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R A Dierckx

Publications and source records attributed to R A Dierckx.

At least 19 recordsLinked to original sources
PubMed2002

Quality of life assessment in radionuclide therapy: a feasibility study of the EORTC QLQ-C30 questionnaire in palliative (131)I-lipiodol therapy.

The good tolerance of radionuclide therapy has frequently been proposed as a major advantage. This study explored the feasibility of using the EORTC QLQ-C30 questionnaire in palliative iodine-131 lipiodol therapy for hepatocellular carcinoma. Questionnaires were completed during interviews in which all symptoms, co-morbidity and medication were assessed at baseline within 1 week before (131)I-lipiodol therapy, and subsequently after 1 and 3 months, in 20 patients treated with locoregional, intra-arterial (131)I-lipiodol therapy with or without cisplatin. Principal observations were that (1) a number of important scales, i.e. overall quality of life, physical functioning and pain, worsened between 0 and 3 months after (131)I-lipiodol therapy, irrespective of tumour response, and (2) the occurrence of clinical side-effects was associated with a negative impact on quality of life and physical functioning 1 and 3 months after (131)I-lipiodol. The QLQ-C30 can be regarded as a feasible method for quality of life assessment in (131)I-lipiodol therapy for hepatocellular carcinoma and possibly in other radionuclide therapies. These observations should be related to the impact of other treatment modalities on quality of life.

Aged↗
PubMed2002

Thyroid uptake and radiation dose after (131)I-lipiodol treatment: is thyroid blocking by potassium iodide necessary?

In radionuclide therapy with iodine-131 labelled pharmaceuticals, free (131)I may be released and trapped by the thyroid, causing an undesirable radiation burden. To prevent this, stable iodide such as potassium iodide (KI) can be given to saturate the thyroid before (131)I is administered. The guidelines of the European Association of Nuclear Medicine do not, however, recommend special precautions when administering (131)I-lipiodol therapy for hepatocellular carcinoma. Nevertheless, some authors have reported (131)I uptake in the thyroid as a consequence of such therapy. In this study, the influence of prophylactic KI on the thyroid uptake and dose (MIRD dosimetry) was prospectively investigated. (131)I-lipiodol was given as a slow bolus selectively in the proper hepatic artery or hyperselectively in the right and/or left hepatic artery. Patients were prospectively randomised into two groups. One group received KI in a dose of 100 mg per day starting 2 days before (131)I-lipiodol administration and continuing until 2 weeks after therapy (KI group; n=31), while the other group received no KI (non-KI group; n=37). Thyroid uptake was measured scintigraphically as a percentage of administered activity 7 days after (131)I-lipiodol ( n=68 treatments). The absorbed radiation dose to the thyroid was assessed by scintigraphy after 7 and 14 days using a mono-exponential fitting model and MIRD dosimetry ( n=40 treatments). The mean activity of (131)I-lipiodol administered was 1,835 MBq in a volume of 2 ( n=17) or 4 ( n=51) ml. Thyroid uptake was lower in the KI group, being 0.23%+/-0.06% of injected activity ( n=31) compared with 0.42%+/-0.20% in the non-KI group ( n=37); the mean thyroid dose was 5.5+/-1.6 Gy in the KI group ( n=19) versus 11.9+/-5.9 Gy in the non-KI group ( n=21). These differences were statistically significant ( P<0.001). No effect of the amount of added cold lipiodol (4 vs 2 ml total volume) or selectivity of (131)I-lipiodol administration was evident ( P>0.1). (131)I-lipiodol is associated with a generally low thyroid uptake and dose that may be significantly decreased by KI premedication. Given the low cost and the very good tolerance of the KI treatment, we believe the use of KI should be recommended in the majority of the patients.

Carcinoma, Hepatocellular↗
PubMed2002

Leakage assessment in adjustable laparoscopic gastric banding: radiography versus (99m)Tc-pertechnetate scintigraphy.

The least invasive of all surgical weight-lowering procedures is the adjustable laparoscopic gastric banding (ALGB) technique. A rare complication (0.9%-1.8% of patients) but one that may require surgical revision is leakage of the gastric banding device. This paper reports on the usefulness of technetium-99m scintigraphy for the assessment of gastric band leaks as compared with radiography. Between March 1997 and October 2001, 23 obese patients (20 women and 3 men; mean age 35 years; range 23-60 years; mean body mass index before gastric banding procedure, 39.2 kg/m(2); range 29.3-52.1 kg/m(2)) were referred for exclusion of gastric banding leakage by means of radiography and (99m)Tc-pertechnetate scintigraphy. Both procedures were performed on the same day in all patients. Two patients underwent both procedures, respectively two and three times. A total of 27 radiographic and scintigraphic examinations were performed. Radiographs were judged positive for leakage when escape of contrast agent through a defect in the gastric banding device was visualised or when indirect criteria, e.g. smooth passage of barium suspension through the stoma after injection of contrast agent, were present. Scintigraphic images were judged positive when tracer disappearance out of the banding device and uptake in the thyroid gland as well as enhancement of the gastric mucosa were observed 30 min and/or 3 h post injection. Overall sensitivity, specificity and accuracy for radiography and (99m)Tc scintigraphy were 81.8% vs 81.8%, 75% vs 100% and 77.7% vs 92.6%. Leakage from the reservoir or the connecting tube is a late complication of ALGB. The presented data suggest that (99m)Tc-pertechnetate scintigraphy is more efficient than radiography in determining the presence of such leaks.

