The role of gallium 67 imaging in non-Hodgkin's lymphoma of the gastrointestinal tract

To evaluate the clinical usefulness of gallium 67 imaging in the detection of gastrointestinal (GI) non-Hodgkin's lymphoma (NHL) and in the assessment of the therapeutic effects, images were reviewed in 24 cases (25 lesions: stomach, 20; ileum, 2; and terminal ileum and or cecum, 3) and were compared using barium studies and, in 16 cases, computerized tomography (CT). In all, 23 (92.0%) of the 25 lesions were detected by 67Ga citrate imaging, the barium studies detected all 25, and CT detected 15 of 16 lesions (93.8%). The two lesions not identified by imaging and the one not found by CT were the smallest of all. In 2 (8.7%) of the 23 lesions positively identified by 67Ga-citrate imaging, both CT and imaging revealed the extent of the tumor more accurately than did the barium studies. In all but one of the patients, a close correlation existed between the imaging results and the therapeutic effects. These data suggest that 67Ga imaging is useful in conjunction with CT and barium studies for the detection of GI NHL and for the assessment of both the spatial extent of disease and the therapeutic effects, although a lack of 67Ga uptake after therapy does not always indicate a good therapeutic effect.     

The role of gallium-67 citrate scintigraphy in gastro-intestinal malignant lymphoma

To evaluate the clinical usefulness of gallium-67 scintigraphy in the detection of the gastrointestinal (GI) non-Hodgkin's lymphoma (NHL) and in the assessment of the therapeutic effects, gallium-67 scintigraphy was reviewed on 24 cases (25 lesions; stomach in 20, ileum in 2, and terminal ileum and/or cecum in 3). Twenty-three out of the 25 lesions (92.0%) were detected by gallium-67 scintigraphy, while barium study could detect all of the 25 lesions. The sizes of the gallium-67 negative 2 lesions were the smallest of all (2.5 and 3.0 cm). The tumor size was considered to the most important factor in the detection by gallium-67 scintigraphy, while the histological classification and the location of the tumor were not related to its detectability. Findings in follow-up gallium-67 scintigraphy after therapy on 10 cases were correlated well with the therapeutic effects. These data suggest that gallium-67 scintigraphy is useful for the detection of GI involvement of NHL and for the assessment of therapeutic effects.     

Gallium-67 imaging in the diagnosis of blastomycosis

⁶⁷Ga imaging was used in a group of 13 untreated patients with documented South American blastomycosis in an attempt to obtain additional information on the site and extent of the lesions. All diagnoses were confirmed by demonstration of the fungi in the lesions or body fluids. Serologic tests were performed on all patients. ⁶⁷Ga imaging was correlated with X-ray in all patients, and with bone imaging when bony lesions were suspected. ⁶⁷Ga imaging was positive for all lesions detected on chest X-ray and by clinical evaluation. More importantly, lesions clinically unsuspected and missed by other diagnostic techniques were shown on ⁶⁷Ga imaging: bony and hepatic lesions in three patients; a brain lesion in one patient and parotid gland involvement in five patients. There was good agreement between ⁶⁷Ga imaging and clinical and laboratory data, scintigraphy being more sensitive. Follow-up studies after specific therapy demonstrated decreased uptake in the lungs and other sites. ⁶⁷Ga imaging is a useful tool for detection of suspected and unsuspected lesions of blastomycosis and to evaluate the response of the disease to specific therapy.     

