正电子发射型计算机断层显像在肿瘤临床中的应用

正电子发射型计算机断层显像 (positronemissiontomography ,PET)是核医学最高水平的标志。PET技术是惟一的用解剖形态方式进行功能、代谢和受体显像的技术 ,可显示生物物质相应活动的空间分布、数量及其随时间的变化 ,故又称为生化显像或分子显像。其常用显像剂为带正电子的放射性核素 ,如 11C、13N、15O、18F等。以FDG(Fluorodeo xyglucose)为示踪剂的PET影像已广泛应用于肿瘤临床 ,使肿瘤的诊断、分期和治疗方案的选择发生了根本性变革。可以预期 ,由于PET的应用 ,将对临床产生深远的影响 :(1)从单纯以解剖学为基础的图像技术所…     

肿瘤乏氧的正电子发射断层显像及其临床应用

乏氧是恶性肿瘤内普遍存在的现象，是肿瘤侵袭性以及对放化疗抗拒的重要原因之一。应用正电子发射断层显像（PET），可以全面、无创和重复地检测肿瘤乏氧。并可用来预测肿瘤预后、评价疗效及指导临床治疗。     

肿瘤乏氧的正电子发射断层显像及其临床应用

乏氧是恶性肿瘤内普遍存在的现象,是肿瘤侵袭性以及对放化疗抗拒的重要原因之一。应用正电子发射断层显像(PET),可以全面、无创和重复地检测肿瘤乏氧,并可用来预测肿瘤预后、评价疗效及指导临床治疗。     

正电子发射型计算机断层显像对肺部结节合并多病灶的诊疗意义

背景与目的：近年，正电子发射型计算机断层显像检查（positron emission tomography，PET）逐渐在许多城市中兴起，为肿瘤的良恶性鉴别提供了有力的依据，PET对肺孤立性结节的诊断已有较多的研究。本研究回顾分析20例肺部肿瘤合并多病灶的病例来探讨PET在肺部结节合并多病灶的诊断中的意义。方法：收集上海胸科医院2004年8月-2005年6月住院病例20例，术前行18-FDG-PET检查及X线、CT（computerized tomography）、骨SPECT（single photonemisson computed tomography）扫描检查，疑有脊扯转移者行MRI（magnetic reimage）检查。其中14例获手术病理。结果：肺部原发灶的PET诊断符合率为100％，除原发灶以外病灶：PET阳性者6例，其中2例为肺部结节，其结节直径均大于1cm，3例为纵隔淋巴结，1例为脊柱转移，阳性率66．7％，阳性者病理符合率100％；PET阴性者14例中，假阴性4例，其中2例为肺部结节，其结节直径均小于1cm，1例为纵隔淋巴结，1例为脊柱骨转移，阴性符合率71．4％。结论：PET在肺部肿块及结节的诊断、鉴别诊断以及肺癌合并多病灶时的分期有较高的价值，但小于1cm的结节PET检查意义不大，脊柱转移有假阴性可能。     

正电子发射计算机断层显像-计算机断层扫描联合磁共振成像对直肠癌淋巴结转移的诊断价值分析

目的 探讨正电子发射计算机断层显像-CT(PET-CT)联合MRI对直肠癌淋巴结转移的诊断价值.方法 收集80例经手术病理结果确诊为直肠癌的患者的病历资料,所有患者在手术治疗前采取PET-CT与MRI检查,比较PET-CT、MRI、PET-CT联合MRI检查对直肠癌淋巴结转移与非淋巴结转移的诊断结果,以手术病理结果为金标准,比较3种检查结果与手术病理结果的一致性,并绘制受试者工作特征(ROC)曲线分析3种检查方式对直肠癌淋巴结转移的诊断价值.结果 PET-CT检查显示,转移淋巴结最大标准摄取值(SUVmax)、最小标准摄取值(SUVmin)均明显高于非转移淋巴结,MRI检查显示,转移淋巴结标准表观弥散系数(ADCstandard)、最慢表观弥散系数(ADCslow)、最快表观弥散系数(ADCfast)均明显低于非转移淋巴结,PET-CT联合MRI检查显示,转移淋巴结长径、短径均明显长于非转移淋巴结,差异均有统计学意义(P﹤0.01).PET-CT检查与手术病理结果的一致性为85.00％(68/80),MRI检查与手术病理结果的一致性为77.50％(62/80),PET-CT联合MRI检查与手术病理结果的一致性为95.00％(76/80).PET-CT联合MRI检查诊断直肠癌淋巴结转移的灵敏度、特异度、准确度均明显高于PET-CT或MRI单独检查.结论 PET-CT联合MRI具有较高的直肠癌淋巴结转移诊断价值,也是直肠癌淋巴结转移分期的重要依据,可为治疗提供重要依据.     

