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Wim J G Oyen

Publications and source records attributed to Wim J G Oyen.

At least 19 recordsLinked to original sources
PubMed2007

Alpha v beta 3 integrin-targeting of intraperitoneally growing tumors with a radiolabeled RGD peptide.

Ovarian cancer is the fourth most common cause of cancer deaths among females in the western world after cancer of the breast, colon and lung. The inability to control the disease within the peritoneal cavity is the major cause of treatment failure in patients with ovarian cancer. The majority of ovarian carcinomas express the alpha(v)beta(3) integrin. Here we studied the tumor targeting potential of an (111)In-labeled cyclic RGD peptide in athymic BALB/c mice with intraperitoneally (i.p.) growing NIH:OVCAR-3 human ovarian carcinoma tumors. The cyclic RGD peptide, c(RGDfK)E, was synthesized, conjugated with DOTA and radiolabeled with (111)In. The targeting potential of (111)In-DOTA-E-c(RGDfK) was studied in athymic mice with i.p. growing NIH:OVCAR-3 xenografts and the optimal dose of this compound was determined (0.01 microg up to 10 microg). The biodistribution at optimal peptide dose was determined at various time points (0.5 up to 72 hr). Furthermore, the therapeutic potential of (177)Lu-DOTA-E-c(RGDfK) was studied in this model. Two hours after i.p. administration, (111)In-DOTA-E-c(RGDfK) showed high and specific uptake in the i.p. growing tumors. Optimal uptake in the i.p. growing tumors was observed at a 0.03-0.1 microg dose range. Tumor uptake of (111)In-DOTA-E-c(RGDfK) peaked 4 hr p.i. [(38.8 +/- 2.7)% ID/g], gradually decreasing at later time points [(24.0 +/- 4.1)% ID/g at 48 hr p.i.]. Intraperitoneal growth of OVCAR-3 could be significantly delayed by injecting 37 MBq (177)Lu-labeled peptide i.p. Radiolabeled DOTA-E-c(RGDfK) is suitable for targeting of i.p. growing tumors and potentially can be used for peptide receptor radionuclide therapy of these tumors.

Animals↗
PubMed2007

Effects of linker variation on the in vitro and in vivo characteristics of an 111In-labeled RGD peptide.

INTRODUCTION: Due to the selective expression of the alpha(v)beta3 integrin in tumors, radiolabeled arginine-glycine-aspartic acid (RGD) peptides are attractive candidates for tumor targeting. Minor modifications of these peptides could have a major impact on in vivo characteristics. In this study, we systematically investigated the effects of linker modification between two cyclic RGD sequences and DOTA (1,4,7,10-tetraazadodecane-N,N',N",N'''-tetraacetic acid) on the in vitro and in vivo characteristics of the tracer. METHODS: A dimeric RGD peptide was synthesized and conjugated either directly with DOTA or via different linkers: PEG4 (polyethylene glycol), glutamic acid or lysine. The RGD peptides were radiolabeled with 111In, and their in vitro and in vivo alpha(v)beta3-binding characteristics were determined. RESULTS: LogP values varied between -2.82+/-0.06 and -3.95+/-0.33. The IC50 values for DOTA-E-[c(RGDfK)]2, DOTA-PEG4-E-[c(RGDfK)]2, DOTA-E-E-[c(RGDfK)]2 and DOTA-K-E-[c(RGDfK)]2 were comparable. Two hours after injection, the tumor uptakes of the 111In-labeled compounds were not significantly different. The kidney accumulation of [111In]-DOTA-K-E-[c(RGDfK)]2 [4.05+/-0.20% of the injected dose per gram (ID/g)] was significantly higher as compared with that of [111In]-DOTA-E-[c(RGDfK)]2 (2.63+/-0.19% ID/g; P<.05) as well as that of [111In]-DOTA-E-E-[c(RGDfK)]2 (2.16+/-0.21% ID/g; P<.01). The liver uptake of [111In]-DOTA-E-E-[c(RGDfK)]2 (2.12+/-0.09% ID/g) was significantly higher as compared with that of [111In]-DOTA-E-[c(RGDfK)]2 (1.64+/-0.1% ID/g; P<.05) as well as that of [111In]-DOTA-K-E-[c(RGDfK)]2 (1.52+/-0.04% ID/g; P<.01). CONCLUSIONS: Linker variation did not affect affinity for alpha(v)beta3 and tumor uptake. Insertion of lysine caused enhanced kidney retention; that of glutamic acid also resulted in enhanced retention in the kidneys. PEG4 appeared to be the most suitable linker as compared with glutamic acid and lysine because it has the highest tumor-to-blood ratio and the lowest uptake in the kidney and liver.

