18F-FDG符合线路显像与67Ga显像诊断结节病的对比研究

目的 对比分析^18F-脱氧葡萄糖(FDG)符合线路显像(FDG显像)和^67Ga显像对结节病的诊断和疗效监测的价值。方法 17例结节病患者行^18F-FDG显像，其中11例行^67Ga显像。以目测法判断纵隔和肺门淋巴结放射性摄取程度，明显超过周围肺组织本底水平者为阳性。结果 11例未治疗的结节病患者^18F-FDG显像均阳性，其中7例行^67Ga显像者影像特征与^18F-FDG显像相似；^18F-FDG、^67Ga显像均阳性的2例患者，治疗后X线片示病灶吸收，再次显像均为阴性；^18F-FDG显像本底较低且显像效果较好。3例已治疗者X线片示病灶吸收，^18F—FDG显像均阴性，其中2例行^67Ga显像也阴性。3例临床诊断为结节病者，^18F-FDG显像阳性，其中2例^67Ga显像也阳性(1例治疗后2种显像仍呈阳性，而X线片示纵隔肺门肿大淋巴结缩小)。结论 ^18F-FDG符合线路显像比^67Ga显像效果好,对结节病诊断和治疗效果监测有较好的应用价值。     

18F-FDG PET显像用于鼻咽癌诊断及分期

目的 探讨^18F-脱氧葡萄糖（FDG）PET显像在鼻咽癌诊断中的价值。方法 回顾性分析33例鼻咽癌患者的^18F-FDG PET显像效果。其中初诊患者4例，治疗后29例。行常规头颈部或全身^18F-FDG PET显像。结果 ①33例患者中，鼻咽部有恶性病灶（原发或复发病灶）者16例，PET灵敏度为100％，假阳性2例，特异性为88．3％，准确性为93．9％。与PET显像前的21例CT或MRI结果相比较，PET3检出鼻咽部恶性病灶10例，较CT或MRI多检出2例。②33例中22例有转移灶，PET检出20例（90．9％），较PET显像前的其他检查多检出5例；PET显像和PET显像前的其他检查皆有3例假阳性。在检出转移病灶数方面，PET显像多发现1处或多处转移灶有13例，PET显像少发现转移灶的2例。结论 ^18F-FDG PET显像灵敏、准确、全面，在鼻咽癌的诊断、早期复发灶及全身转移灶检出方面有重要价值。     

^18F-FDG PET在淋巴瘤分期和治疗反应评价中的价值

^18F-FDG PET显像对淋巴瘤的诊断、分期作用显著，对淋巴瘤病灶的探测灵敏度和准确性高于67Ga显像。在化疗过程中和化疗后持续^18F-FDG PET阳性对预测复发有高灵敏度。治疗结束时^18F-FDG PET阴性提示患者预后好。与其他常规显像相比，^18F-FDG PET在监测淋巴瘤疗效、判断治疗反应方面有独特优势。     

18F-FDG符合线路显像在恶性淋巴瘤诊断及疗效判断中的应用

目的 探讨^18F-脱氧葡萄糖(FDG)双探头符合线路显像在淋巴瘤诊断及疗效判断中的应用。方法 对病理检查证实的56例恶性淋巴瘤患者行^18F-FDG显像，并与同期CT、MRI或B超等影像检查结果(CI)进行对比分析。56例患者中治疗前9例，化疗中21例，放化疗后10例，术后复查16例。结果 ①9例治疗前患者中7例^18F-FDG显像阳性，8例CI检查阳性。^18F-FDG显像与CI显示的病灶部位基本一致。②21例化疗患者中12例^18F-FDG显像阳性，15例CI阳性，有3例患者CT示有肿大淋巴结，但FDG摄取未见异常。③对16例淋巴瘤术后患者行^18F-FDG显像寻找术后残余病灶，发现3例FDG异常摄取。④10例放化疗后患者中4例FDG摄取异常(纵隔2例，骨2例)。⑤对7例同期行^18F-FDG显像与骨显像的患者进行分析，发现两者所示骨病灶部位不尽一致。结论 ^18F-FDG显像是恶性淋巴瘤诊断、分期及疗效观察的重要手段之一，可及时发现手术后肿瘤残余、复发。^18F-FDG显像与骨显像相互补充，可提高诊断恶性淋巴瘤骨髓浸润的灵敏度。CT同机图像融合技术能帮助定位肿瘤。     

