Shuren Li

Vasoactive Intestinal Peptide-Receptor Imaging for the Localization of Intestinal Adenocarcinomas and Endocrine Tumors

Background Intestinal adenocarcinomas and various endocrine tumors express large numbers of high-affinity receptors for vasoactive intestinal peptide (VIP). We have evaluated the usefulness of scanning with VIP labeled with iodine-123 for tumor localization in patients with gastrointestinal tumors. Methods Radioiodinated VIP was purified by high-pressure liquid chromatography and administered as a single intravenous bolus injection (300 pmol [1 microgram]). Scanning with radiolabeled VIP was compared with computed tomography and scanning with somatostatin analogues in 79 patients with colorectal cancer, pancreatic carcinoma, gastric cancer, carcinoid tumor, or insulinoma. Results Visualization of gastrointestinal tumors and metastases was obtained with radiolabeled VIP. Binding of the labeled peptide by primary tumors and metastases was visible shortly after the injection and was still demonstrable at 24 hours. In patients with colorectal adenocarcinomas, primary or recurrent tumors were visualized in 10 ...

11C-Acetate Positron Emission Tomography Imaging and Image Fusion With Computed Tomography and Magnetic Resonance Imaging in Patients With Recurrent Prostate Cancer

PURPOSE To assess the clinical value of computed tomography (CT) and magnetic resonance imaging (MRI) image fusion with 11C-acetate (AC) positron emission tomography (PET) imaging for detection and exact location of clinically occult recurrences. PATIENTS AND METHODS Fifty prostate cancer patients with elevated/increasing serum prostate-specific antigen levels after radical therapy underwent whole-body AC PET. Uptake was initially interpreted as normal, abnormal, or equivocal. In case of abnormal or equivocal uptake, additional conventional imaging techniques, such as CT, MRI, and bone scans, were performed. To precisely define the anatomic location of abnormal uptake and to improve characterization of equivocal lesions, a software-assisted image fusion (CT-PET, MRI-PET) was performed and evaluated as site-by-site analysis of 51 abnormal (n = 37) or equivocal (n = 14) sites of all 50 patients. In 17 patients, additional histopathologic evaluation was available. RESULTS In five (10%), 13 (26%), and 32 (64%) of the 50 patients, AC PET studies demonstrated AC uptake judged as normal, equivocal, and abnormal, respectively. Image fusion changed characterization of equivocal lesions as normal in five (10%) of 51 sites and abnormal in nine (18%) of 51 sites. It precisely defined the anatomic location of abnormal uptake in 37 (73%) of 51 sites. AC PET findings did influence patient management in 14 (28%) of 50 patients. CONCLUSION Retrospective fusion of AC PET and CT/MRI is feasible and seems to be essential for final diagnosis. This is particularly true in patients with AC uptake in the prostate region.

Characterization of 123I-vascular endothelial growth factor–binding sites expressed on human tumour cells: Possible implication for tumour scintigraphy

To explore the possibility of vascular endothelial growth factor (VEGF) receptor scintigraphy of primary tumours and their metastases, we analysed the binding properties of 123I‐labelled VEGF165 (123I‐VEGF165) and 123I‐VEGF121 to human umbilical vein endothelial cells (HUVECs), several human tumour cell lines (HMC‐1, A431, KU812, U937, HEP‐1, HEP‐G2, HEP‐3B and Raji), a variety of primary human tumours (n = 40) and some adjacent non‐neoplastic tissues as well as normal human peripheral blood cells in vitro. Two classes of high‐affinity 123I‐VEGF165‐binding site were found on the cell surface of HUVECs. In contrast, one class of high‐affinity binding sites for 123I‐VEGF165 was found on HMC‐1, A431, HEP‐1, HEP‐G2, HEP‐3B and U937 cells as well as many primary tumours. For 123I‐VEGF121, a single class of high‐affinity binding site was found on certain cell lines (HUVEC, HEP‐1 and HMC‐1) and distinct primary tumours (primary melanomas, ductal breast cancers and ovarian carcinomas as well as meningiomas). Tumour cells expressed significantly higher numbers of VEGF receptors compared with normal peripheral blood cells and adjacent non‐neoplastic tissues. Immunohistochemical staining revealed that the VEGF receptor Flk‐1 is expressed to a much higher extent within malignant tissues compared with neighbouring non‐neoplastic cells. We observed significantly greater specific binding of 123I‐VEGF165 and 123I‐VEGF121 to a variety of human tumour cells/tissues compared with the corresponding normal tissues or normal peripheral blood cells. In comparison with 123I‐VEGF121, 123I‐VEGF165 bound to a higher number of different tumour cell types with a higher capacity. Thus, 123I‐VEGF165 may be a potentially useful tracer for in vivo imaging of solid tumours.

