Computerized lab test on error analysis

Harrison, David; Pitre, J. M.

doi:10.1119/1.2341419

Cited by 4 publications

(2 citation statements)

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“…Uncertainties are propagated to x iso using standard techniques for uncorrelated uncertainties (see, for example, Ref. [30]). For variable F, which is a linear combination of uncorrelated variables A and B, with standard deviations σ A and σ B, it holds that…”

Section: Error Analysismentioning

confidence: 99%

Beam Position Projection Algorithms in Proton Pencil Beam Scanning

Nesteruk,

Bradley,

Kooy

et al. 2024

Cancers

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Beam position uncertainties along the beam trajectory arise from the accelerator, beamline, and scanning magnets (SMs). They can be monitored in real time, e.g., through strip ionization chambers (ICs), and treatments can be paused if needed. Delivery is more reliable and accurate if the beam position is projected from monitored nozzle parameters to the isocenter, allowing for accurate online corrections to be performed. Beam position projection algorithms are also used in post-delivery log file analyses. In this paper, we investigate the four potential algorithms that can be applied to all pencil beam scanning (PBS) nozzles. For some combinations of nozzle configurations and algorithms, however, the projection uses beam properties determined offline (e.g., through beam tuning or technical commissioning). The best algorithm minimizes either the total uncertainty (i.e., offline and online) or the total offline uncertainty in the projection. Four beam position algorithms are analyzed (A1–A4). Two nozzle lengths are used as examples: a large nozzle (1.5 m length) and a small nozzle (0.4 m length). Three nozzle configurations are considered: IC after SM, IC before SM, and ICs on both sides. Default uncertainties are selected for ion chamber measurements, nozzle entrance beam position and angle, and scanning magnet angle. The results for other uncertainties can be determined by scaling these results or repeating the error propagation. We show the propagation of errors from two locations and the SM angle to the isocenter for all the algorithms. The best choice of algorithm depends on the nozzle length and is A1 and A3 for the large and small nozzles, respectively. If the total offline uncertainty is to be minimized (a better choice if the offline uncertainty is not stable), the best choice of algorithm changes to A1 for the small nozzle for some hardware configurations. Reducing the nozzle length can help to reduce the gantry size and make proton therapy more accessible. This work is important for designing smaller nozzles and, consequently, smaller gantries. This work is also important for log file analyses.

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Section: Error Analysismentioning

confidence: 99%

Beam Position Projection Algorithms in Proton Pencil Beam Scanning

Nesteruk,

Bradley,

Kooy

et al. 2024

Cancers

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“…Early in their first year they take a required computerised test on error analysis. 2 A variety of fitters, graphers, etc. are available in support of our laboratory program; this usage is optional but the overwhelming majority of our students regularly use these tools.…”

Section: Introductionmentioning

confidence: 99%

The Physical Pendulum in an Advanced Undergraduate Course in Mechanics

Douglas

Harrison

Shepherd

et al. 1994

Computers in Physics

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We have been using a series of computer-based problem sets on the physical pendulum in our third year undergraduate course in classical mechanics for three years. The problem sets investigate the physics of this system in ways not easily accessible without this technology, and explore various algorithms for solving mechanics problems in a Hamiltonian formulation. We shall describe some of our successes and failures in developing this package.

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Trends in computer applications in science assessment

Kumar

Helgeson

1995

J Sci Educ Technol

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Computerized lab test on error analysis

Cited by 4 publications

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Beam Position Projection Algorithms in Proton Pencil Beam Scanning

Beam Position Projection Algorithms in Proton Pencil Beam Scanning

The Physical Pendulum in an Advanced Undergraduate Course in Mechanics

Trends in computer applications in science assessment

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