Animals↗
PubMed2007

A prospective multicenter study on fever of unknown origin: the yield of a structured diagnostic protocol.

We conducted a prospective study to update our knowledge of fever of unknown origin (FUO) and to explore the utility of a structured diagnostic protocol. From December 2003 to July 2005, 73 patients with FUO were recruited from 1 university hospital (n = 40) and 5 community hospitals (n = 33) in the same region in The Netherlands. FUO was defined as a febrile illness of >3 weeks' duration, a temperature of >38.3 degrees C on several occasions, without a diagnosis after standardized history-taking, physical examination, and certain obligatory investigations. Immunocompromised patients were excluded. A structured diagnostic protocol was used. Patients from the university hospital were characterized by more secondary referrals and a higher percentage of periodic fever than those referred to community hospitals. Infection was the cause in 16%, a neoplasm in 7%, noninfectious inflammatory diseases in 22%, miscellaneous causes in 4%, and in 51%, the cause of fever was not found (no differences between university and community hospitals). There were no differences regarding the number and type of investigations between university and community hospitals. Significant predictors for reaching a diagnosis included continuous fever; fever present for <180 days; elevated erythrocyte sedimentation rate, C-reactive protein, or lactate dehydrogenase; leukopenia; thrombocytosis; abnormal chest computed tomography (CT); and abnormal F-fluorodeoxyglucose positron emission tomography (FDG-PET). For future FUO studies, inclusion of outpatients and the use of a set of obligated investigations instead of a time-related criterion are recommended. Except for tests from the obligatory part of our protocol and cryoglobulins in an early stage, followed by FDG-PET, and in a later stage by abdominal and chest CT, temporal artery biopsy in patients aged 55 years or older, and possibly bone marrow biopsy, other tests should not be used as screening investigations.

Adult↗
PubMed2006

Comparison between local ablative therapy and chemotherapy for non-resectable colorectal liver metastases: a prospective study.

BACKGROUND: There is a growing interest for the use of local ablative techniques in patients with non-resectable colorectal liver metastases. Evidence on the efficacy over systemic chemotherapy is, however, extremely weak. In this prospective study we aim to assess the additional benefits of local tumour ablation. METHODS: A consecutive series of 201 colorectal cancer patients, without extrahepatic disease, that underwent laparotomy for surgical treatment of liver metastases, were prospectively followed for survival and HRQoL. At laparotomy three groups were identified: patients in whom radical resection of metastases proved feasible, patients in whom resection was not feasible and received local ablative therapy, and patients in whom resection or local ablation was not feasible for technical reasons and who received systemic chemotherapy. FINDINGS: Patients in the chemotherapy and in local ablation group were comparable for all prognostic variables tested. For the local ablation group overall survival at 2 and 5 years was 56 and 27%, respectively (median 31 months, n = 45), for the chemotherapy group 51 and 15%, respectively (median 26 months, n = 39) (P = 0.252). After resection these figures were 83 and 51%, respectively (median 61 months, n = 117) (P < 0.001). The median DFS after local ablation was 9 months, HRQoL was restored within 3 months. Patients after local ablation gained far more QALY's (317) than in the chemotherapy group (165) (P < 0.001). INTERPRETATION: Although overall survival did not reached statistical significance, the median DFS of 9 months suggests a beneficial effect of local tumour ablation for non-resectable colorectal liver metastases. Moreover, compared with systemic chemotherapy more QALY's were gained after local ablative therapy.