正电子发射断层显像在心脏恶性肿瘤诊断中的临床应用价值

目的:探讨正电子发射断层显像(PET/CT)在心脏肿瘤诊断中的临床应用价值.方法:回顾性分析2011年1月-2018年12月,在我中心行PET/CT检查的23例心脏肿瘤患者的全身PET/CT的诊断结果,确诊依据为术后病理结果、临床随诊结果证实,评价PET/CT对心脏肿瘤诊断效能.结合影像学特征及SUVmax得到PET/...     

^18氟-脱氧葡萄糖正电子发射计算机断层显像寻找未知原发灶肿瘤原发灶的临床价值

目的研究”氟一脱氧葡萄糖正电子发射计算机断层显像（^18F－FDGPET－CT）在寻找原发灶不明转移癌（CUP）患者原发灶中的临床价值。方法回顾性分析为寻找原发灶而行^18F-FDGPET．CT扫描的CUP患者48例,其中男28例,女20例;年龄41-82岁,平均（57±16）岁。依据转移癌部位不同将患者分为颈部淋巴结转移组（28例）及非颈部淋巴结转移组（20例）,计算并比较^18F-FDGPET-CT诊断各组原发灶的灵敏度。结果^18F-FDGPET-CT寻找CUP患者原发病灶的灵敏度为66．7％（32／48）,寻找颈部淋巴结转移CUP患者的灵敏度为78．6％（22／28）,非颈部淋巴结转移CUP患者的灵敏度为50．0％（10／20）;^18F-FDGPET-CT诊断颈部淋巴结转移组CUP患者原发灶的灵敏度与非颈部淋巴结转移组相比,差异有统计学意义（x。4．286,P〈0．05）。结论^18F-FDGPET-CT诊断CUP患者原发灶灵敏度较高,尤其适用于颈部淋巴结转移的CUP患者。、     

核医学正电子断层显像在肾肿瘤患者术前诊断中的作用

目的探讨PET在肾肿瘤术前诊断中作用。方法回顾性分析134例肾肿瘤患者PET图像。134例肾肿瘤术前评估患者中,32例行常规氟-18脱氧葡萄糖(18F-fluorodeoxyglucose,18F-FDG)PET或PET/CT显像(以下简称FDG-PET),51例行FDG-PET双时相显像,51例1周内分别行FDG-PET及碳-11乙酸盐(11C-acetate,AC)PET或PET/CT(以下简称AC-PET)双核素检查。收集其临床资料和影像检查结果。以病理结果为金标准。结果 FDG-PET对肾原发恶性肿瘤总的诊断准确率为48.5%,阳性预测值为96.3%,对透明细胞癌诊断准确率最低,为28.6%。对肾盂癌及其他恶性肿瘤诊断准确率为92.9%和75.0%。AC-PET对透明细胞癌诊断准确率93.5%。FDG-PET双时相显像60.0%阳性病灶标准摄取值(standard uptake value,SUV)升高,2例阴性病灶变为阳性。20例PET检查前其他检查发现肾外病灶的患者,检查后排除4例,并新发现6例患者肾外转移病灶。结论 FDG-PET检查对肾盂癌及其他恶性肿瘤诊断准确性高,对肾实质肿瘤诊断能力差,对肾肿瘤患者术前分期有帮助。AC-PET可弥补FDG-PET的不足。FDG-PET双时相显像不能从根本上解决FDG-PET对肾肿瘤诊断假阴性的问题。     