18F-FDG PET/CT显像在原发性乳腺肿瘤鉴别诊断中的应用

目的探讨^18F-脱氧葡萄糖(FDG)PET／CT显像鉴别诊断乳房肿块良恶性的临床价值。方法乳房肿块患者34例，按体重5．55MBq/kg静脉注射^18F-FDG后40min行胸部俯卧位PET／CT显像，必要时加做3h延迟显像。经衰减校正后以半定量分析法[测定病灶的标准摄取值(SUV)及靶组织/非靶组织比值(T/NT)]及目测法进行图像分析，并与病理检查结果对照。结果手术病理检查证实乳腺癌27例，良性病变7例。^18F-FDG PET／CT显像目测法对乳房肿块良恶性鉴别的灵敏度为92．59％，特异性为6／7例，阳性预测值为96．15％。结论^F-FDG PET／CT显像是目前鉴别诊断乳房肿块性质较好的无创性检查方法。     

淋巴瘤骨髓浸润的18F-FDG PET显像研究

目的 用^18F-脱氧葡萄糖（FDG）PET显像研究淋巴瘤细胞骨髓浸润。方法 恶性淋巴癌患者30例，其中非霍奇金淋巴瘤（NHL）20例、霍奇金病（HD）10例，进行全身^18F-FDG PET显像。局灶性边缘清楚的淋巴结相应区域^18F-FDG浓聚视为恶性淋巴结显影。利用灰度色标，视觉分析骨髓及肝脏内^18F-FDG浓聚情况。骨髓的^18F-FDG分布不均，摄取高于肝脏，判断为骨髓^18F-FDG摄取异常；骨髓的^18F-FDG分布均匀，摄取低于或等于肝脏，判断为骨髓^18F-FDG摄取正常。所有患者均行髂棘的骨髓活组织检查。结果 30例中18例有淋巴结摄取^18F-FDG；12例淋巴结摄取^18F-FDG阴性患者中，8例NHL，4例HD。有26例患者的骨髓^18F-FDG摄取情况与骨髓组织学检查结果一致，其中骨髓有淋巴细胞浸润7例，无淋巴细胞浸润19例。有3例骨髓组织学检查阴性的患者，^18F-FDG PET示骨髓^18F-FDG摄取异常、骨髓有淋巴细胞浸润；1例NHL患者，骨髓组织学检查阳性但^18F-FDG PET示骨髓^18F-FDG摄取正常。结论 ^18F-DG PET全身显像能正确评价骨髓淋巴细胞浸润情况，减少对淋巴瘤分期所进行的骨髓组织学检查。     

18F-FDG符合线路显像在头颈部恶性肿瘤诊断中的应用

目的评价^18F-脱氧葡萄糖(FDG)符合线路显像(DHTE)诊断头颈部恶性肿瘤的应用价值。方法头颈部恶性肿瘤患者55例，其中鼻咽癌34例(初发12例，放疗后22例)、其他头颈部癌术后13例和原因不明的颈部转移瘤8例，进行^18F-FDG DHTC。结果①^18F-FDG DHTC诊断原发头颈部恶性病灶的灵敏度、特异性和准确性分别为90．5％(19／21例)，80．8％(21／26例)和85．1％(40／47例)；诊断转移瘤的灵敏度和特异性分别为93．8％(30／32例)和86．7％(13／15例)。②8例淋巴结转移瘤患者中，4例颈外见异常单个^18F-FDG浓聚灶，为原发病灶；1例显像阴性；3例见多发性^18F-FDG异常浓聚，未能定位原发病灶。结论^18F-FDG DHTC诊断原发头颈部恶性病灶和寻找颈部转移瘤的原发灶有较大的临床价值。     