胃肠道恶性淋巴瘤影像学诊断

简要介绍恶性淋巴瘤分类的进展及最新的病理分类（修订的欧美淋巴瘤分类－REAL Classification 1994;世界卫生组织分类－－WHO Classification 1998),约20％非霍奇金淋巴瘤（non-Hodgkin's lymphoma NHL)原发于淋巴结外,其中以胃肠道最为常见,胃肠道淋巴 瘤中胃最多见,继为小肠,结,直肠,食管最为罕见,胃肠道NHL主要在黏膜下生长蔓延浸润,可局部形成结节或肿块,也可有溃疡形成,多灶病变占10％－40％,原发和继发胃肠道NHL的影像表现主要反映了大体病理改变,原发和继发的影像表现相同,CT扫描可显示消化道壁的改变,有无腹腔或腹膜后淋巴结肿大,但单纯依靠观察胃肠道壁的厚度,淋巴结是否肿大对鉴别淋巴瘤与消化道癌的意义不大,仍需结合胃肠造影,临床表现,胃镜活检等综合考虑。     

Whole-body hybrid PET with 18F-FDG in the staging of non-Hodgkin's lymphoma.

PET with a double-head gamma camera (hybrid PET) is a new approach to tumor imaging with 18F-FDG. This study was conducted to clarify the feasibility of whole-body FDG hybrid PET in the staging of non-Hodgkin's lymphoma (NHL) in comparison with PET with a dedicated camera (dedicated PET) and to compare the results of both FDG studies with those of CT and 67Ga scanning as conventional imaging studies (CIS). METHODS: Thirty patients with NHL were prospectively evaluated. The results of the imaging studies regarding detection of the sites involved and staging were compared with each other and with those of the reference standard based on the final overall clinical evaluation. RESULTS: Of the total of 206 sites, whole-body FDG hybrid PET and dedicated PET detected 159 sites (77.2%) and 179 sites (86.9%), respectively. Eighteen of the 20 sites missed by hybrid PET alone consisted of lesions < 1.5 cm. Both FDG studies provided concordant staging results in all but 2 patients. CIS, on the other hand, detected 164 (79.6%) of the 206 sites, 137 of which were also detected by hybrid PET. Hybrid PET detected an additional 22 sites not found by CIS, whereas CIS detected 27 additional sites. Hybrid PET and CIS provided concordant staging results in 19 patients. Hybrid PET correctly staged NHL in 5 additional patients, whereas CIS correctly staged NHL in only 1 additional patient. CONCLUSION: Whole-body FDG hybrid PET appeared to be an accurate method of staging NHL. Despite its poorer image quality compared with dedicated PET, hybrid PET provided NHL staging results comparable with those of dedicated PET. Hybrid PET also yielded results comparable with those of CIS. However, whole-body FDG hybrid PET is currently inadequate as a single modality for staging NHL and is complementary to CT.     

胃肠道淋巴瘤的多层螺旋CT影像学分析

目的 回顾分析胃肠道淋巴瘤多层螺旋CT表现.资料与方法 回顾61例胃肠道淋巴瘤患者的多层螺旋CT扫描资料,分析其相关CT表现,并对病变的厚度、分期、平扫和增强CT值与及其病变发生部位和病理结果 之间的关系进行分析和对比.结果 胃肠道淋巴瘤大多表现为胃肠壁的弥漫性增厚及周围淋巴结增大;动脉瘤样扩张和病灶内积气是回肠淋巴瘤的特征性表现;黏膜相关性淋巴瘤(MALT)多见于胃部,且病变厚度较其他类型淋巴瘤略薄.结论 多层螺旋CT是诊断胃肠道淋巴瘤的有效手段,特别是回肠淋巴瘤有较为特异的表现.     

Gallium-67 scintigraphy in lymphoma: is there a benefit of image fusion with computed tomography?