Adult↗
PubMed2006

A prospective multi-centre study of the value of FDG-PET as part of a structured diagnostic protocol in patients with fever of unknown origin.

PURPOSE: Since (18)F-fluorodeoxyglucose (FDG) accumulates in neoplastic cells and in activated inflammatory cells, positron emission tomography (PET) with FDG could be valuable in diagnosing patients with fever of unknown origin (FUO). The aim of this study was to validate the use of FDG-PET as part of a structured diagnostic protocol in the general patient population with FUO. METHODS: From December 2003 to July 2005, 70 patients with FUO were recruited from one university hospital (n=38) and five community hospitals (n=32). A structured diagnostic protocol including FDG-PET was used. A dedicated, full-ring PET scanner was used for data acquisition. FDG-PET scans were interpreted by two staff members of the department of nuclear medicine without further clinical information. The final clinical diagnosis was used for comparison with the FDG-PET results. RESULTS: Of all scans, 33% were clinically helpful. The contribution of FDG-PET to the final diagnosis did not differ significantly between patients diagnosed in the university hospital and patients diagnosed in the community hospitals. FDG-PET contributed significantly more often to the final diagnosis in patients with continuous fever than in patients with periodic fever. FDG-PET was not helpful in any of the patients with normal erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). CONCLUSION: FDG-PET is a valuable imaging technique as part of a diagnostic protocol in the general patient population with FUO and a raised ESR or CRP.

Adult↗
PubMed2006

Timing of adjuvant radioimmunotherapy after cytoreductive surgery in experimental peritoneal carcinomatosis of colorectal origin.

BACKGROUND: Treatment of patients with peritoneal carcinomatosis (PC) of colorectal cancer (CRC) includes cytoreductive surgery (CS) in combination with (hyperthermic) intraperitoneal chemotherapy (HIPEC), resulting in a limited survival benefit with high morbidity and mortality rates. Radioimmunotherapy (RIT) as adjuvant therapy after CS of CRC has been shown to prolong survival in preclinical studies. However, the optimal setting of RIT remains to be determined. METHODS: PC was induced by intraperitoneal inoculation of CC-531 colon carcinoma cells in Wag/Rij rats. Animals were subjected to exploratory laparotomy (Sham), CS only or CS + RIT at different time points after surgery. RIT consisted of 55 MBq lutetium-177-labelled anti-CC531 antibody MG1 (183 mug). The primary endpoint was survival. RESULTS: Cytoreductive surgery with or without RIT was well tolerated. Median survival of animals in the Sham and CS group was 29 days and 39 days, respectively (P < 0.04). Compared to CS alone, median survival of rats after adjuvant RIT was 77 days (P < 0.0001), 52 days (P < 0.0001) and 45 days (P < 0.0001) when given directly, 4 and 14 days after surgery, respectively. CONCLUSION: The efficacy of adjuvant RIT after CS for the treatment of PC of colonic origin decreases when the administration of the radiolabelled MAbs is postponed. This study shows that adjuvant RIT should be given as early as possible after surgery.

Animals↗
PubMed2006

Gender differences in Parkinson's disease.

OBJECTIVE: To investigate gender differences in basic disease characteristics, motor deterioration and nigrostriatal degeneration in Parkinson's disease (PD). METHODS: We studied 253 consecutive PD patients who were not receiving levodopa or dopamine agonists (disease duration < or = 10 years). We investigated the influence of gender and oestrogen status on: (1) age at onset, (2) presenting symptom, (3) severity and progression of motor symptoms (Unified Parkinson's Disease Rating Scale III (UPDRS-III) scores) and (4) amount and progression of nigrostriatal degeneration ([123I]FP-CIT single photon emission computed tomography measurements). RESULTS: Age at onset was 2.1 years later in women (53.4 years) than in men (51.3 years). In women, age at onset correlated positively with parity, age at menopause and fertile life span. Women more often presented with tremor (67%) than men (48%). Overall, patients presenting with tremor had a 3.6 year higher age at onset and a 38% slower UPDRS-III deterioration. Mean UPDRS-III scores at disease onset were equal for both genders, as was the rate of deterioration. Women had a 16% higher striatal [123I]FP-CIT binding than men at symptom onset and throughout the course of PD. CONCLUSIONS: Our results suggest that, in women, the development of symptomatic PD may be delayed by higher physiological striatal dopamine levels, possibly due to the activity of oestrogens. This could explain the epidemiological observations of a lower incidence and higher age at onset in women. Women also presented more often with tremor which, in turn, is associated with milder motor deterioration and striatal degeneration. Taken together, these findings suggest a more benign phenotype in women with PD.

