Select your region or country.
高时间性能 γ 射线探测器
探测器概念
切连科夫辐射因为能提高正电子发射断层扫描专用探测器的时间分辨率而受到关注。由于切伦科夫光子在 1 ps 的量级内迅速发射，因此与基于闪烁体的探测器相比，该探测器的时序性能将得到增强。以前，人们采用不发射闪烁体光子的单体切伦科夫辐射体来抑制辐射体中的反射。然而，重建 γ 射线的相互作用位置是具有挑战性的，因为 γ 射线与辐射体相互作用时发射的切伦科夫光子数量最多只有 30 个。作为光电检测器，使用了具有单独读出功能的高密度光电检测器阵列，以提取切伦科夫光子的所有时间和空间信息。
■特点
单体切伦科夫辐射体
→最大限度地提高切伦科夫辐射的时序性能
单独读出
→从几个切伦科夫光子获得所有时间和空间信息
光电检测器的必要规格
我们进行了蒙特卡洛模拟 [刊文 1]。根据模拟，我们发现对光电检测器的要求是高密度和良好的单光子时间分辨率 (SPTR)。例如，SPTR 必须优于 σ = 40 ps，才能获得 100 ps 半峰全宽 (FWHM) 的符合时间分辨率 (CTR)。
此外，我们还研究了深度学习在提高所提出的探测器的位置分辨率方面的潜在能力 [刊文 2]。
实验验证
使用 MCP-PMT (R3809) 高速光电检测器测量 CTR 的实验。MCP-PMT 的 SPTR 为 25 ps FWHM。
使用光学胶水将一个氟化铅切伦科夫辐射体贴到 MCP-PMT 的窗口面板上。
结果是，成功获得高于 50 ps FWHM 的 CTR，此结果与模拟结果一致 [刊文 3]。
集成切伦科夫辐射体的 MCP-PMT 的开发
上述切伦科夫探测器存在光学边界。光学边界会降低探测器的时序性能。我们开发了一种集成切伦科夫辐射体的 MCP-PMT (CRI-MCP-PMT)，以消除探测器的光学边界。将普通 MCP-PMT 的窗口面板更换为切伦科夫辐射体，并使用原子层沉积技术在辐射体和光阴极面之间插入氧化铝层。
使用一对 CRI-MCP-PMT 测量 CTR，获得的 CTR 为 41.9 ps FWHM [刊文 4]。此外，通过优化分析参数（例如定时拾取阈值电平和脉冲面积），将 CTR 提高至 30.1 ps FWHM。
使用无铅材料提高性能
通过从头开始回顾所有材料并应用 ALD 技术，我们成功创建了 ALD-MCP，可在不使用含铅材料的情况下确保低噪声和高信号倍增（增益率）。消除铅是向前迈出的一大步，因为在欧盟 (EU) 发布的 RoHS 指令中，铅作为有害物质而被限制使用。
一项符合实验表明，与普通 MCP-PMT 相比，集成 ALD-MCP 的 PMT 可将 CTR 从 41.9 提高到 35.4 ps FWHM [参考资料 6]。
无重建成像
我们利用上述探测器对以及独特的光探测和信号处理技术，成功地在世界上率先实现了无需图像重建的高精度正电子发射成像 [参考资料 7]。应用这些成功的研究结果有望实现一种完全创新的新型辐射医疗成像系统，该系统能够从简单、紧凑的设置中进行快速诊断，同时具有与当前使用的辐射成像系统（如正电子发射断层扫描 (PET)）相同或更高的精度。这将有助于提高检测病变组织或器官（如癌症）的检查效率，同时减少辐射照射剂量，减轻患者和医务人员的负担。我们将进一步提高探测器性能，使这一新概念更加实用。
出版物
1. R. Ota et al., Med. Phys. 45 (2018) pp. 1999-2008
2. F. Hashimoto et al.，Biomed. Phys. Eng. Express 5 (2019) 035001
3. R. Ota et al., Nucl. Inst. Meth. A 923 (2019) pp. 1-4
4. R. Ota et al.，Phys Med. Biol. 64 (2019) 07LT01
5. R. Ota et al., Phys. Med. biol. 65 (2020) 10NT03
6. R. Ota et al.，Phys Med. Biol. 66 (2021) 064006
专利
美国专利 10,795,035
美国专利 10,816,682
美国专利 10,996,348
美国专利 10,925,557
- Confirmation
-
It looks like you're in the . If this is not your location, please select the correct region or country below.
You're headed to Hamamatsu Photonics website for (Chinese). If you want to view an other country's site, the optimized information will be provided by selecting options below.
In order to use this website comfortably, we use cookies. For cookie details please see our cookie policy.
- Cookie Policy
-
This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in this cookie policy. By closing the cookie warning banner, scrolling the page, clicking a link or continuing to browse otherwise, you agree to the use of cookies.
