Evidence map›Paper›PMID 40364526›Full record

ArticleJournal of radiation research2025

Regional disparities in IMRT utilization in Japan: analysis of trends and associated medical resources from 2015 to 2019†.

Keisuke Tamari, Yuna Kumoyama, Hodaka Numasaki, Yuichi Akino, Kazuhiko Hayashi, Takero Hirata, Shotaro Tatekawa, Yutaka Takahashi, Shinichi Shimizu, Kazuhiko Ogawa

Abstract read
In one paragraph

Article in Journal of radiation research, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
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

2 citing papers in PubMed.

  1. Article
  2. Geographic access to radiotherapy facilities in Japan.Journal of radiation research · 2026
    Article
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

10 authors.

Keisuke TamariDepartment of Radiation Oncology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.ORCID 0000-0002-2290-1905
Yuna KumoyamaDepartment of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Osaka, 565-0871, Japan.
Hodaka NumasakiDepartment of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Osaka, 565-0871, Japan.ORCID 0000-0002-4427-4316
Yuichi AkinoDepartment of Radiation Oncology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.ORCID 0000-0002-7215-3458
Kazuhiko HayashiDepartment of Radiation Oncology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Takero HirataDepartment of Radiation Oncology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Shotaro TatekawaDepartment of Radiation Oncology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Yutaka TakahashiDepartment of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Osaka, 565-0871, Japan.
Shinichi ShimizuDepartment of Carbon Ion Radiotherapy, Osaka University Graduate School of Medicine, Suita, Osaka, 565-0871, Japan.
Kazuhiko OgawaDepartment of Radiation Oncology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.

Funding

JSPS KAKENHI 23K07178
6 · The paper itself

Abstract

Intensity-modulated radiation therapy (IMRT) uses intensity-modulated photon beams from multiple directions to achieve conformal dose delivery to a target with a complex shape while reducing the dose to organs at risk. We analyzed the trends in IMRT utilization rates across Japanese prefectures from 2015 to 2019 and investigated their relationship with medical resources. Data from the National Database of Health Insurance Claims and the Japanese Society for Radiation Oncology Structure Survey were analyzed. IMRT utilization rates and medical resources (radiation oncologists, medical physicists, radiation technologists, and IMRT-capable linear accelerators) were assessed for all 47 prefectures. A mixed-model analysis was employed to examine the relationship between IMRT utilization rates and medical resources. IMRT utilization increased from 16.4% in 2015 to 22.0% in 2019, with significant regional disparities (range, <10% to >30%). Mixed-model analysis revealed that the number of IMRT-capable linear accelerators (estimate = 0.073, P < 0.01) and radiation oncologists (estimate = 0.032, P = 0.04) was significantly associated with higher IMRT utilization rates. Medical physicists and radiation technologists showed no significant association with IMRT utilization rates. Although the use of IMRT has increased in Japan, substantial regional disparities persist. Increasing the number of IMRT-capable linear accelerators and radiation oncologists may be the most effective strategy to improve equitable access to IMRT in Japan.

Indexed as

Healthcare DisparitiesHealth ResourcesRadiotherapy, Intensity-ModulatedHumansJapanintensity-modulated radiation therapyJapanmedical resourcesregional disparity

Identifiers

PMID40364526
PMCPMC12151010

What OpenQuestion holds

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Registered trials

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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.