^18F—FDG PET显像与^99Tc^m—MDP全身骨显像诊断肿瘤远处转移的比较

目的 评价^18F-脱氧葡萄糖（FDG）PET肿瘤显像与^99Tc^m-亚甲基二膦酸盐（MDP）全身骨显像对检出骨和远处转移的价值。方法 对16例恶性肿瘤放化疗后的患者进行^18F-FDG PET显像和^99Tc^m-MDP全身骨显像，并对两种结果进行了比较。结果 16例肿瘤患者中^18F-FDG PET显像皆阳性，其中14例患者有远处转移，转移病灶共62处，其中骨转移病灶20处；在全身骨显像中，11例有局限性异常放射性浓聚，其中2例为单一病灶，9例为多发病灶，共检出病灶57处，另5例骨显像正常。结论 ^18F-FDG PET对恶性肿瘤的诊断具有较高的准确性和特异性，但对骨转移灶的诊断价值相对较差；^99Tc^m-MDP显像阴性或单一病灶的可疑转移瘤患者有必要进行^18F－FDG PET检查，以明确诊断其他远处转移灶。     

18F-FDG PET显像在胃癌术后复发及转移中的应用

目的探讨^18F-脱氧葡萄糖(FDG)PET显像诊断胃癌术后复发及转移的价值。方法41例临床疑胃癌术后复发患者行^18F-FDG PET全身显像。图像分析采用视觉及半定量方法(标准摄取值，SUV)，并参考近期病理检查、CT或核素骨显像结果：结果①21例复发患者(经组织病理学、CT、核素骨显像及临床随访证实)，PET检出胃癌术后复发及转移的灵敏度为90．5％，特异性80．0％，阳性预测值、阴性预测值和准确性分别为82．6％、88．9％和85．4％。②21例术后复发及转移患者中，PET与CT均阳性13例共16例次，PET平均每例次检出病灶数多于CT。③12例术后复发及转移患者化疗后共进行15次PET复查。5例化疗后PET显像示病情好转，随访17～36个月均存活，7例化疗后PET显像示化疗效果欠佳．存活时间为6～10个月。结论^18F-FDG PET显像是诊断胃癌术后复发及转移的有用方法，并对监测胃癌术后复发的化疗效果有重要意义。     

18F-FDG和18F-FET PET脑显像诊断垂体腺瘤

目的 比较^18F-脱氧葡萄糖(FDG)和^18F-酪氨酸(FET)PET显像对垂体腺瘤的诊断价值。方法 正常对照者7例同期行^18F-FDGPET脑显像和^13N-NH3PET脑血流显像。20例垂体腺瘤患者行^18F-FDG PET脑显像，其中10例同期行^18F-FETPET脑显像，并参照近期MRI结果进行分析。加例患者均行经口鼻蝶窦垂体腺瘤切除术，术后行病理检查及免疫组织化学分型。结果①正常对照组垂体^18F-FDG摄取明显低于周围组织。②对于分泌激素和无分泌功能的垂体腺瘤，^18F-FDGPET和^18F-FETPET均可显示病灶。③垂体腺瘤在^18F-FDG显像中多表现为均匀的放射性摄取增高，而^18F-FET。显像则多表现为散在的摄取增高，与MRI所示等瓦长T2或稍长瓦长T2信号的肿瘤组织分布相似。④7例微腺瘤^18F-FDG PET检出5例，MRI检出3例。⑤不同激素分泌型和无分泌功能垂体腺瘤的瘤体大小、激素水平与^18F-FDG或^18F-FET显像标准摄取值(SUV)间无明显相关。结论 ^18F-FDG和^18F-FET PET脑显像均可显示垂体腺瘤,而以前者更佳。     

发作间期PET显像与发作期SPECT显像在癫痫灶定位中的应用

目的：探讨发作间期PET显像与发作期SPECT显像在癫痫灶定位中的特点和相关性。方法：对54例癫痫患者行发作间期PET和发作期SPECT2次检查,对结果进行对比分析。结果：54例发作间期PET显像示低代谢者中33例（61．1％）表现为单叶局限性低代谢,21例（38．9％）表现为多个病灶或弥漫性改变。发作期SPECT显像50例可见高灌注灶,高灌注中37例（74％）为单叶局限性高灌注,13例（26％）为多个病灶,未见弥漫性高灌注。2项检查比较,46例（85．2％）2项检查结果相符合,其中32例（69．6％）显示为颞叶病灶。发作间期PET示多病灶及弥漫性改变者于发作期SPECT为像时为9例（42．9％）转化为单叶局限性病灶,7例（33．3％）排除了部分低代谢病灶。结论：癫痫灶灌注与代谢改变具有明显的相关性。发作间期PET显像定位癫痫灶解剖结构显示较为清晰,发作期SPECT显像替代发作期PET检查可提高定位特异。2项检查联合应用可排除非致痫性病变和发作过程中痫性电活动的泛化,具有较好的互补性。     

