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Medical-physics challenge from radiotherapy with FAIR
https://repo.qst.go.jp/records/75918
https://repo.qst.go.jp/records/75918d6141aef-3903-4c3b-b6ff-4b2413f15953
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2019-05-28 | |||||
| タイトル | ||||||
| タイトル | Medical-physics challenge from radiotherapy with FAIR | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Matsufuji, Naruhiro
× Matsufuji, Naruhiro× Matsufuji, Naruhiro |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | The ultra-high intensity, energy and Z (atomic number) beam produced by the FAIR accelerator is in a class of its own that will open new era. Upcoming medical-physics issues using the FAIR for radiotherapy will be cast here. High intensity The most lucid point will be the intensity. While the ordinary ion-beam therapy machine takes about 1 minute to deliver 1 Gy to a target, FAIR can do so in less than 1 second. It will realize instantaneous therapeutic shot under breath holding just like a chest X-ray examination. The instantaneous shot can be beneficious in treating moving target or paediatric patient by reducing internal margin or disusing anaesthetic or sedative applied in current radiotherapy respectively. The primal challenge in medical physics is within beam delivery. Modern active scanning magnet can sweep beam at the speed of 100 m/s [1], however; the energy-changing system and associated monitor devices is a matter of challenge. Passive beam delivery could be the alternative solution. Among them, the double-scatter system [2] coupled with a ridge filter and a compensator are made of all static devices, so the performance is in principle not limited by the beam intensity. High energy Regarding the energy, even uranium ions get to penetrate through a patient’s body by FAIR. The shooting-through irradiation with light ion beam was tried in early days when geometrical information of target and organs-at-risk inside the patient’s body was unavailable. In modern day with X-ray CT we should definitely make use of the Bragg peak. Here, high-energetic ion beam can be served as a diagnostic purpose. In the coming adaptive radiotherapy, treatment plan will be modified on the fly to adapt to the physiological change at the time of irradiation. The residual range of the penetrated ion contains important information as the integral stopping power on its trajectory. The choice of optimum ion species for the diagnostic purpose is a matter of study; heavier ion is advantageous regarding multiple scattering but causes more frequent nuclear fragmentation. The target for measurement such as primary or secondary radiation is also interesting theme together with the choice of measurement method. In addition to conventional Time-Of-Flight measurement or full-stop bulk scintillator, new approach such as Cherenkov-ring detector may be a choice. High Z The use of ultra-heavy ion for therapy is a matter of concern. From dose localization viewpoint, ions heavier than neon is regarded not appropriate in current fashion due to less prominent Bragg peak by more frequent nuclear fragmentation. So-called overkill phenomenon also diminishes the biological effectiveness at the Bragg peak. Here, mini-beam (grid) irradiation [3] may bring alternative figure of merit. By delivering ion beam as sparsely placed mini beams of less than one mm in width, it is expected normal tissue at the entrance area can be spared in case the tissue has significant volume effect. The highly heterogeneous dose distribution accepted there may also allow for the use of ultra-heavy ion beams. Spread to related fields The radiotherapy with FAIR will promote various studied in related fields. For example, biological effectiveness of therapeutic ion beam is estimated in the treatment planning based on the microscopic energy deposition by the incident ions both in Germany [4] and Japan [5]. Radial dose distribution called as track structure of ions at FAIR range spreads far over the cells or even tissue. It is interesting to examine the current biological models are still valid to handle the biological effectiveness at FAIR. The intensity (dose-rate) dependency is also needed for clarification for both acute cellular response as well as late tissue response such as carcinogenesis. |
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| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | 1st meeting of the international biophysics collaboration | |||||
| 発表年月日 | ||||||
| 日付 | 2019-05-22 | |||||
| 日付タイプ | Issued | |||||