Hamamatsu uses cookies in order to enhance your experience on our website and ensure that our website functions.
You can visit this page at any time to learn more about cookies, get the most up to date information on how we use cookies and manage your cookie settings. We will not use cookies for any purpose other than the ones stated, but please note that we reserve the right to update our cookies.
1. What are cookies?
For modern websites to work according to visitor’s expectations, they need to collect certain basic information about visitors. To do this, a site will create small text files which are placed on visitor’s devices (computer or mobile) - these files are known as cookies when you access a website. Cookies are used in order to make websites function and work efficiently. Cookies are uniquely assigned to each visitor and can only be read by a web server in the domain that issued the cookie to the visitor. Cookies cannot be used to run programs or deliver viruses to a visitor’s device.
Cookies do various jobs which make the visitor’s experience of the internet much smoother and more interactive. For instance, cookies are used to remember the visitor’s preferences on sites they visit often, to remember language preference and to help navigate between pages more efficiently. Much, though not all, of the data collected is anonymous, though some of it is designed to detect browsing patterns and approximate geographical location to improve the visitor experience.
Certain type of cookies may require the data subject’s consent before storing them on the computer.
2. What are the different types of cookies?
This website uses two types of cookies:
- First party cookies. For our website, the first party cookies are controlled and maintained by Hamamatsu. No other parties have access to these cookies.
- Third party cookies. These cookies are implemented by organizations outside Hamamatsu. We do not have access to the data in these cookies, but we use these cookies to improve the overall website experience.
3. How do we use cookies?
This website uses cookies for following purposes:
- Certain cookies are necessary for our website to function. These are strictly necessary cookies and are required to enable website access, support navigation or provide relevant content. These cookies direct you to the correct region or country, and support security and ecommerce. Strictly necessary cookies also enforce your privacy preferences. Without these strictly necessary cookies, much of our website will not function.
- Analytics cookies are used to track website usage. This data enables us to improve our website usability, performance and website administration. In our analytics cookies, we do not store any personal identifying information.
- Functionality cookies. These are used to recognize you when you return to our website. This enables us to personalize our content for you, greet you by name and remember your preferences (for example, your choice of language or region).
- These cookies record your visit to our website, the pages you have visited and the links you have followed. We will use this information to make our website and the advertising displayed on it more relevant to your interests. We may also share this information with third parties for this purpose.
Cookies help us help you. Through the use of cookies, we learn what is important to our visitors and we develop and enhance website content and functionality to support your experience. Much of our website can be accessed if cookies are disabled, however certain website functions may not work. And, we believe your current and future visits will be enhanced if cookies are enabled.
4. Which cookies do we use?
There are two ways to manage cookie preferences.
- You can set your cookie preferences on your device or in your browser.
- You can set your cookie preferences at the website level.
If you don’t want to receive cookies, you can modify your browser so that it notifies you when cookies are sent to it or you can refuse cookies altogether. You can also delete cookies that have already been set.
If you wish to restrict or block web browser cookies which are set on your device then you can do this through your browser settings; the Help function within your browser should tell you how. Alternatively, you may wish to visit www.aboutcookies.org, which contains comprehensive information on how to do this on a wide variety of desktop browsers.
5. What are Internet tags and how do we use them with cookies?
Occasionally, we may use internet tags (also known as action tags, single-pixel GIFs, clear GIFs, invisible GIFs and 1-by-1 GIFs) at this site and may deploy these tags/cookies through a third-party advertising partner or a web analytical service partner which may be located and store the respective information (including your IP-address) in a foreign country. These tags/cookies are placed on both online advertisements that bring users to this site and on different pages of this site. We use this technology to measure the visitors' responses to our sites and the effectiveness of our advertising campaigns (including how many times a page is opened and which information is consulted) as well as to evaluate your use of this website. The third-party partner or the web analytical service partner may be able to collect data about visitors to our and other sites because of these internet tags/cookies, may compose reports regarding the website’s activity for us and may provide further services which are related to the use of the website and the internet. They may provide such information to other parties if there is a legal requirement that they do so, or if they hire the other parties to process information on their behalf.
If you would like more information about web tags and cookies associated with on-line advertising or to opt-out of third-party collection of this information, please visit the Network Advertising Initiative website http://www.networkadvertising.org.
6. Analytics and Advertisement Cookies
We use third-party cookies (such as Google Analytics) to track visitors on our website, to get reports about how visitors use the website and to inform, optimize and serve ads based on someone's past visits to our website.
You may opt-out of Google Analytics cookies by the websites provided by Google:
https://tools.google.com/dlpage/gaoptout?hl=en
As provided in this Privacy Policy (Article 5), you can learn more about opt-out cookies by the website provided by Network Advertising Initiative:
http://www.networkadvertising.org
We inform you that in such case you will not be able to wholly use all functions of our website.
Close