123I-vasoactive intestinal peptide (VIP) receptor scanning: Update of imaging results in patients with adenocarcinomas and endocrine tumors of the gastrointestinal tract

Recent data suggest that functional receptors (R) for vasoactive intestinal peptide (VIP) are expressed on various tumor cells. The high-level expression of VIPR on tumor cells provided the basis for the successful use of 123I-labeled VIP for the in vivo localization of intestinal adenocarcinomas and endocrine tumors. We here report an update of our imaging results using 123I-VIP (150-200 MBg/1 microgram/patient) in 169 patients. In patients with pancreatic adenocarcinomas without liver metastases, the primary/recurrent tumor was visualized in 16 of 18 patients (89%) and liver metastases were imaged in 15 of 16 patients. In 11 of 12 patients with colorectal adenocarcinomas, the primary/recurrent tumor (92%) was imaged by 123I-VIP. Also, in 21 of 25 patients, liver metastases (84%); in 3 of 6 patients, lung metastases (50%); and in 4 of 5 patients, lymph-node metastases (80%) were imaged by 123I-VIP. In 10 of 10 patients with gastric adenocarcinomas, the primary/recurrent tumor; in 3 of 4 patients, liver metastases; and in 2 of 2 patients, lymph-node metastases were visualized by 123I-VIP. 123I-VIP localized primary intestinal carcinoid tumors in 15 of 17 patients (88%) and 8 of 10 primary insulinomas (80%). We conclude that the 123I-VIPR scintigraphy localizes intestinal adenocarcinomas and endocrine tumors as well as metastatic tumor sites.

The radionuclide molecular imaging and therapy of neuroendocrine tumors.

Neuroendocrine tumors (NETs) represent a large group of neoplasms deriving from pluripotent stem cells or from differentiated neuroendocrine cells that are characterized by the expression of different peptides and biogenic amines. These rare tumors tend to grow slowly and are notoriously difficult to localize, at least in the early stages. Diagnostics involve blood, urine and biochemical examination as well as imaging modalities. Imaging is achieved by a variety of techniques such as radiological morphological imaging methods, for example, sonography, computerized tomography (CT)/magnetic resonance imaging (MRI), angiography and finally, nuclear functional imaging methods such as metaiodobenzylguanidine (MIBG), somatostatin receptor scintigraphy (SRS), vasoactive intestinal peptide receptor scintigraphy (VIPRS) and positron emission tomography (PET) using (18)F labeled deoxyglucose (FDG) and fluorinated dihydroxyphenylalanine ((18)F-DOPA) as a radioisotopic marker. (131)I-labeled MIBG is a well-established radiopharmaceutical for localization and therapy of phechromocytoma and paraganglioma. The majority of neuroendocrine tumors possess a high density of somatostatin receptors. This observation provided the basis for the development of various radiolabeled somatostatin peptide analogs as imaging agents and therapeutics in nuclear medicine. FDG-PET is now performed in a wide variety of tumors and indications, including diagnosis, staging, re-staging and evaluation of the response to treatment. (18)F-DOPA-PET may be useful if (18)F-FDG-PET scan result is negative. (99m)Tc-pentavalent dimercaptosuccinic acid ((99m)Tc-DMSA-V) or (99m)Tc sestamibi ((99m)Tc-MIBI) or (99m)Tc-tetrofosmin is used only for diagnosis of certain NETs such as medullary thyroid cancer. The expiences with other nuclear medicinie imaging and therapy modalities such as cholecystokinin (CCK)-B/gastrin-receptors, bombesin/gastrin-releasing peptide receptor scintigraphy are still limited, and further clinical studies are needed. The studies using vascular endothelial growth factor (VEGF) for tumor angiogenesis imaging, annexin-V for imaging apoptosis and agents for hypoxia imaging are still in an early stage and the clinical role for these agents needs to be defined. In conclusion, no single imaging technique identifies all the metastatic sites of NETs. The best results may be obtained with a combination of functional imaging such as PET or/and SRS and morphologic imaging with CT and/or MR imaging. Many molecular imaging and therapy modalities fur NETs are recently under investigation or being developed, the usefulness of these modalities, however, has to be evaluated by well-designed and multicentre studies.