Adult↗
PubMed2002

Promising role of 18-F-fluoro-D-deoxyglucose positron emission tomography in clinical infectious diseases.

18-F-fluoro-D-deoxyglucose positron emission tomography (FDG PET) has become an established imaging tool in clinical oncology, cardiology and neurology and is now entering the field of clinical infectious diseases. The purpose of this article is to review the currently available, albeit limited, literature on FDG PET in the diagnosis of various infections and fever of unknown origin. Those indications for which FDG PET offers added value over more available techniques like labelled leucocyte scanning, gallium scanning and magnetic resonance imaging are especially highlighted. FDG PET seems to have an incremental value in the assessment of chronic osteomyelitis, especially in the axial skeleton, as well as in the diagnostic workup of fever of unknown origin and HIV complications. Cost-effectiveness studies are needed to define its place in the current diagnostic strategies of these pathologies.

Fever of Unknown Origin↗
PubMed2002

Combining iodine-131 Lipiodol therapy with low-dose cisplatin as a radiosensitiser: preliminary results in hepatocellular carcinoma.

A prospective pilot trial was performed in 20 patients randomised to receive either (131)I-Lipiodol therapy alone (n=10) or (131)I-Lipiodol combined with a short low-dose cisplatin infusion (n=10), the aim being to evaluate the possible positive influence of a radiosensitiser on toxicity and tumour response. An activity of 1,354-2,128 MBq (mean 1,824 MBq) [36.6-57.5 mCi (mean 49.3 mCi)] (131)I-labelled Lipiodol was administered by selective instillation in the hepatic artery. Cisplatin was given in a dose of 30 mg/m(2) at day -1 and day +6 (day 0: (131)I-Lipiodol). The primary endpoint of this trial was toxicity of therapy; points of secondary interest were tumour response and survival at 6 months. With the use of cisplatin we found a higher percentage of stable or diminished tumour size (90%, vs 40% without). A benefit in group survival at 6 months was not evident. Low-grade stomatitis in one patient and minor changes in peripheral blood count were probably directly related to cisplatin, but its administration is unlikely to be associated with an excess of serious side-effects. The use of low-dose cisplatin infusion as a radiosensitising agent in (131)I-Lipiodol therapy for hepatocellular carcinoma seems safe and may be beneficial for tumour control. Larger patient groups are necessary for confirmation and to establish the future role of (131)I-Lipiodol in hepatocellular carcinoma.

Carcinoma, Hepatocellular↗
PubMed2001

Regional brain activity during different paradigms of mental rotation in healthy volunteers: a positron emission tomography study.

Positron emission tomography (PET) was used to observe changes in regional cerebral blood flow (rCBF) in 10 right-handed healthy volunteers performing two paradigms of mental rotation. In one paradigm, subjects mentally rotated a single alphanumeric stimulus to determine whether it was shown in a normal or mirror-image position. In a second paradigm, subjects mentally rotated and compared pairs of figurative stimuli to determine whether the stimuli were identical or mirror-images. In both paradigms, rCBF was compared with a control task that used identical stimuli, but required no mental rotation. Mental rotation of single alphanumeric stimuli engendered activation in the primary somatomotor area in the left precentral gyrus. Mental rotation of paired figures engendered activation in the left superior parietal lobule and the right frontal medial gyrus. A deactivated area was located in the medial part of the left superior frontal gyrus. Comparison of both paradigms revealed that the left gyrus precentralis was activated significantly during the alphanumeric condition and that the left gyrus lingualis was significantly activated during the paired figures condition. Motor processes may be an inherent part of every mental rotation but the type of motor involvement appears strongly dependent on the specific task or the specific stimuli. Similar paradigms, designed to isolate the same cognitive function, in the same subjects, using the same imaging technology and methodology, but differing only in stimulus material, lead to different areas of neural activation. Task specificity determines the most significant changes in cerebral blood flow in different mental rotation paradigms.