Adult↗
PubMed2006

FDG-PET in colorectal cancer.

[18F]Fluorodeoxyglucose (FDG) positron emission tomography (PET) is a useful imaging tool in the evolving management of patients with colorectal carcinoma. This technique is able to measure and visualize metabolic changes in cancer cells. This feature results in the ability to distinguish viable tumor from scar tissue, in the detection of tumor foci at an earlier stage than possible by conventional anatomic imaging and in the measurement of alterations in tumor metabolism, indicative of tumor response to therapy. Nowadays, FDG-PET plays a pivotal role in staging patients before surgical resection of recurrence and metastases, in the localization of recurrence in patients with an unexplained rise in serum carcinoembryonic antigen and in assessment of residual masses after treatment. In the presurgical evaluation, FDG-PET may be best used in conjunction with anatomic imaging in order to combine the benefits of both anatomical (CT) and functional (PET) information, which leads to significant improvements in preoperative liver staging and preoperative judgment on the feasibility of resection. Integration of FDG-PET into the management algorithm of these categories of patients alters and improves therapeutic management, reduces morbidity due to futile surgery, leads to substantial cost savings and probably also to a better patient outcome. FDG-PET also appears to have great potential in monitoring the success of local ablative therapies soon after intervention and in the prediction and evaluation of response to radiotherapy, systemic therapy, and combinations thereof. This review aims to outline the current and future role of FDG-PET in the field of colorectal cancer.

Adenocarcinoma↗
PubMed2006

Nuclear medicine imaging and therapy of neuroendocrine tumours.

Radiolabelled peptides are used for specific targeting of receptors (over-)expressed by tumour cells. Dependent on the kind of labelling and the radionuclide used, these compounds may be utilised for imaging or for therapy. A concise overview is provided on basic principles of designing and developing radiopeptides for these applications. Furthermore, clinical application of these compounds for imaging and therapy is described. Advantages of the method compared to other techniques (such as the use of radiolabelled antibodies or antibody fragments) are discussed as well as pitfalls and limitations.

Bone Marrow Diseases↗
PubMed2006

Biological correlates of FDG uptake in non-small cell lung cancer.

PURPOSE: Each pathological stage of non-small cell lung cancer (NSCLC) consists of a heterogeneous population containing patients at much higher risk than others. Noninvasive functional imaging modalities, such as 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), could play a role in further characterization of NSCLCs. As many factors can influence the extent of FDG uptake, the underlying mechanisms for FDG accumulation in tumors, are still a matter of debate. The aim of the present study was to investigate these possible mechanisms in the primary site of early stage preoperatively untreated NSCLC. METHODS: 19 patients with early stage NSCLC, who had undergone both preoperative FDG-PET imaging and curative surgery, were enrolled in this study. Standardized uptake values (SUVs) were used for evaluation of primary tumor FDG uptake. Final diagnosis, tumor type, tumor cell differentiation and size of the primary tumors were confirmed histopathologically in resected specimens. Histologic sections were analyzed for amount of inflammation and necrosis. Expression of the glucose membrane transporters (GLUT-1 and GLUT-3); the isoforms of the glycolytic enzyme hexokinase (HK-I, HK-II and HK-III); and the cysteine protease caspase-3, was evaluated immunohistochemically. RESULTS: FDG uptake was significantly higher in squamous cell carcinomas (mean SUV 13.4+/-4.9, n=8) compared to adenocarcinomas (7.1+/-3.3, n=8, p=0.007), or large cell carcinomas (5.9+/-1.9, n=3, p=0.02). The degree of FDG accumulation seemed to depend especially on GLUT-1, GLUT-3 and tumor cell differentiation. The summed standardized values of these three parameters correlated significantly with the SUV (r=0.47, p=0.05). CONCLUSION: The present study supports the hypothesis that tumor cell differentiation in combination with overexpression of GLUT-1 and GLUT-3 determine the extent of FDG accumulation and that squamous cell carcinomas accumulate more FDG than adenocarcinomas or large cell carcinomas.