符合线路显像与PET显像中SUV的比较研究

目的比较符合线路显像标准摄取值(SUV)与PET显像的SUV。方法用双探头符合显像仪及PET对模型显像，分别采用不同的重建算法重建，测定图像上热灶的SUV。结果对直径小于30mm热灶，相同大小时，PET、得到的SUV高于符合线路显像；无论对PET还是符合线路显像，随热灶大小增加SUV增加；SUV与重建算法有关；选取的感兴趣区(ROI)越大，获得的SUV越小；由PET图像获得的热灶SUV可见，当热灶大于2倍的系统分辨率时，SUCmax接近热灶的真实值(SUVmax)。结论符合线路显像的SUV低于PET显像；病灶大小、重建算法、ROI大小均影响SUV。     

核医学技术在肿瘤治疗中的应用与进展

核医学功能代谢显像与放射性粒子种植治疗是目前肿瘤治疗研究的前沿问题之一,为肿瘤治疗提供了有力的武器。核医学功能代谢显像较CT能更早地显示肿瘤部位和扩散范围,对肿瘤临床分期、制定手术和放射治疗计划具有重要意义,是常规CT和MRI的有益补充。放射性粒子植入治疗安全且疗效肯定,是肿瘤综合治疗的手段之一。     

核医学影像在肌萎缩侧索硬化临床研究中的应用

肌萎缩侧索硬化（ALS）起病隐匿、进展迅速、诊断困难,其神经影像学改变目前尚缺乏明确特异性指征。SPECT和PET是最早应用于ALS的神经影像学技术。像素分析软件的运用（如SPM等）使SPECT、PET对ALS的研究更加方便和客观。近年来,脑受体PET显像不断发展,逐渐显示出其在ALS早期诊断及认知功能受损研究中的重要价值。     

双探头符合线路SPECT正电子显像衰减校正实验研究

Objective The photons from the body would be attenuated in their intensity by the soft tissue before they reach the detectors. Some of them lost more intensity than others when coming from the deeper body. Attenuation of the photons would distort the image, affect the image quality, and may lead to misdiagnosis. In this research the X-ray and γ-ray were used as transmission resources for accurate assess-ment of attenuation in each part of the body. The transmission data was used to correct the emission data from the body. Iteration algorithm was used for the reconstruction of attenuation corrected tomography ima-ges. Evaluate the efficacy of attenuation correction in duel head hybrid SPECT/coincidence PET systems (SPECT/PET) and SPECT using both the Jaszczak and the myocardial phantoms. Methods For PET phantom study, the Jaszczak phantom was filled with the aqueous solution of 18F-fluorodeoxyglucose (FDG) and was scanned with two hybrid SPECT/coincidence PET systems respectively (Vertex Plus, Netherlands Philips ADAC Company and Hawkeye, USA GE Company). The PET images were acquired and reconstruc-ted. Results The "cold" lesion, which the diameter was less than 12 mm of uncorrected image, could not be identified. But it, after correction, diameter 9 mm, would be recognized clearly, less than 7 mm would not be distinguished. Noncorrected image could only identify "hot" lesions which the diameter were 9, 12, 14, 18, 22 and 38 mm, while in the corrected image, not only it was much better, but also the "hot" le-sion of 6 mm was distinguished. In Hawkeye, the same situation, the corrected image of was improved obvi-ously; the disparity of counts between surrounding and deep center less, and the counts in deep center were compensated. There were only 3 round " cold" lesions could be recognized, the diameter: 14, 18 and 20 mm; all of them which diameter were less than 12 mm could not be distinguished. One in the center was al-most as background, and could not be identified. The radioactive accounts of surrounding and center were quite different. The corrected image 5 "cold" lesions could be found, 9, 12, 14, 18 and 20 mm, but7 mm could not be found. The noncorrected image, only 12, 14, 18, 22 and 38 mm " hot" lesions could be found, and by the surrounding, there was an arc shape "hot" lesion. But it could distinguish 9, 12, 14, 18, 22 and 38 mm "hot" lesions on the corrected image, and the image was much better than noncorrected one. Conclusions The corrected image of Vertex Plus was improved obviously with the disparity of counts between surrounding and deep center less, and the counts in deep center was compensated. The result of at-tenuation with phantom showed that 137Cs was better than CT in both image quality and spatial resolution.     