18F-脱氧葡萄糖正电子发射计算机断层显像对淋巴瘤分期和预后评估的作用

 【摘要】　目的　探讨18F-脱氧葡萄糖正电子发射计算机断层显像（FDG-PET）对淋巴瘤患者分期及预后评估的作用。 方法 对初诊的41例淋巴瘤患者,化疗前和化疗4个疗程后行FDG-PET,中位随访30个月,比较化疗前FDG-PET分期和化疗4个疗程后FDG-PET结果对预后的影响。 结果 41例患者治疗前结内、外病灶的最大标准摄取值（SUVmax）分别为9.7±6.9和8.4±6.8。侵袭性非霍奇金淋巴瘤（NHL）和惰性NHL比较,结内、外病灶的SUVmax值差异有统计学意义（侵袭性NHL分别为10.3±7.5和9.1±6.5,惰性NHL分别为4.7±2.1和2.4±0.6,均P<0.05）。NHL和霍奇金淋巴瘤（HL）、B细胞和T细胞NHL、活化B与生发中心来源弥漫大B细胞淋巴瘤治疗前FDG-PET的SUVmax差异无统计学意义（P>0.05）。化疗前 22例（54 ％）患者FDG-PET检出结外器官病变;6例（15 ％）因FDG-PET发现CT等其他检查未显示的淋巴结或结外病变而提高临床分期。治疗前经FDG-PET分期为Ⅰ、Ⅱ期的患者15例（37 ％）,Ⅲ、Ⅳ期的患者26例（63 ％）。随访期间,FDG-PET分期Ⅰ、Ⅱ期的患者中1例（7 ％）因疾病进展死亡,Ⅲ、Ⅳ期的患者中6例（23 ％）因疾病进展死亡。41例患者化疗4个疗程后行FDG-PET检查,FDG-PET阴性的患者17例（41 ％）中,随访期间1例（6 ％）因疾病复发死亡,FDG-PET阳性的患者24例（59 ％）中,随访期间6例（25 ％）因疾病进展死亡。 结论　化疗前FDG-PET检查有助于对淋巴瘤患者进行准确的临床分期,化疗4个疗程后FDG-PET检查有助于评估淋巴瘤患者的预后,指导进一步治疗。     

PET-CT对肺癌骨转移诊断的研究进展

 正电子发射型计算机断层扫描仪 (PET)-CT对诊断肺癌骨转移有重要的作用,它可以反映肺癌骨转移病灶的病理生理变化及形态结构变化。PET-CT全身显像对肺癌骨转移诊断的敏感性、特异性及准确性均高于X线片、CT、磁共振成像（MRI）和单光子发射计算机断层（SPECT）等传统的肺癌骨转移临床诊断方法。     