Comparison of 111In-DOTA-DPhe1-Tyr3-octreotide and 111In-DOTA-lanreotide scintigraphy and dosimetry in patients with neuroendocrine tumours

PurposeSomatostatin receptor scintigraphy with 111In-DOTA-DPhe1-Tyr3-octreotide (111In-DOTA-TOC) and 111In-DOTA-lanreotide (111In-DOTA-LAN) has been used for staging of neuroendocrine tumours (NETs). However, the comparative diagnostic value of these radioligands on a lesion basis has not yet been established. The aim of this study was to compare the diagnostic capacity of 111In-DOTA-TOC and 111In-DOTA-LAN scintigraphy in patients with NETs, evaluating whether significant differences exist in lesion imaging with these radioligands. Furthermore, dosimetric data were compared.MethodsForty-five patients with NETs were investigated with 111In-DOTA-TOC and 111In-DOTA-LAN scintigraphy. Scintigraphic results were compared with those of conventional imaging and/or surgery in each patient, and also 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in 20 patients.Results111In-DOTA-TOC and 111In-DOTA-LAN scintigraphy were true positive in 42/45 (93%) and 39/45 (87%) patients, and imaged 74/91 (81%) and 73/91 (80%) tumour lesions, respectively. 111In-DOTA-TOC and 111In-DOTA-LAN detected liver metastases in 21 and 14 patients, mediastinal metastases in seven and 11 patients, and bone metastases in two and seven patients, respectively. These radioligands revealed lesions not seen by conventional imaging in seven and eight patients, respectively, or by 18F-FDG-PET in eight and seven patients, respectively. The estimated tumour absorbed doses for 90Y-DOTA-TOC were higher than those for 90Y-DOTA-LAN in 14 patients, whereas the opposite was true in 12 patients.ConclusionBoth 111In-DOTA-TOC and 111In-DOTA-LAN are suitable for imaging tumour lesions in patients with NETs and can detect lesions that may not be seen by conventional imaging and 18F-FDG-PET. Compared with 111In-DOTA-LAN, 111In-DOTA-TOC has a superior diagnostic capacity for liver metastases, but a lower diagnostic capacity for metastatic lesions in mediastinum and bone.

In vitro and in vivo studies of three radiolabelled somatostatin analogues:123I-Octreotide (OCT),123I-Tyr-3-OCT and111In-TIRA-d-Phe-1-OCT

Scintigraphy with long-acting somatostatin (SST) analogues may be useful for the localization of tumours expressing receptors (R) for SST. In this study we have analysed the in vitro and in vivo binding properties of three SST analogues,123I-octreotide (OCT),123I-Tyr-3-OCT and111In-DTPA-d-Phe-l-OCT. In vitro binding studies performed with a variety of primary tumours (n=48) as well as with several tumour cell lines (A431, HT29, PANC1, COLO320, HMC1, KU812) indicated significant in vitro binding of these three radiolabelled SST analogues to two subpopulations of SSTR, high (Kd 0.2–2.0 nM) and low (Kd 5–15 nM) affinity ones. The number of SSTR on tumour cells was at least a 1000-fold higher as compared with normal peripheral blood cells. Comparative scintigraphic studies using123I-OCT and/or123I-Tyr-3-OCT and/or111In-DTPA-d-Phe-1-OCT were performed in 21 patients with histologically verified intestinal carcinoid tumours. Corresponding scintigraphic results were obtained in 18 of 21 patients investigated with two different SSTR ligands, either123I-OCT/123I-Tyr-3-OCT (four of five),123I-OCT/111In-DTPA-d-Phe-1-OCT (eight of nine), or123I-Tyr-3-OCT/111In-DTPA-d-Phe-1-OCT (six of seven). We conclude that various tumours express high amounts of SSTR which are recognized by three radiolabelled SST analogues:123I-OCT,123I-Tyr-3-OCT and111In-DTPA-d-Phe-1-OCT. Differences between these SST analogues in their in vitro binding and/or in vivo scanning properties are observed in a minority of patients. Thus, the labelling of OCT with iodine may be an alternative approach for those nuclear medicine departments for which111In-DTPA-d-Phe-1-OCT is not easily available, or is too expensive.

Hepatocellular Carcinoma: A Phase II Randomized Controlled Double-Blind Trial of Transarterial Chemoembolization in Combination with Biweekly Intravenous Administration of Bevacizumab or a Placebo