双探头符合线路SPECT正电子显像衰减校正实验研究

Objective The photons from the body would be attenuated in their intensity by the soft tissue before they reach the detectors. Some of them lost more intensity than others when coming from the deeper body. Attenuation of the photons would distort the image, affect the image quality, and may lead to misdiagnosis. In this research the X-ray and γ-ray were used as transmission resources for accurate assess-ment of attenuation in each part of the body. The transmission data was used to correct the emission data from the body. Iteration algorithm was used for the reconstruction of attenuation corrected tomography ima-ges. Evaluate the efficacy of attenuation correction in duel head hybrid SPECT/coincidence PET systems (SPECT/PET) and SPECT using both the Jaszczak and the myocardial phantoms. Methods For PET phantom study, the Jaszczak phantom was filled with the aqueous solution of 18F-fluorodeoxyglucose (FDG) and was scanned with two hybrid SPECT/coincidence PET systems respectively (Vertex Plus, Netherlands Philips ADAC Company and Hawkeye, USA GE Company). The PET images were acquired and reconstruc-ted. Results The "cold" lesion, which the diameter was less than 12 mm of uncorrected image, could not be identified. But it, after correction, diameter 9 mm, would be recognized clearly, less than 7 mm would not be distinguished. Noncorrected image could only identify "hot" lesions which the diameter were 9, 12, 14, 18, 22 and 38 mm, while in the corrected image, not only it was much better, but also the "hot" le-sion of 6 mm was distinguished. In Hawkeye, the same situation, the corrected image of was improved obvi-ously; the disparity of counts between surrounding and deep center less, and the counts in deep center were compensated. There were only 3 round " cold" lesions could be recognized, the diameter: 14, 18 and 20 mm; all of them which diameter were less than 12 mm could not be distinguished. One in the center was al-most as background, and could not be identified. The radioactive accounts of surrounding and center were quite different. The corrected image 5 "cold" lesions could be found, 9, 12, 14, 18 and 20 mm, but7 mm could not be found. The noncorrected image, only 12, 14, 18, 22 and 38 mm " hot" lesions could be found, and by the surrounding, there was an arc shape "hot" lesion. But it could distinguish 9, 12, 14, 18, 22 and 38 mm "hot" lesions on the corrected image, and the image was much better than noncorrected one. Conclusions The corrected image of Vertex Plus was improved obviously with the disparity of counts between surrounding and deep center less, and the counts in deep center was compensated. The result of at-tenuation with phantom showed that 137Cs was better than CT in both image quality and spatial resolution.     

双探头符合线路SPECT正电子显像衰减校正实验研究

Objective The photons from the body would be attenuated in their intensity by the soft tissue before they reach the detectors. Some of them lost more intensity than others when coming from the deeper body. Attenuation of the photons would distort the image, affect the image quality, and may lead to misdiagnosis. In this research the X-ray and γ-ray were used as transmission resources for accurate assess-ment of attenuation in each part of the body. The transmission data was used to correct the emission data from the body. Iteration algorithm was used for the reconstruction of attenuation corrected tomography ima-ges. Evaluate the efficacy of attenuation correction in duel head hybrid SPECT/coincidence PET systems (SPECT/PET) and SPECT using both the Jaszczak and the myocardial phantoms. Methods For PET phantom study, the Jaszczak phantom was filled with the aqueous solution of 18F-fluorodeoxyglucose (FDG) and was scanned with two hybrid SPECT/coincidence PET systems respectively (Vertex Plus, Netherlands Philips ADAC Company and Hawkeye, USA GE Company). The PET images were acquired and reconstruc-ted. Results The "cold" lesion, which the diameter was less than 12 mm of uncorrected image, could not be identified. But it, after correction, diameter 9 mm, would be recognized clearly, less than 7 mm would not be distinguished. Noncorrected image could only identify "hot" lesions which the diameter were 9, 12, 14, 18, 22 and 38 mm, while in the corrected image, not only it was much better, but also the "hot" le-sion of 6 mm was distinguished. In Hawkeye, the same situation, the corrected image of was improved obvi-ously; the disparity of counts between surrounding and deep center less, and the counts in deep center were compensated. There were only 3 round " cold" lesions could be recognized, the diameter: 14, 18 and 20 mm; all of them which diameter were less than 12 mm could not be distinguished. One in the center was al-most as background, and could not be identified. The radioactive accounts of surrounding and center were quite different. The corrected image 5 "cold" lesions could be found, 9, 12, 14, 18 and 20 mm, but7 mm could not be found. The noncorrected image, only 12, 14, 18, 22 and 38 mm " hot" lesions could be found, and by the surrounding, there was an arc shape "hot" lesion. But it could distinguish 9, 12, 14, 18, 22 and 38 mm "hot" lesions on the corrected image, and the image was much better than noncorrected one. Conclusions The corrected image of Vertex Plus was improved obviously with the disparity of counts between surrounding and deep center less, and the counts in deep center was compensated. The result of at-tenuation with phantom showed that 137Cs was better than CT in both image quality and spatial resolution.     