Adult↗
PubMed2001

Decreased frontal serotonin 5-HT 2a receptor binding index in deliberate self-harm patients.

Studies of serotonin metabolites in body fluids in attempted suicide patients and of post-mortem brain tissue of suicide victims have demonstrated the involvement of the serotonergic neurotransmission system in the pathogenesis of suicidal behaviour. Recently developed neuroimaging techniques offer the unique possibility of investigating in vivo the functional characteristics of this system. In this study the 5-HT2a receptor population of patients who had recently attempted suicide was studied by means of the highly specific radio-iodinated 5-HT2a receptor antagonist 4-amino-N-[1-[3-(4-fluorophenoxy) propyl]-4-methyl-4-piperidinyl]-5-iodo-2-methoxybenzamide or 123I-5-I-R91150. Nine patients who had recently (1-7 days) attempted suicide and 12 age-matched healthy controls received an intravenous injection of 185 MBq 123I-5-I-R91150 and were scanned with high-resolution brain single-photon emission tomography (SPET). Stereotactic realigned images were analysed semi-quantitatively using predefined volumes of interest. Serotonin binding capacity was expressed as the ratio of specific to non-specific activity. The cerebellum was used as a measure of non-specific activity. An age-dependent 5-HT2a binding index was found, in agreement with previous literature. Deliberate self-harm patients had a significantly reduced mean frontal binding index after correction for age (P=0.002) when compared with controls. The reduction was more pronounced among deliberate self-injury patients (DSI) (P<0.001) than among deliberate self-poisoning patients (DSP). Frontal binding index was significantly lower in DSI patients than in DSP suicide attempters (P<0.001). It is concluded that brain SPET of the 5-HT2a serotonin receptor system in attempted suicide patients who are free of drugs influencing the serotonergic system shows in vivo evidence of a decreased frontal binding index of the 5-HT2a receptor, indicating a decrease in the number and/or in the binding affinity of 5-HT2a receptors.

Adolescent↗
PubMed2001

Biodistribution and dosimetry of 99mTc-ciprofloxacin, a promising agent for the diagnosis of bacterial infection.

This study reports on the biodistribution and dosimetry of technetium-99m ciprofloxacin, a radio-ligand developed for the visualisation of bacterial infection. Whole body scans were performed up to 24 h after intravenous injection of 370 MBq 99mTc-ciprofloxacin in three male and three female volunteers. Blood samples were taken at various times up to 24 h after injection. Urine was also collected up to 24 h after injection, allowing calculation of renal clearance and interpretation of whole body clearance. Time-activity curves were generated for the thyroid, heart, liver and whole body by fitting the organ-specific geometric mean counts, obtained from regions of interest. The MIRD formulation was applied to calculate the absorbed radiation doses for various organs. The images showed rapid, predominantly urinary excretion of 99mTc ciprofloxacin, with low to absent brain, lung and bone marrow uptake and low liver uptake and excretion. Accordingly, imaging conditions are excellent for both the thoracic and the abdominal region, even at early time points (60 min) post injection. In none of the volunteers was the gallbladder visualised. Approximately 60% of the injected activity was recovered in urine by 24 h post injection. The highest absorbed doses were received by the urinary bladder wall, the thyroid, the upper large intestine, the lower large intestine and the uterus. The estimated mean effective dose for the adult subject, taking into account the weight factors of the ICRP60 publication, was 0.0083 mSv/MBq. The amount of 99mTc ciprofloxacin required for adequate planar and tomographic imaging results in an acceptable effective dose to the patient.

Adult↗
PubMed2001

Age- and gender-specific differences in left ventricular cardiac function and volumes determined by gated SPET.

The aim of this study was to determine normative volumetric data and ejection fraction values derived from gated myocardial single-photon emission tomography (SPET) using the commercially available software algorithm QGS (quantitative gated SPET). From a prospective database of 876 consecutive patients who were referred for a 2-day stress-rest technetium-99m tetrofosmin (925 MBq) gated SPET study, 102 patients (43 men, 59 women) with a low (<10%) pre-test likelihood of coronary disease were included (mean age 57.6 years). For stress imaging, a bicycle protocol was used in 79 of the patients and a dipyridamole protocol in 23. Left ventricular ejection fraction (LVEF) and end-diastolic and -systolic volumes (EDV and ESV) were calculated by QGS. EDV and ESV were corrected for body surface area, indicated by EDVi and ESVi. To allow comparison with previous reports using other imaging modalities, men and women were divided into three age groups (<45 years, > or =45 years but <65 years and > or =65 years). Men showed significantly higher EDVi and ESVi values throughout and lower LVEF values when compared with women in the subgroup > or =65 years (P<0.05, ANOVA). Significant negative and positive correlations were found between age and EDVi and ESVi values for both women and men and between LVEF and age in women (Pearson P< or =0.01). LVEF values at bicycle stress were significantly higher than at rest (P=0.000, paired t test), which was the result of a significant decrease in ESV (P=0.003), a phenomenon which did not occur following dipyridamole stress (P=0.409). The data presented suggest that LVEF and EDVi and ESVi as assessed by QGS are strongly gender-specific. Although the physiological significance of these results is uncertain and needs further study, these findings demonstrate that the evaluation of cardiac function and volumes of patients by means of QGS should consider age- and gender-matched normative values.

