{
  "abstract": "Range uncertainties remain a major limitation to the full clinical exploitation of proton therapy, motivating reliable in-vivo range-verification techniques. This work presents an experimental investigation of a hybrid Prompt-Gamma Imaging (PGI)--Positron-Emission Tomography (PET) concept at the isochronous cyclotron of the West German Proton Therapy Centre under clinically representative pencil-beam-scanning conditions. Because this accelerator delivers a quasi-continuous beam, a pulsed shoot-and-step structure was imposed to mimic the interruptions associated with clinical energy-layer switching. This enabled PGI during irradiation and PET and delayed Compton imaging during beam-off intervals within the same sequence. Four two-plane Compton cameras were arranged in a co-planar cross-shaped geometry around the beam isocenter. Polyethylene phantoms were irradiated with 100~MeV protons at known positions along the beam axis. Their positions were estimated from reconstructed one-dimensional profiles using supervised machine-learning models trained exclusively on Monte Carlo simulations. PET achieved the best performance, with a root-mean-square deviation of 0.8~mm, followed by PGI with 1.6~mm. Delayed Compton imaging based on e$^{+}$ annihilation photons and $^{10}$C$^{*}$ decays yielded 2.4~mm and 3.8~mm, respectively. PET retained good performance down to 1% of the original event statistics, whereas PGI became increasingly statistics-limited. These results demonstrate the complementary strengths of hybrid PGI--PET and support its development towards millimetre-scale proton-range verification under clinically relevant irradiation conditions.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.25993",
  "author_total": 11,
  "authors": [
    {
      "name": "Javier Balibrea-Correa"
    },
    {
      "name": "V. Babiano-Suarez"
    },
    {
      "name": "J. Lerendegui-Marco"
    },
    {
      "name": "P. Torres-Sánchez"
    },
    {
      "name": "I. Ladarescu"
    },
    {
      "name": "M. Pallàs"
    },
    {
      "name": "B. Brusasco"
    },
    {
      "name": "J. Wulff"
    },
    {
      "name": "C. Bäumer"
    },
    {
      "name": "A. Tarifeño-Saldivia"
    },
    {
      "name": "C. Domingo-Pardo"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fd6v7rwx32j60.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.25993",
  "fulltext_url": null,
  "id": "fd6v7rwx32j60",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.25993",
  "language": null,
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "nucl-ex"
    ],
    [
      "arxiv",
      "physics.med-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.25993",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-22",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fd6v7rwx32j60.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:39Z",
      "native_id": "2609.25993",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.25993"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.med-ph",
      "subfield": "biological-medical"
    },
    {
      "field": "physics",
      "origin": "arxiv:nucl-ex",
      "subfield": "nuclear"
    }
  ],
  "title": "Towards real-time ion range verification via hybrid Compton-PET 3D imaging at isochronous cyclotrons",
  "title_text": "Towards real-time ion range verification via hybrid Compton-PET 3D imaging at isochronous cyclotrons",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:39Z",
  "url": "https://research.draconitic.com/paper/fd6v7rwx32j60",
  "venue": "arXiv",
  "versions": []
}