双探头符合线路SPECT正电子显像衰减校正实验研究

Objective The photons from the body would be attenuated in their intensity by the soft tissue before they reach the detectors. Some of them lost more intensity than others when coming from the deeper body. Attenuation of the photons would distort the image, affect the image quality, and may lead to misdiagnosis. In this research the X-ray and γ-ray were used as transmission resources for accurate assess-ment of attenuation in each part of the body. The transmission data was used to correct the emission data from the body. Iteration algorithm was used for the reconstruction of attenuation corrected tomography ima-ges. Evaluate the efficacy of attenuation correction in duel head hybrid SPECT/coincidence PET systems (SPECT/PET) and SPECT using both the Jaszczak and the myocardial phantoms. Methods For PET phantom study, the Jaszczak phantom was filled with the aqueous solution of 18F-fluorodeoxyglucose (FDG) and was scanned with two hybrid SPECT/coincidence PET systems respectively (Vertex Plus, Netherlands Philips ADAC Company and Hawkeye, USA GE Company). The PET images were acquired and reconstruc-ted. Results The "cold" lesion, which the diameter was less than 12 mm of uncorrected image, could not be identified. But it, after correction, diameter 9 mm, would be recognized clearly, less than 7 mm would not be distinguished. Noncorrected image could only identify "hot" lesions which the diameter were 9, 12, 14, 18, 22 and 38 mm, while in the corrected image, not only it was much better, but also the "hot" le-sion of 6 mm was distinguished. In Hawkeye, the same situation, the corrected image of was improved obvi-ously; the disparity of counts between surrounding and deep center less, and the counts in deep center were compensated. There were only 3 round " cold" lesions could be recognized, the diameter: 14, 18 and 20 mm; all of them which diameter were less than 12 mm could not be distinguished. One in the center was al-most as background, and could not be identified. The radioactive accounts of surrounding and center were quite different. The corrected image 5 "cold" lesions could be found, 9, 12, 14, 18 and 20 mm, but7 mm could not be found. The noncorrected image, only 12, 14, 18, 22 and 38 mm " hot" lesions could be found, and by the surrounding, there was an arc shape "hot" lesion. But it could distinguish 9, 12, 14, 18, 22 and 38 mm "hot" lesions on the corrected image, and the image was much better than noncorrected one. Conclusions The corrected image of Vertex Plus was improved obviously with the disparity of counts between surrounding and deep center less, and the counts in deep center was compensated. The result of at-tenuation with phantom showed that 137Cs was better than CT in both image quality and spatial resolution.     

