells

et al. 2017

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A: Accelerated proton beams have become increasingly common for treating cancer. The need for cost and size reduction of particle accelerating machines has led to the pioneering investigation of optical ion acceleration techniques based on laser-plasma interactions as a possible alternative. Laser-matter interaction can produce extremely pulsed particle bursts of ultra-high dose rates (≥ 10 9 Gy/s), largely exceeding those currently used in conventional proton therapy. Since biological effects of ionizing radiation are strongly affected by the spatio-temporal distribution of DNA-damaging events, the unprecedented physical features of such beams may modify cellular and tissue radiosensitivity to unexplored extents. Hence, clinical applications of laser-generated particles need thorough assessment of their radiobiological effectiveness. To date, the majority of studies have either used rodent cell lines or have focussed on cancer cell killing being local tumour control the main objective of radiotherapy. Conversely, very little data exist on sub-lethal cellular effects, of relevance to normal tissue integrity and secondary cancers, such as premature cellular senescence. Here, we discuss ultra-high dose rate radiobiology and present preliminary 1Corresponding author.

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Section: Resultsmentioning

confidence: 99%

Section: The Rationale For Laser-driven Cancer Hadrontherapymentioning

confidence: 99%

The radiobiology of laser-driven particle beams: focus on sub-lethal responses of normal human cells

et al. 2017

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“…For each material in (Table ), the mean proton stopping power was calculated for protons with initial kinetic energy over the energy range from E 0 = 100 MeV to E f = 200 MeV (not including the Bragg peak) with 1000 equal energy steps, without tracking the particles, with the following equation:

\bar{S_{m}} = \frac{\int_{E_{0}}^{E_{f}} S_{m} (E) d E}{\int_{E_{0}}^{E_{f}} d E}

where S m is the restricted stopping power calculated with the Geant4's Bethe‐Bloch equation via the GetDEDX method in the G4EmCalculator class using a high (effectively infinite) production cut. The RSP of each material was then calculated by dividing the evaluated Eq.…”

Section: Methodsmentioning

confidence: 99%

The effect of beam purity and scanner complexity on proton CT accuracy

et al. 2017

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Purpose To determine the dependence of the accuracy in reconstruction of relative stopping power (RSP) with proton computerized tomography (pCT) scans on the purity of the proton beam and the technological complexity of the pCT scanner using standard phantoms and a digital representation of a pediatric patient. Methods The Monte Carlo method was applied to simulate the pCT scanner, using both a pure proton beam (uniform 200 MeV mono-energetic, parallel beam) and the Northwestern Medicine Chicago Proton Center (NMCPC) clinical beam in uniform scanning mode. The accuracy of the simulation was validated with measurements performed at NMCPC including reconstructed RSP images obtained with a preclinical prototype pCT scanner. The pCT scanner energy detector was then simulated in three configurations of increasing complexity: an ideal totally absorbing detector, a single stage detector and a multi-stage detector. A set of 15 cm diameter water cylinders containing either water alone or inserts of different material, size, and position were simulated at 90 projection angles (4° steps) for the pure and clinical proton beams and the three pCT configurations. A pCT image of the head of a detailed digital pediatric phantom was also reconstructed from the simulated pCT scan with the prototype detector. Results The RSP error increased for all configurations for insert sizes under 7.5 mm in radius, with a sharp increase below 5 mm in radius, attributed to a limit in spatial resolution. The highest accuracy achievable using the current pCT calibration step-phantom and reconstruction algorithm, calculated for the ideal case of a pure beam with totally absorbing energy detector, was 1.3% error in RSP for inserts of 5 mm radius or more, 0.7 mm in range for the 2.5 mm radius inserts, or better. When the highest complexity of the scanner geometry was introduced, some artifacts arose in the reconstructed images, particularly in the center of the phantom. Replacing the step-phantom used for calibration with a wedge phantom led to RSP accuracy close to the ideal case, with no significant dependence of RSP error on insert location or material. The accuracy with the multi-stage detector and NMCPC beam for the cylindrical phantoms was 2.2% in RSP error for inserts of 5 mm radius or more, 0.7 mm in range for the 2.5 mm radius inserts, or better. The pCT scan of the pediatric phantom resulted in mean RSP values within 1.3% of the reference RSP, with a range error under 1 mm, except in exceptional situations of parallel incidence on a boundary between low and high density. Conclusions The pCT imaging technique proved to be a precise and accurate imaging tool, rivalling the current x-rays based techniques, with the advantage of being directly sensitive to proton stopping power rather than photon interaction coefficients. Measured and simulated pCT images were obtained from a wobbled proton beam for the first time. Since the in-silico results are expected to accurately represent the prototype pCT, upcoming measurements using the wedge p...

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“…The proton therapy is of great interest due to its superior spatial dose distribution to a tumor (Newhauser and Zhang 2015). The proton beam can be used as a tool to treat the eye cancer, lung cancer, and head cancer etc.…”

Section: Description Of the Superconducting Coilsmentioning

confidence: 99%

“…The proton beam therapy has the unique merits mentioned above that makes it particularly attractive for the treatment of pediatric cancers, cancers in the eye, cancer of skull base, and spine cancer (Efstathiou et al 2013; Levin et al 2005). The 250 MeV superconducting cyclotron for proton therapy is being designed due to the advantages with high magnetic field, low operation costs and more compactness compared with the conventional magnet technology (Kang et al 2010; Newhauser and Zhang 2015; Choi et al 2010). The design goals of the superconducting cyclotron include high reliability, low activation, easy maintenance and easy to use.…”

Section: Introductionmentioning

confidence: 99%

Conceptual design of the superconducting magnet for the 250 MeV proton cyclotron

2016

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BackgroundThe superconducting cyclotron is of great importance to treat cancer parts of the body. To reduce the operation costs, a superconducting magnet system for the 250 MeV proton cyclotron was designed to confirm the feasibility of the superconducting cyclotron.FindingsThe superconducting magnet system consists of a pair of split coils, the cryostat and a pair of binary high temperature superconductor current leads. The superconducting magnet can reach a central magnetic field of about 1.155 T at 160 A. The three GM cryocooler with cooling capacities of 1.5 W at 4.5 K and 35 W at 50 K and one GM cryocooler of 100 W at 50 K were adopted to cool the superconducting magnet system through the thermosiphon technology.ConclusionThe four GM cryocoolers were used to cool the superconducting magnet to realize zero evaporation of the liquid helium.

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The physics of proton therapy

Cited by 489 publications

References 208 publications

The radiobiology of laser-driven particle beams: focus on sub-lethal responses of normal human cells

The radiobiology of laser-driven particle beams: focus on sub-lethal responses of normal human cells

The effect of beam purity and scanner complexity on proton CT accuracy

Conceptual design of the superconducting magnet for the 250 MeV proton cyclotron

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