Adult↗
PubMed2006

Improved targeting of the alpha(v)beta (3) integrin by multimerisation of RGD peptides.

PURPOSE: The integrin alpha(v)beta(3) is expressed on sprouting endothelial cells and on various tumour cell types. Due to the restricted expression of alpha(v)beta(3) in tumours, alpha(v)beta(3) is considered a suitable receptor for tumour targeting. In this study the alpha(v)beta(3) binding characteristics of an (111)In-labelled monomeric, dimeric and tetrameric RGD analogue were compared. METHODS: A monomeric (E-c(RGDfK)), dimeric (E-[c(RGDfK)](2)), and tetrameric (E{E[c(RGDfK)](2)}(2)) RGD peptide were synthesised, conjugated with DOTA and radiolabelled with (111)In. In vitro alpha(v)beta(3) binding characteristics were determined in a competitive binding assay. In vivo alpha(v)beta(3) targeting characteristics of the compounds were assessed in mice with SK-RC-52 xenografts. RESULTS: The IC(50) values for DOTA-E-c(RGDfK), DOTA-E-[c(RGDfK)](2), and DOTA-E{E[c(RGDfK)](2)}(2)were 120 nM, 69.9 nM and 19.6 nM, respectively. At all time points, the tumour uptake of the dimer was significantly higher as compared to that of the monomer. At 8 h p.i., tumour uptake of the tetramer (7.40+/-1.12%ID/g) was significantly higher than that of the monomer (2.30+/-0.34%ID/g), p<0.001, and the dimer (5.17+/-1.22%ID/g), p<0.05. At 24 h p.i., the tumour uptake was significantly higher for the tetramer (6.82+/-1.41%ID/g) than for the dimer (4.22+/-0.96%ID/g), p<0.01, and the monomer (1.90+/-0.29%ID/g), p<0.001. CONCLUSION: Multimerisation of c(RGDfK) resulted in enhanced affinity for alpha(v)beta(3) as determined in vitro. Tumour uptake of a tetrameric RGD peptide was significantly higher than that of the monomeric and dimeric analogues, presumably owing to the enhanced statistical likelihood for rebinding to alpha(v)beta(3).

Animals↗
PubMed2006

Imaging hypoxia after oxygenation-modification: comparing [18F]FMISO autoradiography with pimonidazole immunohistochemistry in human xenograft tumors.

PURPOSE: Hypoxia is one of the reasons for radiation therapy resistance. Positron emission tomography using (18)F-labeled misonidazole ([(18)F]FMISO) is a non-invasive method of imaging tumor hypoxia. Aim of this study was to validate [(18)F]FMISO against the clinically most widely used hypoxic cell marker pimonidazole under different oxygenation conditions. MATERIALS AND METHODS: One human head and neck squamous cell carcinoma (SCCNij3) and two human glioblastoma (E102 and E106) xenograft tumor lines were studied after injection of [(18)F]FMISO and pimonidazole. Control mice were compared with a second group breathing carbogen to reduce tumor hypoxia and with a third group with clamped tumors to increase hypoxia. Tumor sections were analyzed on a phosphor imaging system and consecutively stained immunohistochemically (IHC) for visualization of pimonidazole. Pixel-by-pixel analysis was performed and the hypoxic fraction, obtained after segmentation of the pimonidazole signal, was related to the mean optical density of [(18)F]FMISO and pimonidazole. RESULTS: A moderate pixel-by-pixel correlation between [(18)F]FMISO autoradiography and pimonidazole IHC was found for the control tumors, after carbogen breathing and after clamping for SCCNij3. For E102 and E106, mean signal intensities for pimonidazole significantly decreased after carbogen breathing and increased after clamping, mean [(18)F]FMISO signal intensities increased significantly after clamping and a significant correlation between the hypoxic fractions and the mean [(18)F]FMISO signal intensities was found. CONCLUSIONS: [(18)F]FMISO autoradiography and pimonidazole immunohistochemistry can both be used to visualize treatment induced changes in tumor hypoxia. However, the response to these modifications differs widely between xenograft tumor lines.

