Curriculum Vitaes

Naoki Hayashi

  (林 直樹)

Profile Information

Affiliation
Professor, Division of Medical Physics, School of Medical Sciences, Fujita Health University
Degree
Ph.D(Nagoya University)
M.Sc.(Kanazawa University)

Researcher number
00549884
J-GLOBAL ID
201201043293710753
researchmap Member ID
B000219735

Papers

 94
  • Noriyuki Kadoya, Kazuhiro Arai, Shohei Tanaka, Yuto Kimura, Ryota Tozuka, Keisuke Yasui, Naoki Hayashi, Yoshiyuki Katsuta, Haruna Takahashi, Koki Inoue, Keiichi Jingu
    Radiological physics and technology, Sep 10, 2024  
    This study aimed to evaluate the performance for answering the Japanese medical physicist examination and providing the benchmark of knowledge about medical physics in language-generative AI with large language model. We used questions from Japan's 2018, 2019, 2020, 2021 and 2022 medical physicist board examinations, which covered various question types, including multiple-choice questions, and mainly focused on general medicine and medical physics. ChatGPT-3.5 and ChatGPT-4.0 (OpenAI) were used. We compared the AI-based answers with the correct ones. The average accuracy rates were 42.2 ± 2.5% (ChatGPT-3.5) and 72.7 ± 2.6% (ChatGPT-4), showing that ChatGPT-4 was more accurate than ChatGPT-3.5 [all categories (except for radiation-related laws and recommendations/medical ethics): p value < 0.05]. Even with the ChatGPT model with higher accuracy, the accuracy rates were less than 60% in two categories; radiation metrology (55.6%), and radiation-related laws and recommendations/medical ethics (40.0%). These data provide the benchmark for knowledge about medical physics in ChatGPT and can be utilized as basic data for the development of various medical physics tools using ChatGPT (e.g., radiation therapy support tools with Japanese input).
  • Yuya Nagake, Keisuke Yasui, Hiromu Ooe, Masaya Ichihara, Kaito Iwase, Toshiyuki Toshito, Naoki Hayashi
    Radiological Physics and Technology, 17(1) 280-287, Jan 23, 2024  Peer-reviewed
    The reference dose for clinical proton beam therapy is based on ionization chamber dosimetry. However, data on uncertainties in proton dosimetry are lacking, and multifaceted studies are required. Monte Carlo simulations are useful tools for calculating ionization chamber dosimetry in radiation fields and are sensitive to the transport algorithm parameters when particles are transported in a heterogeneous region. We aimed to evaluate the proton transport algorithm of the Particle and Heavy Ion Transport Code System (PHITS) using the Fano test. The response of the ionization chamber f Q and beam quality correction factors k Q were calculated using the same parameters as those in the Fano test and compared with those of other Monte Carlo codes for verification. The geometry of the Fano test consisted of a cylindrical gas-filled cavity sandwiched between two cylindrical walls. f Q was calculated as the ratio of the absorbed dose in water to the dose in the cavity in the chamber. We compared the f Q calculated using PHITS with that of a previous study, which was calculated using other Monte Carlo codes (Geant4, FULKA, and PENH) under similar conditions. The flight mesh, a parameter for charged particle transport, passed the Fano test within 0.15%. This was shown to be sufficiently accurate compared with that observed in previous studies. The f Q calculated using PHITS were 1.116 ± 0.002 and 1.124 ± 0.003 for NACP-02 and PTW-30013, respectively, and the k Q were 0.981 ± 0.008 and 1.027 ± 0.008, respectively, at 150 MeV. Our results indicate that PHITS can calculate the f Q and k Q with high precision.
  • Noriyuki Yanagawa, Takayuki Ishida, Toru Hirano, Tomonori Isobe, Naoki Hayashi
    Nihon Hoshasen Gijutsu Gakkai zasshi, 80(1) 79-86, 2024  
  • Noriyuki Yanagawa, Takayuki Ishida, Tohru Hirano, Tomonori Isobe, Naoki Hayashi
    Japan Journal of radiological technology, 80(1) 79-86, Jan, 2024  Invited
  • Natsuo Tomita, Naoki Hayashi, Tomoki Mizuno, Yuto Kitagawa, Keisuke Yasui, Yasunori Saito, Shuo Sudo, Seiya Takano, Nozomi Kita, Akira Torii, Masanari Niwa, Dai Okazaki, Taiki Takaoka, Daisuke Kawakita, Shinichi Iwasaki, Akio Hiwatashi
    Technical innovations & patient support in radiation oncology, 28 100221-100221, Dec, 2023  Peer-reviewed
    INTRODUCTION: In this simulation study, we examined the effects of a de-escalation strategy with a reduced dose to subclinical nodal regions in patients with human papillomavirus (HPV)-associated oropharyngeal carcinoma (OPC). METHODS: We created two patterns of intensity-modulated radiotherapy for 16 patients with HPV-associated OPC. In the standard and de-escalation plans, the initial field including elective nodal regions received 46 and 30 Gy, followed by 20 and 36 Gy to the cutdown field, respectively. Comparison metrics were set for each organ at risk (OAR). We compared these metric values and the probability of adverse effects based on the normal tissue complication probability (NTCP) model between the two plans. RESULTS: Both plans generally met the dose constraints for the targets and all OAR. Among the comparison metrics, the mean doses to the brain, pharyngeal constrictor muscle, thyroid, and skin and the dose to a 1 % volume of the skin were higher in the standard plan than in the de-escalation plan (P = 0.031, 0.007, < 0.001, < 0.001, and 0.006, respectively). NTCP analyses revealed that the probability of adverse effects in the ipsilateral parotid gland and thyroid was higher in the standard plan than in the de-escalation plan (standard vs. de-escalation plans: ipsilateral parotid gland, 6.4 % vs. 5.0 %, P = 0.016; thyroid, 3.3 % vs. 0.5 %, P < 0.001). CONCLUSIONS: A de-escalation strategy with elective nodal regions is a promising treatment to prevent a decline in the quality of life in patients with HPV-associated OPC, particularly xerostomia, dysphagia, and hypothyroidism.

Misc.

 30

Books and Other Publications

 14

Presentations

 51

Teaching Experience

 14

Research Projects

 9

作成した教科書、教材、参考書

 3
  • 件名(英語)
    診療放射線技術ガイド(第3版)
    終了年月日(英語)
    2014/04
    概要(英語)
    共著にて作成。現場で活躍する診療放射線技師にとって必要な実践的な知識を網羅する教科書である。私は放射線治療技術に関する項を担当しました。
  • 件名(英語)
    Japanese standard radiation dosimetry of absorbed dose in water for external radiotherapy
    開始年月日(英語)
    2012/09/10
    概要(英語)
    本邦の外部放射線治療における吸収線量の標準的計測法を記述する本を医学物理学会の編集メンバーとともに分担執筆した.私はラジオクロミックフィルムの章と光子線計測に関する部分を担当した.
  • 件名(英語)
    Experiment on radiological technology: basic course
    開始年月日(英語)
    2016/04/01
    概要(英語)
    診療放射線技師を養成する大学において学生実験を行うための教科書を分担執筆した.私はラジオクロミックフィルムを用いた線量計測を担当した.