The usefulness and complementarity of gallium (67Ga) scintigraphy and computed tomography (CT) in the management of patients with lymphoma have been extensively demonstrated. Owing to a lack of anatomical landmarks and physiological distribution of the tracer, precise localisation of abnormalities on 67Ga scintigraphy can be difficult. As fusion imaging techniques between single-photon emission tomography (SPET) and CT have been developed recently, we investigated whether use of CT/67Ga SPET fusion imaging could help in the interpretation of 67Ga scintigraphy. From November 1999 to May 2001, 52 consecutive fusion studies were performed in 38 patients [22 patients with Hodgkin's disease (HD) and 16 patients with non-Hodgkin's lymphoma (NHL)] as part of pre-treatment staging (n=13), treatment evaluation (n=20) or evaluation of suspected recurrence (n=19). 67Ga scintigraphy was carried out 2 and 6 days following the injection of 185-220 MBq 67Ga citrate. On day 2, 67Ga SPET and CT were performed, focussing on the chest and/or the abdomen/pelvis. Data from each imaging method were co-registered using external markers. 67Ga scintigraphy and CT were initially interpreted independently by nuclear medicine physicians and radiologists. CT/67Ga SPET fusion studies were then jointly interpreted and both practitioners indicated when fusion provided additional information in comparison with CT and 67Ga SPET alone. Image fusion was considered to be of benefit in 12/52 (23%) studies which were performed for initial staging (n=4), treatment evaluation (n=4) or evaluation of suspected recurrence (n=4). In these cases, image fusion allowed either confirmation and/or localisation of pathological gallium uptake (n=10) or detection of lesions not visible on CT scan (n=2). Fusion was relevant for discrimination between osseous lesions and lymph node involvement adjacent to bone, especially in the thoracic and lumbar spine and pelvis. In the abdomen and pelvis, fusion helped to differentiate physiological bowel elimination from abnormal uptake, and assisted in precisely locating uptake in neighbouring viscera of the left hypochondrium, including the spleen, left liver lobe, coeliac area, stomach wall and even the splenic flexure. At the thoracic level, fusion also proved useful for demonstrating clearly the relationships of abnormal foci to the pleura, hepatic dome, mediastinum, ribs or thoracic spine. Clinical management was altered by fusion imaging in one patient (chemotherapy was given instead of radiotherapy) and was potentially affected in three other patients (in that, in conjunction with other factors, the results of fusion imaging had an influence on the decision regarding use of irradiation and especially the treatment volume). In conclusion, CT/67Ga SPET fusion imaging allowed precise localisation of gallium uptake and correct attribution to the involved viscera, thereby altering the diagnosis in 20%-25% of studies in comparison with CT and 67Ga SPET analyses alone. CT/67Ga SPET fusion therefore appears valuable in facilitating the interpretation of 67Ga scintigraphy and we recommend its use in patients with lymphoma when CT and 67Ga scintigraphy are planned.     

Clinical relevance of gallium-67 scintigraphy in lymphoma before and after therapy