18 F-PSMA-1007 PET/CT对前列腺癌根治术后生化复发患者早期诊断评估和临床治疗决策影响的价值研究

背景与目的： ¹⁸ F-前列腺特异性膜抗原（prostate-specific membrane antigen,PSMA）-1007正电子发射计算机体层显像（positron emission tomography and computed tomography,PET/CT）是目前前列腺癌（prostate cancer,PCa）评估的先进分子影像学手段。探讨 ¹⁸ F-PSMA-1007 PET/CT对PCa根治术（radical prostatectomy,RP）后生化复发（biochemical recurrence,BCR）患者临床复发和转移的早期检出率以及对临床治疗决策的影响。方法：总结分析2018年12月—2020年12月四川省肿瘤医院收治的行RP后BCR并行 ¹⁸ F-PSMA-1007 PET/CT检查的51例PCa患者的资料,采用感兴趣区方法半定量计算分析肿瘤放射性摄取,以最大标准化摄取值（maximum standardized uptake value,SUV _max ）表示。评估其对BCR患者临床复发和转移灶［局部复发（前列腺床）、淋巴结转移（盆腔、腹膜后和膈上等）、骨转移和内脏转移（如肺）］的检出率,进一步分别比较不同前列腺特异性抗原（prostate-specific antigen,PSA）水平组间和原Gleason评分组间检出率的差异。结果：51例患者的中位年龄为66岁（52~80岁）,初诊时血清中位PSA为35 ng/mL（6~224 ng/mL）。所有患者均为前列腺腺泡腺癌,其中1例伴导管内癌,1例伴导管腺癌,1例伴黏液腺癌,1例伴印戒样成分,1例伴神经内分泌分化。Gleason评分≤7分22例（43.14%）,Gleason评分≥8分29例（56.86%）。BCR发生的中位时间为15个月（3~62个月）,BCR时中位PSA为0.58 ng/mL（0.2~110.0 ng/mL）,其中0.2 ng/mL≤PSA ＜ 0.5 ng/mL 21例（41.18%）,0.5 ng/mL≤PSA ＜ 1.0 ng/mL12例（23.53%）,1.0 ng/mL≤PSA ＜ 2.0 ng/mL 4例（7.84%）,PSA≥2.0 ng/mL 14例（27.45%）。检查发现无临床局部复发或转移7例（13.73%）,临床局部复发或转移44例（86.27%）,其中9例（20.45%）前列腺术区复发,28例（63.64%）不同部位淋巴结转移,31例（70.45%）骨转移,2例（4.55%）内脏转移,此外还有2例皮下结节转移及1例阴茎根部转移。所有复发或转移灶的中位SUV _max 为17.9（1.4~110.9）,局部复发灶的中位SUV _max 为14.0（3.2~110.9）,淋巴结转移灶的中位SUV _max为10.2（2.0~90.1）,骨转移灶的中位SUV max 为5.4（1.4~109.6）。0.2 ng/mL≤PSA ＜ 0.5 ng/mL组（21例）、0.5 ng/mL≤PSA ＜ 1.0 ng/mL组（12例）、1.0 ng/mL≤PSA ＜ 2.0 ng/mL组（4例）和PSA≥2.0 ng/mL组（14例）的复发或转移检出率分别为71.43%（15/21）、100.00%（12/12）、75.00%（3/4）和100.00%（14/14）,不同PSA水平组间检出率差异无统计学意义（P＞0.05）。原Gleason评分≤7分组（22例）和Gleason评分≥8分组（29例）的复发或转移检出率分别为68.18%（15/22）和100.00%（29/29）,不同Gleason评分组间检出率差异有统计学意义（P ＜ 0.05）。临床治疗方面,采用观察等待4例（7.84%）,单纯内分泌治疗18例（35.29%）,单纯挽救性放疗（salvage radiotherapy,SRT）2例（3.92%）,内分泌治疗联合SRT 24例（47.06%）,内分泌治疗联合多西他赛全身化疗1例（1.96%）,挽救性盆腔淋巴结清扫术2例（3.92%）,最终共有30例（58.82%）患者改变原临床治疗决策。结论： ¹⁸ F-PSMA-1007 PET/CT对RP后BCR患者临床复发或转移具有很好的早期诊断价值和效能,有利于此类患者的精准评估和制定最优的治疗方案,并显著影响临床治疗决策。     

氟-18-脱氧葡萄糖正电子发射体层摄影术对胸部恶性肿瘤诊断价值的初步评价

背景与目的 氟-18-脱氧葡萄糖正电子发射体层摄影术(18 F-fluorodeoxyglucose positron emission tomography,18F-FDG PET)被认为是除病理诊断之外对胸部恶性肿瘤最有价值的诊断方法之一.然而在临床工作中,18F-FDG PET诊断同病理诊断不符的病例并不罕见.本研究的目的是对18F-FDG PET在胸部恶性肿瘤诊断中的价值作初步评价.方法 收集在西安地区行18F-FDG PET检查,并通过手术、经皮穿刺活检、经支气管镜活检、胸水涂片等方法获得病理诊断的胸部肿瘤患者51例.对比其18F-FDG PET诊断及最终病理诊断的结果,并计算PET对胸部恶性肿瘤诊断的功效率、敏感性、特异性、假阳性率、假阴性率、阳性预示值、阴性预示值.结果 18F-FDG PET诊断与最终病理诊断相符合者共34例,其中真阳性31例,真阴性3例.不符者共有17例,其中假阳性11例,病理诊断分别为:结节病2例,肺结核病6例,肺内炎性假瘤2例,肺隐球菌病1例;假阴性6例.计算得出其各项评价指标分别为:功效率66.67%,敏感性83.78%,特异性21.43%,假阳性率78.57%,假阴性率16.22%,阳性预示值73.81%,阴性预示值33.33%.结论 18F-FDGPET仍然是目前诊断胸部恶性肿瘤的较为先进的无创检查技术,但其对某些代谢状态较为活跃的良性疾病如结核等,难以与恶性肿瘤相鉴别.因此临床医生必须将PET诊断结果与临床实际相结合,才能最大程度发挥18F-FDG PET在胸部恶性肿瘤诊断方面的优势.     