PURPOSE To investigate the efficacy and safety of conventional transarterial chemoembolization (TACE) (cTACE) in combination with bevacizumab or a placebo in patients with hepatocellular carcinoma (HCC) in a randomized controlled double-blind phase II trial. MATERIALS AND METHODS This study was approved by the institutional review board, and written informed consent was obtained prior to inclusion. A total of 40 patients (20 patients per group, all 18 years or older) with histologically confirmed early- or intermediate-stage HCC and Child-Pugh class A or B cirrhosis were scheduled for inclusion. The primary endpoint was radiologic progression at 12 months according to European Association for the Study of the Liver criteria. Secondary endpoints were safety and overall survival (OS). Patients underwent cTACE with doxorubicin and intravenous administration of a placebo (cTACE-C) or bevacizumab (cTACE-B) (5 mg per kilogram of body weight) every 2 weeks for 52 weeks. After the first TACE procedure, TACE was repeated twice in 4-week intervals if indicated and technically feasible and on demand thereafter. Statistical analyses were performed with statistical software. P < .05 indicated a significant difference. RESULTS Thirty-two patients were recruited between January 2006 and December 2009 (29 male, three female; mean age, 61 years ± 8 [standard deviation]; Barcelona Clinic Liver Cancer stage A, n = 4; Barcelona Clinic Liver Cancer stage B, n = 28; predominant cause, alcohol [n = 15]; Child-Pugh class A disease, n = 22; Child-Pugh class B disease, n = 10; 16 patients received bevacizumab; 16 patients received a placebo). Patients underwent a median of three TACE cycles and received 13 infusions of bevacizumab versus 11 infusions of the placebo before the trial was stopped prematurely for safety reasons. Severe (grade 3-5) septic (n = 8 vs n = 3) and vascular (n = 9 vs n = 0) side effects were observed almost exclusively in the cTACE-B group. Median survival was worse in the cTACE-B group than in the cTACE-C group (5.3 vs 13.7 months; hazard ratio [HR], 1.7; 95% confidence interval [CI]: 0.8, 3.6; P = .195) and reached significance in patients with Child-Pugh class A cirrhosis (7.3 vs 26.5 months; HR, 2.6; 95% CI: 1.0, 6.6; P = .049). The primary endpoint was not met, since there was no difference in radiologic response between the groups at 3, 6, or 12 months. CONCLUSION No improvement in radiologic tumor response or OS was observed in patients with HCC who received cTACE and bevacizumab, but severe and even lethal septic and vascular side effects occurred. Thus, bevacizumab cannot be recommended as an adjuvant treatment to cTACE.

Value of 111In-DOTA-lanreotide and 111In-DOTA-DPhe1-Tyr3-octreotide in differentiated thyroid cancer: results of in vitro binding studies and in vivo comparison with 18F-FDG PET

PurposeRadioiodine-negative thyroid cancer presents diagnostic and therapeutic difficulties, warranting the implementation of new imaging and treatment strategies. The purpose of this study was twofold. First, we investigated in vitro the binding characteristics of 111In-DOTA-lanreotide (111In-DOTA-LAN) and 111In-DOTA-DPhe1-Tyr3-octreotide (111In-DOTA-TOC) to cells derived from differentiated thyroid cancer (DTC). Second, we evaluated the value of somatostatin receptor (SSTR) scintigraphy with these radioligands, as compared with 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET), for the detection of tumour lesions in DTC patients.Methods Binding of 111In-DOTA-LAN and 111In-DOTA-TOC to cells isolated from surgically removed thyroid tissue was evaluated in vitro by performing saturation and displacement studies. Eighteen DTC patients with elevated thyroglobulin (12 radioiodine-negative, six radioiodine-positive) were investigated with 111In-DOTA-LAN, 111In-DOTA-TOC and 18F-FDG PET scans.ResultsLarge numbers of SSTR binding sites for 111In-DOTA-LAN and 111In-DOTA-TOC were found on the cells investigated. Both SSTR radioligands exhibited a high binding affinity for these SSTR binding sites. 111In-DOTA-LAN and 111In-DOTA-TOC scintigraphy detected 37 and 33 lesions, respectively, in 17 (94%) patients each, whereas 18F-FDG PET revealed 30 lesions in 15 (83%) patients. Uptake of both SSTR radioligands was found in several radioiodine-negative sites. No striking differences in lesion imaging by 111In-DOTA-LAN and 111In-DOTA-TOC were found. In both radioiodine-negative and radioiodine-positive patients, more lesions were SSTR-positive/18F-FDG-negative than were 18F-FDG-positive/SSTR-negative.ConclusionAdding a SSTR scan with these radioligands to the diagnostic work-up increases the diagnostic capacity in DTC, and should be considered particularly in radioiodine-negative patients with elevated thyroglobulin levels.

Comparison of 11C-acetate positron emission tomography and 67Gallium citrate scintigraphy in patients with hepatocellular carcinoma

Abstract: Aims: Nuclear imaging may have an increasing role in the diagnosis of hepatocellular carcinoma (HCC). The aim of this study was to compare prospectively the Gallium‐67 citrate (67Ga) scintigraphy results with those obtained by positron emission tomography (PET) using 11C‐acetate in patients with HCC.