The clinical impact of gallium-67 scintigraphy before and after therapy for lymphoma remains controversial. The aims of this study were: (1) to compare the staging of lymphoma by ⁶⁷Ga scintigraphy only with staging by clinical examination and conventional imaging (CI), and (2) to analyse the clinical relevance of both ⁶⁷Ga imaging and CI after treatment. From March 1995 to November 1998, 86 ⁶⁷Ga scintigraphy studies were performed in 62 patients with Hodgkin’s disease (n=52) or non-Hodgkin’s lymphoma (n=10). ⁶⁷Ga scintigraphy was performed at diagnosis (n=44) or after therapy (n=42) using 185–220 MBq ⁶⁷Ga citrate and planar and single-photon emission tomography (SPET) studies. Treatment comprised radiotherapy, chemotherapy or combined modalities. CI included plain chest radiography, computed tomography (CT) of the chest and abdomen/pelvis, ultrasound of the abdomen, lymphography, bone marrow biopsy and, when necessary, magnetic resonance imaging (MRI) and bone scintigraphy. For individual suspected sites of disease before treatment, complete agreement between clinical examination and CI on the one hand and ⁶⁷Ga scintigraphy on the other hand was observed in 25/44 patients (57%; 95% confidence interval 41%–72%). Clinical examination and CI showed more sites than did ⁶⁷Ga scintigraphy in 12/44 patients (27%) and ⁶⁷Ga imaging demonstrated more sites than CI in 6/44 patients (11%). The clinical stage of the disease as assessed using ⁶⁷Ga scintigraphy only was in agreement with that using all diagnostic procedures in 34/44 patients (77%; 95% confidence interval 62%–89%). Compared with CI staging, ⁶⁷Ga scintigraphy downstaged seven patients (16%) and upstaged three (7%). ⁶⁷Ga scintigraphy downstaged mainly because of the limited value of the technique below the diaphragm and upstaged owing to the good sensitivity in the lung. After therapy, both CI and ⁶⁷Ga scintigraphy were normal in 11 patients. All but one of these patients were in complete remission after a median follow-up of 31 months. In contrast, radiological residual mass was observed in 31/42 patients. ⁶⁷Ga imaging was normal in 22/31 (71%); 17 of these 22 patients, including nine with a large residual mass (≥2 cm), were in complete remission after a median follow-up of 32 months, while four suffered relapses 8–45 months later. The cause of death remained unknown in one patient. ⁶⁷Ga scintigraphy showed abnormal uptake in 9 of the 31 patients with a large residual mass. Active disease was demonstrated in eight patients and one patient was in complete remission 30 months thereafter. Our data show that ⁶⁷Ga imaging cannot replace CI in initial staging but can demonstrate additional individual sites of disease in more than 10% of patients and can lead to clinical upstaging with potential prognostic and therapeutic consequences. After therapy, ⁶⁷Ga scintigraphy has a clinical impact when radiological abnormalities persist because it can either avoid unnecessary complementary treatment or confirm the need to change treatment modalities. Received 5 July and in revised form 9 September 1999     

Gallium uptake in cerebrotendinous xanthomatosis

In a patient with cerebrotendinous xanthomatosis, a rare familial sterol storage disease, increased uptake of gallium-67 was observed in the tendon xanthomas. This is considered to have resulted from the tumour-like proliferation of histiocytic cells in the xanthomas. Abnormalities in the white matter of the cerebellum and the brain stem observed by X-ray computed tomography and magnetic resonance imaging were not detected by⁶⁷Ga scintigraphy, possibly due to the small size of the CNS lesions.     

Detection of bone marrow and extramedullary involvement in patients with non-Hodgkin’s lymphoma by whole-body MRI: comparison with bone and <Superscript>67</Superscript>Ga scintigraphies

The aim of this study was to evaluate the diagnostic potential of whole-body MRI (WB-MRI) for the detection of bone marrow and extramedullary involvement in patients with non-Hodgkins lymphoma. WB-MRI, which was performed on 34 patients, consisted of the recording of T1-weighted spin-echo images and a fast STIR sequence covering the entire skeleton. The WB-MRI findings for bone marrow and extramedullary involvement were compared with those from ⁶⁷Ga and bone scintigraphies and bone marrow biopsy results. Two MRI specialists reviewed the WB-MRI results and two expert radiologists in the field of nuclear medicine reviewed the bone and ⁶⁷Ga scintigraphy findings. Bone marrow and extramedullary involvement of non-Hodgkins lymphoma were confirmed by follow-up radiographs and CT and/or a histological biopsy. The detection rate of WB-MRI was high. More bone marrow involvement was detected by biopsy, and more lesions were detected by scintigraphies. In total, 89 lesions were detected by WB-MRI, whereas 15 were found by biopsy, 5 by ⁶⁷Ga scintigraphy, and 14 by bone scintigraphy. WB-MRI could also detect more extramedullary lesions than ⁶⁷Ga scintigraphy; i.e., 72 lesions were detected by WB-MRI, whereas 54 were discovered by ⁶⁷Ga scintigraphy. WB-MRI is useful for evaluating the involvement of bone marrow and extramedullary lesions throughout the skeleton in patients with non-Hodgkins lymphoma.     