Animals↗
PubMed2006

Caffeine prevents protection in two human models of ischemic preconditioning.

OBJECTIVES: We studied whether caffeine impairs protection by ischemic preconditioning (IP) in humans. BACKGROUND: Ischemic preconditioning is critically dependent on adenosine receptor stimulation. We hypothesize that the adenosine receptor antagonist caffeine blocks the protective effect of IP. METHODS: In vivo ischemia-reperfusion injury was assessed in the thenar muscle by 99mTc-annexin A5 scintigraphy. Forty-two healthy volunteers performed forearm ischemic exercise. In 24 subjects, this was preceded by a stimulus for IP. In a randomized double-blinded design, the subjects received caffeine (4 mg/kg) or saline intravenously before the experiment. At reperfusion, 99mTc-annexin A5 was administered intravenously. Targeting of annexin was quantified by region-of-interest analysis, and expressed as percentage difference between experimental and contralateral hand. In vitro, we assessed recovery of contractile function of human atrial trabeculae, harvested during heart surgery, as functional end point of ischemia-reperfusion injury. Field-stimulated contraction was quantified at baseline and after simulated ischemia-reperfusion, in a paired approach with and without 5 min of IP, in the presence (n=13) or absence (n = 17) of caffeine (10 mg/l). RESULTS: Ischemic preconditioning reduced annexin targeting in the absence of caffeine (from 13 +/- 3% to 7 +/- 1% at 1 h, and from 19 +/- 2% to 9 +/- 3% at 4 h after reperfusion, p = 0.006), but not after caffeine administration (targeting 11 +/- 2% and 16 +/- 3% at 1 and 4 h). In vitro, IP improved post-ischemic functional recovery in the control group, but not in the caffeine group (8 +/- 3% vs. -8 +/- 5%, p=0.003). CONCLUSIONS: Caffeine abolishes IP in 2 human models at a dose equivalent to the drinking of 2 to 4 cups of coffee. (The Effect of Caffeine on Ischemic Preconditioning; http://clinicaltrials.gov/ct/show/NCT00184912?order=1; NCT00184912).

Adult↗
PubMed2006

Scintigraphic imaging of P-glycoprotein expression with a radiolabelled antibody.

PURPOSE: P-glycoprotein (P-gp) is a membrane efflux pump protein that is involved in multidrug resistance (MDR). Tumour cells with high P-gp expression show poor response to cancer treatment with several chemotherapeutics. In vivo targeting and visualisation of P-gp expression would allow MDR to be evaluated non-invasively prior to treatment. The aim of this study was to investigate the feasibility of visualising P-gp expression in tumours using a monoclonal anti-P-gp antibody, 15D3. METHODS: Nude BALB/c mice with subcutaneously growing human uterine sarcoma cell tumours with either high (MES-SA/Dx5 1977) or low (MES-SA 1976) P-gp expression were used. When tumours were 0.2-0.4 g, mice received (131)I-15D3 or (111)In-DTPA-15D3 monoclonal anti-P-gp antibody intravenously. Images were acquired up to 3 days p.i. and radioactivity concentration in various tissues was determined after euthanisation of the animals. RESULTS: The images demonstrated that radioactivity accumulated to a higher concentration in high P-gp expressing tumours than in the low P-gp expressing MES-SA 1976 tumour. Furthermore, visualisation of the P-gp expressing tumours was superior with (111)In-DTPA-15D3 than with (131)I-15D3. After injection of (111)In-DTPA-15D3, the high P-gp expressing MES-SA/Dx5 1977 tumours were clearly visualised at 3 days p.i. The biodistribution data indicated that radioactivity concentration in the high P-gp expressing tumours was higher than in the tumours with low P-gp expression (20.78+/-1.42 %ID/g for MES-SA/Dx5 1977 tumours and 8.39+/-3.78 %ID/g for MES-SA 1976 tumours for (111)In-DTPA-15D3). CONCLUSION: The (111)In-labelled monoclonal anti-P-gp antibody clearly visualised P-gp expression in a human uterine sarcoma tumour in nude mice.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2006

