Design and characterization of a hybrid PET detector with DOI capability

IF 3.2 2区医学 Q1 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Medical physics Pub Date : 2024-07-20 DOI:10.1002/mp.17313

Wen He, Yangyang Zhao, Honghao Zeng, Wenjie Huang, Hang Yang, Xin Zhao, Qiang Wang, Lu Wang, Ming Niu, Lei Zhang, Qiushi Ren, Zheng Gu

{"title":"Design and characterization of a hybrid PET detector with DOI capability","authors":"Wen He, Yangyang Zhao, Honghao Zeng, Wenjie Huang, Hang Yang, Xin Zhao, Qiang Wang, Lu Wang, Ming Niu, Lei Zhang, Qiushi Ren, Zheng Gu","doi":"10.1002/mp.17313","DOIUrl":null,"url":null,"abstract":"<div>\n \n \n <section>\n \n <h3> Background</h3>\n \n <p>Monolithic or semi-monolithic detectors are attractive for positron emission tomography (PET) scanners with depth-of-interaction (DOI) capability. However, they often require complicated calibrations to determine the interaction positions of gamma photons.</p>\n </section>\n \n <section>\n \n <h3> Purpose</h3>\n \n <p>We introduce a novel hybrid detector design that combines pixelated and semi-monolithic elements to achieve DOI capability while simplifying the calibrations for positioning.</p>\n </section>\n \n <section>\n \n <h3> Methods</h3>\n \n <p>A prototype detector with eight hybrid lutetium–yttrium oxyorthosilicate (LYSO) layers having dimensions of 25.8 × 12.9 × 15 mm<sup>3</sup> was constructed. The energy-weighted and energy-squared weighted averages were used for estimating the <i>x</i>- (pixelated direction) and <i>y</i>-positions (non-pixelated direction). Pseudo-pixels were defined as discrete areas on the flood image based on the crystal look-up table (LUT). The intrinsic spatial resolutions in the pixelated and non-pixelated directions were measured. The ratio of the maximum to the sum of the multipixel photon counter (MPPC) signals was used to estimate the DOI positions. The coincidence timing resolution (CTR) was measured using the average and energy-weighted average of the earliest <i>n</i> time stamps. Two energy windows of 250–700 and 400–600 keV were applied for the measurements.</p>\n </section>\n \n <section>\n \n <h3> Results</h3>\n \n <p>The pattern of the flood images showed discrete event clusters, demonstrating that simple calibrations for determining the <i>x-</i> and <i>y</i>-positions of events could be achieved. Under 400–600 keV energy window, the average intrinsic spatial resolutions were 1.15 and 1.34 mm for the pixelated and non-pixelated directions; the average DOI resolution of the second row of pseudo-pixels was 5.1 mm in full width at half maximum (FWHM); when using the energy-weighted average of the earliest four-time stamps, the best CTR of 350 ps was achieved. Applying a broader energy window of 250–700 keV only slightly degrades the DOI resolution while maintaining the intrinsic resolution; the best CTR degrades to 410 ps.</p>\n </section>\n \n <section>\n \n <h3> Conclusions</h3>\n \n <p>The proposed hybrid detector concept was verified, and a prototype detector showed high performance for 3D positioning and timing resolution. The novel detector concept shows promise for preclinical and clinical PET scanners with DOI capability.</p>\n </section>\n </div>","PeriodicalId":18384,"journal":{"name":"Medical physics","volume":"51 10","pages":"7140-7152"},"PeriodicalIF":3.2000,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Medical physics","FirstCategoryId":"3","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/mp.17313","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING","Score":null,"Total":0}

引用次数: 0

Abstract

Background

Monolithic or semi-monolithic detectors are attractive for positron emission tomography (PET) scanners with depth-of-interaction (DOI) capability. However, they often require complicated calibrations to determine the interaction positions of gamma photons.

Purpose

We introduce a novel hybrid detector design that combines pixelated and semi-monolithic elements to achieve DOI capability while simplifying the calibrations for positioning.