The role of gallium-67 scan in defining the extent of disease in an endemic deep mycosis,paracoccidioidomycosis: a predominantly multifocal disease

The tools currently used to evaluate the extent of paracoccidioidomycosis (PCM) may be of limited value in detecting subclinical lesions. The aim of this study was to verify the role of gallium-67 whole-body scan in evaluating the extent of disease of 65 patients with active PCM. The (67)Ga scan findings were compared with the results of clinical evaluation, chest radiography and/or high-resolution computed tomography (CT), abdominal ultrasound (US) or CT, laryngoscopy, CT or magnetic resonance imaging (MRI) of the head, and technetium-99m methylene diphosphonate bone scan, obtained before treatment. Clinically unsuspected lesions were detected by imaging procedures in 21 patients (32%), mainly in the lungs (n=11), adrenals (n=6), and superficial (n=3) and deep lymph nodes (n=14). (67)Ga scan detected 100% of the cases with subclinical involvement in the lungs. Scintigraphy was superior to chest radiography in demonstrating lung disease (94% vs 81%). The lymphatic lesions were demonstrated by (67)Ga scan in all the clinically suspected cases and in nearly all unsuspected cases, and also revealed more extensive involvement than was clinically suspected in many of them. There was good agreement between (67)Ga scan and the other imaging procedures for the initial detection of thoracic and abdominal lymph nodes and bone involvement. (67)Ga imaging detected most cases of laryngopharyngeal disease with active inflammatory lesions found at indirect laryngoscopy. On the other hand, (67)Ga scan failed to demonstrate most of the adrenal and CNS lesions detected by abdominal US/CT and head CT/MRI. In conclusion, (67)Ga imaging is a useful tool for evaluating the location and extent of suspected and unsuspected lesions in PCM. It could serve as a screening method before the use of other diagnostic procedures, particularly in the detection of lung, superficial and deep lymph node and bone involvement.     

Retrospective review: usefulness of a number of imaging modalities including CT, MRI, technetium-99m pertechnetate scintigraphy, gallium-67 scintigraphy and F-18-FDG PET in the differentiation of benign from malignant parotid masses

Objective The aim of this study is to evaluate an imaging approach using computed tomography (CT), magnetic resonance imaging (MRI), technetium-99m pertechnetate scintigraphy (^99mTc pertechnetate scintigraphy), gallium-67 scintigraphy (⁶⁷Ga scintigraphy) and fluorine-18 fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET). Material and Methods We reviewed retrospectively 59 patients with parotid masses. CT, MRI,⁶⁷Ga scintigraphy,^99mTc pertechnetate scintigraphy, and¹⁸F-FDG PET were performed. Results All of the benign tumors had smooth margins on CT and MRI. Patients with inflammatory lesions and malignant lesions showed well-defined margins or ill-defined margins. All Warthin's tumors showed high technetium accumulation. Many of malignant tumors showed high FDG accumulation. Both pleomorphic adenomas and Warthin's tumors showed high accumulation in some cases on¹⁸F-FDG PET. Among 15 patients with pleomorphic adenoma, 14 patients showed marked hyperintensity relative to CSF on T2-weighted images and partial enhancement on contrast-enhanced T1-weighted images. Combination of several imaging modarity offered usefulness of differential diagnosis for parotid masses. Conclusion An efficient combination of imaging methods may be helpul for achieve the correct diagnosis.     

