Cristin-resultat-ID: 1932109
Sist endret: 7. september 2021, 14:50
Resultat
Poster
2021

Neutron-based in-vivo range verification in proton therapy

Bidragsytere:
  • Kristian Smeland Ytre-Hauge
  • Sara Margareta Cecilia Pilskog
  • Kyrre Skjerdal
  • Janne Syltøy og
  • Ilker Meric

Presentasjon

Navn på arrangementet: NACP Symposium 2021
Sted: Digital konferanse
Dato fra: 10. mai 2021
Dato til: 13. mai 2021

Arrangør:

Arrangørnavn: NACP

Om resultatet

Poster
Publiseringsår: 2021

Beskrivelse Beskrivelse

Tittel

Neutron-based in-vivo range verification in proton therapy

Sammendrag

Introduction: Uncertainties in the proton range is currently a limitation in treatment delivery of proton therapy, leading to non-ideal field arrangements and increased treatment margins. In-vivo range verification such as prompt gamma imaging suffers from limited counting statistics, making reliable range verification during treatment challenging. Detection of secondary fast neutrons has been proposed as a supplement or alternative to existing range verification techniques. In this contribution, we present the first investigation of neutron-based in-vivo range verification applied to clinical treatment plans. Materials and Methods: A detector concept consisting of a hydrogen-rich converter followed by two position sensitive detectors was implemented in the FLUKA Monte Carlo (MC) simulations and applied in simulation of monoenergetic proton pencil beams in water and an intensity modulated proton therapy (IMPT) plan for prostate cancer. Secondary neutron production rates and distribution in water and in the patient were recorded. Furthermore, secondary neutrons were tracked in the MC simulations and detected for reconstruction of the neutron production distribution in the patient. The achievable statistics for range verification were evaluated considering different detector sizes and positioning relative to the patient. Finally, the neutron distributions from MC-ground truth and from reconstruction were used to estimate range landmarks which can be correlated to the primary proton range. The effect on the neutron distribution of introducing a 3 mm range shift was also evaluated. Results: For the IMPT plan, the neutron production rate across all pencil beams was 0.09 neutrons per primary proton. For the highest energies, production rates up to 0.15 neutrons per primary proton were observed. For monoenergetic protons in water, neutron production rates ranged from 0.03 for 100 MeV protons to 0.18 for 230 MeV protons. Neutron detection rates increased linearly with detector area, and for the patient case, placing the detector in the optimal position, slightly distal (and lateral) to the Bragg peak increased the number of detected neutrons by 16% compared to placing the detector directly laterally to the Bragg peak position. A 3 mm shift in range introduced to the treatment plan could effectively be detected in the MC-based neutron detection profiles. Conclusion: Secondary neutrons produced in IMPT can be used to monitor the proton beam range during treatment.

Bidragsytere

Kristian Smeland Ytre-Hauge

  • Tilknyttet:
    Forfatter
    ved Institutt for fysikk og teknologi ved Universitetet i Bergen

Sara Margareta Cecilia Pilskog

  • Tilknyttet:
    Forfatter
    ved Avdeling for kreftbehandling og medisinsk fysikk ved Helse Bergen HF - Haukeland universitetssykehus

Kyrre Skjerdal

  • Tilknyttet:
    Forfatter
    ved Institutt for fysikk og teknologi ved Universitetet i Bergen
  • Tilknyttet:
    Forfatter
    ved Institutt for datateknologi, elektroteknologi og realfag ved Høgskulen på Vestlandet

Janne Syltøy

  • Tilknyttet:
    Forfatter
    ved Universitetet i Bergen

Ilker Meric

  • Tilknyttet:
    Forfatter
    ved Institutt for datateknologi, elektroteknologi og realfag ved Høgskulen på Vestlandet
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