双探头符合线路SPECT正电子显像衰减校正实验研究

Objective The photons from the body would be attenuated in their intensity by the soft tissue before they reach the detectors. Some of them lost more intensity than others when coming from the deeper body. Attenuation of the photons would distort the image, affect the image quality, and may lead to misdiagnosis. In this research the X-ray and γ-ray were used as transmission resources for accurate assess-ment of attenuation in each part of the body. The transmission data was used to correct the emission data from the body. Iteration algorithm was used for the reconstruction of attenuation corrected tomography ima-ges. Evaluate the efficacy of attenuation correction in duel head hybrid SPECT/coincidence PET systems (SPECT/PET) and SPECT using both the Jaszczak and the myocardial phantoms. Methods For PET phantom study, the Jaszczak phantom was filled with the aqueous solution of 18F-fluorodeoxyglucose (FDG) and was scanned with two hybrid SPECT/coincidence PET systems respectively (Vertex Plus, Netherlands Philips ADAC Company and Hawkeye, USA GE Company). The PET images were acquired and reconstruc-ted. Results The "cold" lesion, which the diameter was less than 12 mm of uncorrected image, could not be identified. But it, after correction, diameter 9 mm, would be recognized clearly, less than 7 mm would not be distinguished. Noncorrected image could only identify "hot" lesions which the diameter were 9, 12, 14, 18, 22 and 38 mm, while in the corrected image, not only it was much better, but also the "hot" le-sion of 6 mm was distinguished. In Hawkeye, the same situation, the corrected image of was improved obvi-ously; the disparity of counts between surrounding and deep center less, and the counts in deep center were compensated. There were only 3 round " cold" lesions could be recognized, the diameter: 14, 18 and 20 mm; all of them which diameter were less than 12 mm could not be distinguished. One in the center was al-most as background, and could not be identified. The radioactive accounts of surrounding and center were quite different. The corrected image 5 "cold" lesions could be found, 9, 12, 14, 18 and 20 mm, but7 mm could not be found. The noncorrected image, only 12, 14, 18, 22 and 38 mm " hot" lesions could be found, and by the surrounding, there was an arc shape "hot" lesion. But it could distinguish 9, 12, 14, 18, 22 and 38 mm "hot" lesions on the corrected image, and the image was much better than noncorrected one. Conclusions The corrected image of Vertex Plus was improved obviously with the disparity of counts between surrounding and deep center less, and the counts in deep center was compensated. The result of at-tenuation with phantom showed that 137Cs was better than CT in both image quality and spatial resolution.     

双探头符合线路SPECT正电子显像衰减校正实验研究

Objective The photons from the body would be attenuated in their intensity by the soft tissue before they reach the detectors. Some of them lost more intensity than others when coming from the deeper body. Attenuation of the photons would distort the image, affect the image quality, and may lead to misdiagnosis. In this research the X-ray and γ-ray were used as transmission resources for accurate assess-ment of attenuation in each part of the body. The transmission data was used to correct the emission data from the body. Iteration algorithm was used for the reconstruction of attenuation corrected tomography ima-ges. Evaluate the efficacy of attenuation correction in duel head hybrid SPECT/coincidence PET systems (SPECT/PET) and SPECT using both the Jaszczak and the myocardial phantoms. Methods For PET phantom study, the Jaszczak phantom was filled with the aqueous solution of 18F-fluorodeoxyglucose (FDG) and was scanned with two hybrid SPECT/coincidence PET systems respectively (Vertex Plus, Netherlands Philips ADAC Company and Hawkeye, USA GE Company). The PET images were acquired and reconstruc-ted. Results The "cold" lesion, which the diameter was less than 12 mm of uncorrected image, could not be identified. But it, after correction, diameter 9 mm, would be recognized clearly, less than 7 mm would not be distinguished. Noncorrected image could only identify "hot" lesions which the diameter were 9, 12, 14, 18, 22 and 38 mm, while in the corrected image, not only it was much better, but also the "hot" le-sion of 6 mm was distinguished. In Hawkeye, the same situation, the corrected image of was improved obvi-ously; the disparity of counts between surrounding and deep center less, and the counts in deep center were compensated. There were only 3 round " cold" lesions could be recognized, the diameter: 14, 18 and 20 mm; all of them which diameter were less than 12 mm could not be distinguished. One in the center was al-most as background, and could not be identified. The radioactive accounts of surrounding and center were quite different. The corrected image 5 "cold" lesions could be found, 9, 12, 14, 18 and 20 mm, but7 mm could not be found. The noncorrected image, only 12, 14, 18, 22 and 38 mm " hot" lesions could be found, and by the surrounding, there was an arc shape "hot" lesion. But it could distinguish 9, 12, 14, 18, 22 and 38 mm "hot" lesions on the corrected image, and the image was much better than noncorrected one. Conclusions The corrected image of Vertex Plus was improved obviously with the disparity of counts between surrounding and deep center less, and the counts in deep center was compensated. The result of at-tenuation with phantom showed that 137Cs was better than CT in both image quality and spatial resolution.