67Ga-SPECT/CT with a hybrid system in the clinical management of lymphoma

Purpose The purpose of this study was to investigate the added value of co-registered fusion imaging using a hybrid system in patients with lymphoma.Methods Twenty-four lymphoma patients underwent ⁶⁷Ga-SPECT/CT using a hybrid tomograph consisting of a dual-head, variable-angle gamma camera and a low-dose X-ray tube. Results were compared with those of SPECT alone.Results Forty-five lesions were identified by SPECT alone, while 49 were detected by SPECT/CT. Forty out of the 45 lesions observed on SPECT were confirmed as lymphoma, but five were due to other causes (thoracic aorta blood pool activity, sialoadenitis in the submandibular gland, bowel activity, rib fracture and bone marrow activation due to radiotherapy). SPECT/CT identified nine more neoplastic lesions compared with SPECT alone: four areas of radiopharmaceutical accumulation were observed in para-aortic lymph nodes, three in the spleen, one in the liver and one in para-iliac lymph nodes. In five cases, SPECT/CT provided additional anatomical information over SPECT alone. In four patients, four large areas of ⁶⁷Ga uptake (one mediastinal, two supraclavicular and one para-aortic) were better characterised; in one subject uptake was localised in the seventh thoracic vertebra only by SPECT/CT. Hybrid imaging provided additional data in 13 patients (54.2%), thus inducing oncologists to reconsider the therapeutic approach in eight subjects (33.2%): unnecessary treatment was avoided in four (16.6%) while therapy was altered in another four (16.6%).Conclusion SPECT/CT hybrid system is able to provide information not obtained by SPECT alone. It allows the anatomical localisation of lymphoma and physiological radiopharmaceutical uptake, facilitates the diagnosis of tumours located in the abdomen (subdiaphragmatic lesions) and provides information that may cause a change in therapeutic strategy.     

Better visualization of a lung tumour with 99mTc-DPD than with 99mTc-glucoheptonate or 67Ga-citrate

A case of a squamous cell lung carcinoma detected with ^99mTc-DPD, ⁶⁷Ga-citrate and ^99mTc-glucoheptonate (GH) is reported. The highest uptake was seen with DPD and the lowest with ⁶⁷Ga. Emission-computed tomography was very useful in DPD imaging but gave less new information in GH and ⁶⁷Ga studies in comparison to traditional planar imaging. The patient had been given both irradiation and chemotherapy, which might be the cause of good accumulation of DPD and rather poor accumulation of GH and ⁶⁷Ga.     

<Superscript>18</Superscript>p-FDG PET is superior to<Superscript>67</Superscript>Ga SPECT in the staging of non-Hodgkin’s lymphoma

OBJECTIVE: Our study aims to compare diagnostic accuracy between 18F-FDG PET and 67Ga SPECT in the staging of non-Hodgkin's lymphoma. METHODS: Twenty-eight patients with non-Hodgkin's lymphoma, underwent 18F-FDG PET, 67Ga SPECT and CT for the pretreatment staging of malignant lymphoma between August 1999 and March 2002. 18F-FDG PET imaging was obtained 60 minutes after the intravenous administration of 185 MBq of 18F-FDG. 67Ga SPECT imaging was obtained 2 days after the intravenous administration of 148 MBq of 67Ga. 18F-FDG PET and 67Ga SPECT were performed within one month. Both imagings were performed on the area from the neck to the pelvis. The 18F-FDG PET and 67Ga SPECT findings were compared with the CT findings and the clinical course. RESULTS: Sixty-six nodal lesions were clinically confirmed. Of these, 32 were identified by both 18F-FDG PET and 67Ga SPECT. The remaining 34 lesions were identified only by 18F-FDG PET. The mean (+/- SD) sizes' of the nodes were 34.7 +/- 32.4 mm for 18F-FDG-positive and 67Ga-positive lesions and 15.7 +/- 8.3 mm for 18F-FDG-positive and 67Ga-negative lesions (p < 0.001). Of the 23 extranodal lesions, 12 were identified by both 18F-FDG PET and 67Ga SPECT, whereas 6 lesions were identified by only 18F-FDG PET. Five lesions were not identified by either technique. No 18F-FDG-negative but 67Ga-positive nodal or extranodal lesions were observed. The difference in findings between the two studies is related to the difference in the size but not in the histology or site of the lesions. CONCLUSION: 18F-FDG PET detected significantly more lesions particularly small lesions than 67Ga SPECT. Thus, 18F-FDG PET is considered to be superior to 67Ga SPECT in the staging of non-Hodgkin' s lymphoma.     