Improved tumour detection by gastrin receptor scintigraphy in patients with metastasised medullary thyroid carcinoma.

PURPOSE: Radiopeptide imaging is a valuable imaging method in the management of patients with neuroendocrine tumours (NET). To determine the clinical performance of gastrin receptor scintigraphy (GRS), it was compared with somatostatin receptor scintigraphy (SRS), computed tomography (CT) and (18)F-FDG positron emission tomography (PET) in patients with metastasised/recurrent medullary thyroid carcinoma (MTC). METHODS: Twenty-seven consecutive patients underwent imaging with GRS, SRS (19 patients), CT and PET (26 patients). GRS and SRS were compared with respect to tumour detection and uptake. CT, PET, magnetic resonance imaging (MRI), ultrasound (US) and follow-up were used for verification of findings. In addition, GRS, CT and PET were directly compared with each other to determine which method performs best. RESULTS: Nineteen patients underwent both GRS and SRS. Among these, GRS showed a tumour detection rate of 94.2% as compared to 40.7% for SRS [mean number of tumour sites (+/-SD) and 95% confidence intervals (CI): GRS 4.3+/-3.1/2.8-5.7, SRS 1.8+/-1.6/1.1-2.6]. In 26 patients, GRS, CT and PET were compared. Here, GRS showed a tumour detection rate of 87.3% (CT 76.1%, PET 67.2%; mean number of tumour sites and 95% CI: GRS 4.5+/-4.0/2.9-6.1, CT 3.9+/-3.5/2.5-5.3, PET 3.5+/-3.3/2.1-4.8). If GRS and CT were combined, they were able to detect 96.7% of areas of tumour involvement. CONCLUSION: GRS had a higher tumour detection rate than SRS and PET in our study. GRS in combination with CT was most effective in the detection of metastatic MTC.

Adult↗
PubMed2006

Effects of hyperoxygenation on FDG-uptake in head-and-neck cancer.

PURPOSE: Tumor hyperoxygenation results in high response rates to ARCON (accelerated radiotherapy with carbogen and nicotinamide). The effect of hyperoxygenation on tumor metabolism using [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) was investigated. METHODS: Within one week, FDG-PET was performed without and with hyperoxygenation by carbogen breathing and/or nicotinamide administration in 22 patients, eligible for ARCON for head-and-neck cancer. Maximum standardized uptake values (SUV(max)) in both scans and the relative change were calculated in the primary tumor and in normal muscle. RESULTS: Alteration of the tumor oxygenation state induced profound, but variable, metabolic changes (median DeltaSUV(max) -4%; range -61% to +30%). Metabolism in normal muscle was not affected. In three patients who did not achieve local tumor control, the SUV(max) after hyperoxygenation differed less than 5% change as compared to baseline, whereas 13 of the 16 patients with local tumor control showed a larger difference (p<0.05). CONCLUSION: Given the heterogeneous response pattern of nicotinamide and carbogen on FDG-uptake in head-and-neck carcinoma, the prognostic significance of semiquantitative FDG-PET before and after hyperoxygenation remains uncertain and requires confirmation in larger clinical studies before introducing the procedure as a predictive tool for oxygenation modifying treatments.

Aged↗