Advancement in treatment and diagnosis of pancreatic cancer with radiopharmaceuticals

Pancreatic cancer (PC) is a major health problem. Conventional imaging modalities show limited accuracy for reliable assessment of the tumor. Recent researches suggest that molecular imaging techniques with tracers provide more biologically relevant information and are benefit for the diagnosis of the cancer. In addition, radiopharmaceuticals also play more important roles in treatment of the disease. This review summaries the advancement of the radiolabeled compounds in the theranostics of PC.     

Prognostic value of baseline FDG uptake on PET-CT in esophageal carcinoma

AIM: To evaluate the influence of baseline maximum standardized uptake value (SUV_max) on survival in a cohort of patients, undergoing positron emission tomography-computed tomography (PET-CT) scan for esophageal carcinoma.METHODS: The pre-treatment SUV_max numeric reading was determined in patients with confirmed esophageal or junctional cancer having PET-CT scan during the time period 1^st January 2007 until 31^st July 2012. A minimum follow up of 12 mo was required. Patients were subdivided into quartiles according to SUV_max value and the influence of SUV_max on survival was assessed using univariate and multivariate analysis. The following pre-treatment factors were investigated: patient characteristics, tumor characteristics and planned treatment.RESULTS: The study population was 271 patients (191 male) with esophageal or junctional carcinoma. The median age was 65 years (range 40-85) and histologic subtype was adenocarcinoma in 197 patients and squamous carcinoma in 74 patients. The treatment intent was radical in 182 and palliative in 89 patients. SUV_max was linked to histologic subtype (P = 0.008), tumor site (P = 0.01) and Union for International Cancer Control (UICC) stage (P < 0.001). On univariate analysis, prognosis was significantly associated with SUV_max (P = 0.001), T-stage (P < 0.001) and UICC stage (P < 0.001). On multivariate analysis, only T-stage and UICC stage remained significant.CONCLUSION: Pretreatment SUV_max was not a useful marker in isolation for determining prognosis of patients with esophageal carcinoma.     

^18F-FDG PET/CT在结直肠癌诊断和治疗中的价值

结直肠癌在我国是常见的恶性肿瘤,发病率逐年上升,但近30年的治疗效果进步不大,因而,术前早期正确的诊断和分期、术后检测复发转移以及判断治疗效果,对于个体化的治疗意义重大.集解剖和功能显像优势于一身的^18F-FDG PET/CT显像在结直肠癌诊断和治疗上具有广泛的应用前景和价值.大多数结直肠癌病变在PET上表现为高度的浓聚灶,^18F-FDG PET/CT对于结直肠原发灶诊断准确率一般在92.7%～95%之间,其敏感度高,假阴性率低.18F-FDG PET/CT可以早期发现转移病灶,是目前最好的术前分期手段;对结直肠癌复发及转移诊断的灵敏度、特异性及准确性分别为89%～94.6%、83.3%～100%、90%～98.3%,显著优于传统的检查方式,可以发现更多微小或隐匿的复发和转移灶.此外,PET/CT可以通过病灶代谢的变化先于超声、CT、MRI等形态学手段早期判定化疗效果,指导临床及时更改治疗方案以及进行术前再分期.总之,PET/CT为结直肠癌的诊断、术前分期、监测术后复发转移、评估疗效提供了一种安全无创的功能影像方法.     

膀胱混合癌的诊断和治疗

 目的　提高膀胱混合癌的诊治水平。方法　回顾分析 1 990年 1月至 2 0 0 0年 6月收治的 1 2例病人 ,结合文献就其临床表现、诊断和治疗以及预后情况进行讨论。结果　 1 2例膀胱混合癌占同期 5 49例膀胱肿瘤的 2 .1 9% ,其中鳞、腺混合癌 3例 ,移行、鳞状、腺细胞混合癌 1例 ,移行、鳞状细胞混合癌 6例 ,移行、腺细胞癌混合癌 2例。行膀胱部分切除术 9例 ,全膀胱切除 2例 ,根治性全膀胱切除 1例。术后 1 2例患者均接受定期随访 ,生存期 7个月～ 4.2年。结论　膀胱混合癌的恶性程度高 ,预后极差 ,手术切除仍是主要的治疗方法 ,早期诊断是提高生存率的关键     

Defining the role of PET-CT in staging early breast cancer

Introduction.