Methods

A prototype detector with eight hybrid lutetium–yttrium oxyorthosilicate (LYSO) layers having dimensions of 25.8 × 12.9 × 15 mm³ was constructed. The energy-weighted and energy-squared weighted averages were used for estimating the x- (pixelated direction) and y-positions (non-pixelated direction). Pseudo-pixels were defined as discrete areas on the flood image based on the crystal look-up table (LUT). The intrinsic spatial resolutions in the pixelated and non-pixelated directions were measured. The ratio of the maximum to the sum of the multipixel photon counter (MPPC) signals was used to estimate the DOI positions. The coincidence timing resolution (CTR) was measured using the average and energy-weighted average of the earliest n time stamps. Two energy windows of 250–700 and 400–600 keV were applied for the measurements.

Results

The pattern of the flood images showed discrete event clusters, demonstrating that simple calibrations for determining the x- and y-positions of events could be achieved. Under 400–600 keV energy window, the average intrinsic spatial resolutions were 1.15 and 1.34 mm for the pixelated and non-pixelated directions; the average DOI resolution of the second row of pseudo-pixels was 5.1 mm in full width at half maximum (FWHM); when using the energy-weighted average of the earliest four-time stamps, the best CTR of 350 ps was achieved. Applying a broader energy window of 250–700 keV only slightly degrades the DOI resolution while maintaining the intrinsic resolution; the best CTR degrades to 410 ps.

Conclusions

The proposed hybrid detector concept was verified, and a prototype detector showed high performance for 3D positioning and timing resolution. The novel detector concept shows promise for preclinical and clinical PET scanners with DOI capability.

查看原文本刊更多论文

具有 DOI 功能的混合 PET 探测器的设计与表征。

背景：单片或半单片探测器对于具有相互作用深度（DOI）功能的正电子发射断层扫描（PET）扫描仪很有吸引力。目的：我们介绍了一种新型混合探测器设计，它结合了像素化和半单片元件，在实现 DOI 功能的同时简化了定位校准：方法：我们建造了一个具有八个混合镥-钇氧正硅酸盐（LYSO）层的探测器原型，其尺寸为 25.8 × 12.9 × 15 mm3。能量加权和能量平方加权平均值用于估算 x 位置（像素化方向）和 y 位置（非像素化方向）。根据晶体查找表（LUT），将伪像素定义为洪水图像上的离散区域。测量了像素化方向和非像素化方向的固有空间分辨率。多像素光子计数器（MPPC）信号的最大值与总和之比用于估算 DOI 位置。使用最早 n 个时间戳的平均值和能量加权平均值测量重合时间分辨率（CTR）。测量采用了 250-700 和 400-600 千伏的两个能量窗口：洪水图像的模式显示出离散的事件群，这表明可以通过简单的校准来确定事件的 x 和 y 位置。在 400-600 keV 能量窗口下，像素方向和非像素方向的平均固有空间分辨率分别为 1.15 和 1.34 毫米；第二排伪像素的平均 DOI 分辨率为 5.1 毫米（全宽半最大值）；使用最早四个时间戳的能量加权平均值时，最佳 CTR 为 350 ps。采用 250-700 keV 的更宽能量窗口只会轻微降低 DOI 分辨率，同时保持固有分辨率；最佳 CTR 降至 410 ps：提出的混合探测器概念得到了验证，探测器原型在三维定位和定时分辨率方面表现出了很高的性能。新颖的探测器概念为具有 DOI 功能的临床前和临床 PET 扫描仪带来了希望。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Medical physics 医学-核医学

CiteScore

6.80

自引率

15.80%

发文量

660

审稿时长

1.7 months

期刊介绍： Medical Physics publishes original, high impact physics, imaging science, and engineering research that advances patient diagnosis and therapy through contributions in 1) Basic science developments with high potential for clinical translation 2) Clinical applications of cutting edge engineering and physics innovations 3) Broadly applicable and innovative clinical physics developments Medical Physics is a journal of global scope and reach. By publishing in Medical Physics your research will reach an international, multidisciplinary audience including practicing medical physicists as well as physics- and engineering based translational scientists. We work closely with authors of promising articles to improve their quality.