Comparison of standard and delayed imaging to improve the detection rate of [<Superscript>68</Superscript>Ga]PSMA I&amp;T PET/CT in patients with biochemical recurrence or prostate-specific antigen persistence after primary therapy for prostate cancer

Purpose

The aim of this study was to assess the value of dual-time point imaging in PET/CT for detection of biochemically recurrent or persistent prostate cancer, using the prostate-specific membrane antigen (PSMA) ligand [⁶⁸Ga]PSMA I&T.

Methods

240 patients who underwent a [⁶⁸Ga]PSMA I&T PET/CT in the context of biochemical relapse of prostate cancer were included in this retrospective analysis. Imaging consisted of a standard whole-body PET/CT (1 h p.i.), followed by delayed (3 h p.i.) imaging of the abdomen. PSA-stratified proportions of positive PET/CT results, standardized uptake values and target-to-background ratios were analyzed, and compared between standard and delayed imaging.

Results

The overall detection rates of [⁶⁸Ga]PSMA I&T PET/CT were 94.2, 71.8, 58.6, 55.9 and 38.9% for PSA levels of ≥2, 1 to <2, 0.5 to <1, >0.2 to <0.5, and 0.01 to 0.2 ng/mL, respectively. Although the target-to-background ratio improved significantly over time (P?<?0.0001), the majority (96.6%) of all lesions suggestive of recurrent disease could already be detected in standard imaging. Delayed imaging at 3 h p.i. exclusively identified pathologic findings in 5.4% (10/184) of abnormal [⁶⁸Ga]PSMA I&T PET/CT scans, and exclusively detected 3.4% (38/1134) of all lesions suggestive of recurrent disease.

Conclusions

[⁶⁸Ga]PSMA I&T PET/CT shows high detection rates in patients with prostate-specific antigen persistence or biochemical recurrence of prostate cancer. Delayed imaging can detect lesions with improved contrast compared to standard imaging. However, the impact on detection rates was limited in this study.

     

Gallium-67 imaging in the diagnosis of blastomycosis

67Ga imaging was used in a group of 13 untreated patients with documented South American blastomycosis in an attempt to obtain additional information on the site and extent of the lesions. All diagnoses were confirmed by demonstration of the fungi in the lesions or body fluids. Serologic tests were performed on all patients. 67Ga imaging was correlated with X-ray in all patients, and with bone imaging when bony lesions were suspected. 67Ga imaging was positive for all lesions detected on chest X-ray and by clinical evaluation. More importantly, lesions clinically unsuspected and missed by other diagnostic techniques were shown on 67Ga imaging: bony and hepatic lesions in three patients; a brain lesion in one patient and parotid gland involvement in five patients. There was good agreement between 67Ga imaging and clinical and laboratory data, scintigraphy being more sensitive. Follow-up studies after specific therapy demonstrated decreased uptake in the lungs and other sites. 67Ga imaging is a useful tool for detection of suspected and unsuspected lesions of blastomycosis and to evaluate the response of the disease to specific therapy.     

Gallium scintigraphy in patients with adult T-cell leukemia lymphoma

Gallium scintigraphy was evaluated in 25 patients with adult T-cell leukemia lymphoma (ATLL). Anterior and posterior images were obtained at 72 h after administration of 3 mCi ⁶⁷Ga-citrate using a gamma camera (Maxi-Camera 400T, General Electric Co.) with a medium energy standard parallel hole collimator. Abnormally high accumulations were observed in 17 out of 25 cases (superficial lymph node, 8; hilar and mediastinal lymph node, 7; paraaortic lymph node, 2; lung, 9; liver, 1; bone, 1). There were 10 malignant lesions detected by ⁶⁷Ga scintigraphy in 9 out of 17 cases (superficial lymph node, 1; hilar and mediastinal lymph node, 6; paraaortic lymph node, 1; liver, 1; bone, 1). White blood cell count and serum LDH levels were raised in patients with abnormally high accumulations of ⁶⁷Ga. In conclusion, ⁶⁷Ga scintigraphy seemed to be a useful examination to detect malignant lesions in patients with ATLL.     

