Evidence map›Paper›PMID 36439436›Full record

ArticleFrontiers in oncology2022

Collimating individual beamlets in pencil beam scanning proton therapy, a dosimetric investigation.

Jason Holmes, Jiajian Shen, Samir H Patel, William W Wong, Robert L Foote, Martin Bues, Wei Liu

Open access · goldAbstract read
In one paragraph

Article in Frontiers in oncology, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing papers in PubMed
0.5field-weighted citation impact, top 34% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

4 citing papers in PubMed, 3 citations in OpenAlex.

  1. Use of apertures in single-energy pristine Bragg peak FLASH radiotherapy.Journal of applied clinical medical physics · 2026
    Article
  2. Review
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors at 3 institutions in 1 country.

Jason HolmesDepartment of Radiation Oncology, Mayo Clinic, Phoenix, AZ, United States.
Jiajian ShenDepartment of Radiation Oncology, Mayo Clinic, Phoenix, AZ, United States.
Samir H PatelDepartment of Radiation Oncology, Mayo Clinic, Phoenix, AZ, United States.
William W WongDepartment of Radiation Oncology, Mayo Clinic, Phoenix, AZ, United States.
Robert L FooteDepartment of Radiation Oncology, Mayo Clinic, Rochester, MN, United States.
Martin BuesDepartment of Radiation Oncology, Mayo Clinic, Phoenix, AZ, United States.
Wei LiuDepartment of Radiation Oncology, Mayo Clinic, Phoenix, AZ, United States.
WinnMed · USMayo Clinic in Florida · USMayo Clinic in Arizona · US

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

The purpose of this work is to investigate collimating individual proton beamlets from a dosimetric perspective and to introduce a new device concept, the spot scanning aperture (SSA). The SSA consists of a thin aperture with a small cylindrical opening attached to a robotics system, which allows the aperture to follow and align with individual beamlets during spot delivery. Additionally, a range shifter is incorporated (source-side) for treating shallow depths. Since the SSA trims beamlets spot by spot, the patient-facing portion of the device only needs to be large enough to trim a single proton beamlet. The SSA has been modelled in an open-source Monte-Carlo-based dose engine (MCsquare) to characterize its dosimetric properties in water at depths between 0 and 10 cm while varying the following parameters: the aperture material, thickness, distance to the water phantom, distance between the aperture and attached range shifter, and the aperture opening radius. Overall, the SSA greatly reduced spot sizes for all the aperture opening radii that were tested (1 - 4 mm), especially in comparison with the extended range shifter (ranger shifter placed at 30 cm from patient); greater than 50% when placed less than 10 cm away from the patient at depths in water less than 50 mm. The peak to entrance dose ratio and linear energy transfer was found to depend on the thickness of the aperture and therefore the aperture material. Neutron production rates were also investigated and discussed.

Indexed as

dynamic collimationlateral dose resolutionlateral penumbrapencil beam scanning (PBS)spot size

Identifiers

PMID36439436
PMCPMC9692234
OpenAlexW4309182063

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.