Currently, there is a lack of data on the role of combined positron emission tomography–computed tomography (PET–CT) in the staging of early invasive primary breast cancer. We therefore evaluated the role of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG)-PET–CT in this patient population.

Methods.

We prospectively recruited 70 consecutive patients (69 women, one man; mean age, 61.9 ± 8.1 years) with early primary breast cancer for staging with ¹⁸F-FDG-PET–CT. All PET–CT images were interpreted by two readers (independently of each other). A third reader adjudicated any discrepancies. All readers had ≥5 years of specific experience. Ethics board approval and informed consent were obtained.

Results.

The mean clinical follow-up was 22.7 ± 12.6 months. The primary tumor was identified with PET–CT in 64 of 70 patients. Of the unidentified lesions, surgical pathology revealed two intraductal carcinomas, one invasive tubular carcinoma, and three invasive lobular carcinomas. Undiagnosed multifocal breast disease was shown in seven of 70 patients. PET–CT identified avid axillary lymph nodes in 19 of 70 patients, compared with 24 of 70 confirmed during surgery. There were four patients who were axillary node positive on PET but had no axillary disease at surgery.Five patients were reported with avid metastases. Two of those patients were treated for metastatic disease (nodal, lung, and liver in one and bone metastases in the other) following further imaging and clinical assessment. In the other three patients, lesions (lung, n = 1; pleural, n = 1; paratrachael node, n = 1) were subsequently diagnosed as benign lesions.

Conclusion.

Integrated ¹⁸F-FDG-PET–CT may have a role in staging patients presenting with early breast cancer.     

A meta-analysis exploring the role of PET and PET-CT in the management of potentially resectable colorectal cancer liver metastases

BackgroundPositron emission tomography (PET), alone or combined with computed tomography (CT), potentially enhances detection of occult metastatic colorectal cancer.MethodsWe compared the impact of PET/PET-CT with conventional imaging, versus conventional imaging alone, in patients with potentially resectable colorectal cancer liver metastases. MEDLINE, EMBASE, and CENTRAL were searched for studies investigating PET/PET-CT to determine resectability. Outcomes included overall (OS), disease-free survival (DFS), change in surgical management, and futile laparotomy. Evidence quality was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. A pre-specified protocol was registered in PROSPERO.ResultsOf 4034 articles, two randomized trials (n = 554), and 11 non-randomized studies (n = 2251) were included. PET/PET-CT did not improve OS (hazard ratio [HR] 0.94, 95% CI 0.69–1.26, moderate quality) or DFS (HR 1.01, 95% CI 0.82–1.26, moderate quality). In the two trials, PET/PET-CT changed surgical management in 8% of cases (95% CI 5–11%, high quality), and did not significantly reduce futile laparotomies (risk ratio 0.59, 95% CI 0.24–1.47, low quality). Among non-randomized studies, PET/PET-CT changed surgical management in 20% of cases (95% CI 17–22%, very low quality) and reduced futile laparotomies (odds ratio 0.51, 95% CI 0.32–0.81, very low quality).ConclusionsModerate-quality evidence suggests that preoperative PET/PET-CT does not improve OS or DFS in patients with colorectal cancer liver metastases. These results do not support routine use of PET/PET-CT in patients with potentially resectable disease. The main limitation of this study was the lack of randomized studies.     

The role of F-fluorodeoxyglucose positron emission tomography in the diagnosis, staging, and follow-up of cholangiocarcinoma

¹⁸F-Fluorodeoxyglucose positron emission tomography (¹⁸FDG-PET) is a new diagnostic technique for the diagnosis and staging of cholangiocarcinoma. For diagnosis of a primary cholangiocarcinoma, ¹⁸FDG-PET seems to be helpful to discriminate between malignant and benign lesions. However, the accuracy of ¹⁸FDG-PET seems to be dependent on the anatomic location, growth pattern, and pathologic characteristics of the lesion. It has been proved that the accuracy of ¹⁸FDG-PET is limited to detection of extrahepatic, infiltrating, and mucinous cholangiocarcinomas. Due to its lower sensitivity, ¹⁸FDG-PET provides complementary rather than confirmative information in the diagnosis of regional lymph node metastasis. In contrast, it has high accuracy in detecting unsuspected distant metastases. The role of ¹⁸FDG-PET in detecting cancer recurrence, monitoring treatment response, and predicting prognosis is still controversial.