Experimental and clinical studies on differential diagnosis of bone diseases with nucleomedical procedures

This report is a study of the differential diagnosis of bone diseases using nucleomedical procedures. Experimental and clinical studies on the accumulation of ²⁰¹Tl and ⁶⁷Ga in bone inflammation and bone tumors were performed. Also, the degree of deposition of ^99mTc-phosphorous compounds represented as a color difference was evaluated for a differentiation between malignant and benign diseases of the spine and shoulder. Uptake of ²⁰¹Tl in inflammation of the spine and in tumor of the pelvis of rabbits was very low, while that of ⁶⁷Ga was high. Uptake of ⁶⁷Ga decreased gradually with lapse of time after the onset of inflammation. These experimental results agreed with clinical studies. The detectability of malignant tumors with ²⁰¹Tl was inferior to that with ^99mTc-label and ⁶⁷Ga, although osteolytic lesions were occasionally ²⁰¹Tl-positive. In terms of color range, the difference was 2 or less in spines of normal subjects and 3 or more in the metastatic bone disease and compression fracture. This difference was not statistically significant. Since ⁶⁷Ga scan was occasionally negative in compression fracture, a differentiation was considered to be possible in such a case. A combined study of bone imaging with ^99mTc-phosphorous compound including color difference, ⁶⁷Ga imaging, bone-marrow imaging and radiography are considered to be helpful for the differentiation.     

<Superscript>68</Superscript>Ga-PSMA 11 ligand PET imaging in patients with biochemical recurrence after radical prostatectomy – diagnostic performance and impact on therapeutic decision-making

Objective

To evaluate the diagnostic performance of [⁶⁸Ga]Ga-PSMA^HBED-CC conjugate 11 positron emission tomography (PSMA-PET) in the early detection of metastases in patients with biochemical recurrence (BCR) after radical prostatectomy (RP) for clinically non-metastatic prostate cancer, to compare it to CT/MRI alone and to assess its impact on further therapeutic decisions.

Material and methods

We retrospectively assessed 117 consecutive hormone-naïve BCR patients who had ⁶⁸Ga-PSMA 11 PET/CT (n = 46) or PET/MRI (n = 71) between May 2014 and January 2017. BCR was defined as two PSA rises above 0.2 ng/ml. Two dedicated uro-oncological imaging experts (radiology/nuclear medicine) reviewed separately all images. All results were presented in a blinded sequential fashion to a multidisciplinary tumorboard in order to assess the influence of PSMA-PET imaging on decision-making.

Results

The median time from RP to BCR was 36 months (IQR 16–72). Overall, 69 (59%) patients received postoperative radiotherapy. Median PSA level at the time of imaging was 1.04 ng/ml (IQR 0.58–1.87). PSMA-positive lesions were detected in 100 (85.5%) patients. Detection rates were 65% for a PSA value of 0.2 to <0.5 ng/ml, 85.7% for 0.5 to <1, 85.7% for 1 to <2 and 100% for ≥2. PSMA-positive lesions could be confirmed by either histology (16%), PSA decrease in metastasis-directed radiotherapy (45%) or additional information in diffusion-weighted imaging when PET/MRI was performed (18%) in 79% of patients. PSMA-PET detected lesions in 67 patients (57.3%) who had no suspicious correlates according to the RECIST 1.1 criteria on MRI or CT. PSMA-PET changed therapeutic decisions in 74.6% of these 67 patients (p < 0.001), with 86% of them being considered for metastases-directed therapies.

Conclusions

We confirm the high performance of PSMA-PET imaging for the detection of disease recurrence sites in patients with BCR after RP, even at relatively low PSA levels. Moreover, it adds significant information to standard CT/MRI, changing treatment strategies in a significant number of patients.