Adult↗
PubMed2001

High performance liquid chromatographic determination of 123-I labeled tamoxifen metabolites in human plasma.

A high-performance liquid chromatographic procedure for the quantitation of [(123)I]Iodomethyl-N,N-diethyltamoxifen (ITX), a radioligand for human breast cancer imaging, in human plasma is described. Separation was effected on a RP-C18 column, using a mixture of acetonitrile-water-triethylamine (70/30/0.5, v/v). ITX was rapidly cleared from human plasma and metabolites appeared as early as 7.5 min p.i. Quantitative assessment of metabolites in plasma over time allowed recalculation of the ITX plasma time-activity curve. Implications of ITX metabolite formation for breast tumour imaging are discussed.

Aged↗
PubMed2001

In vivo evaluation of 4-[123I]iodo-N-[2[4-(6-trifluoromethyl-2-pyridinyl)-1-piperazinyl]ethyl]benzamide, a potential SPECT radioligand for the 5-HT1A receptor.

4-[123I]Iodo-N-[2-[4-(6-trifluoromethyl-2-pyridinyl)-1-piperazinyl]ethyl]benzamide (1.123I), a potential SPECT 5-HT(1A) radioligand, was evaluated in vivo in rats. Biodistribution studies were performed leading to a % ID in the brain of 0.22 at 5 min p.i. No significant differences in % ID/g tissue of the different isolated brain regions (hippocampus, hypothalamus, striatum, cortex and cerebellum) could be demonstrated. Blocking experiments with 8-OH-DPAT, WAY100635 and ketanserin could not show any significant change in tracer uptake in the isolated brain regions. These data suggest that uptake in the brain does not represent binding of 1.123I to the 5-HT(1A) receptor.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2001

Synthesis and in vitro evaluation of 123I-labelled human recombinant annexin V.

Annexin V was radiolabelled with iodine-123 in order to develop a SPECT-ligand for imaging atherosclerosis and apoptosis. Iodination by means of electrophylic substitution resulted in radiochemical yields up to 70% and specific activities of 7.4-92.5 MBq/microg protein. Binding experiments with blood platelets indicated that 123I-labelled annexin V remained its biological activity.

Annexin A5↗
PubMed2001

Resolution recovery for list-mode reconstruction in SPECT.

The purpose of the study was to evaluate the resolution recovery in the list-mode iterative reconstruction algorithm (LMIRA) for SPECT. In this study we compare the performance of the proposed method with other iterative resolution recovery methods for different noise levels. We developed an iterative reconstruction method which uses list-mode data instead of binned data. The new algorithm makes use of a more accurate model of the collimator structure. We compared the SPECT list-mode reconstruction with MLEM, OSEM and RBI, all including resolution recovery. For the evaluation we used Gaussian shaped sources with different FWHM at three different locations and three noise levels. For these distributions we calculated the reconstructed images for a different number of iterations. The absolute error for the reconstructed images was used to evaluate the performance. The performance of all four methods is comparable for the sources located in the centre of the field of view. For the sources located out of the centre, the error of the list-mode method is significantly lower than that of the other methods. Splitting the system model into a separate object-dependent and detector-dependent module gives us a flexible reconstruction method. With this we can very easily adapt the resolution recovery to different collimator types.

Algorithms↗
PubMed2001

The anti-tumoral activity of neoadjuvant intra-arterial 131I-lipiodol treatment for hepatocellular carcinoma: a pilot study.

BACKGROUND: The high recurrence rate after curative resection has stimulated the development of adjuvant treatment modalities, such as local embolization. This study was set up to investigate the anti-tumoral potential of neo-adjuvant 131I-lipiodol administration before liver transplantation. METHODS: In this preliminary, prospective study we treated 10 consecutive HCC patients by intra-arterial injection of 131I-lipiodol into the hepatic artery followed by liver transplantation within 1-9 months (mean 3.4). After hepatic catheterization, 1332-2146 MBq (mean 1887 MBq) or 36-58 mCi (mean 51 mCi) was instilled as selective as possible, depending on the distribution of the tumors: non-selectively in the hepatic artery propria (n = 4), selectively in the right and/or left hepatic artery (n = 3) or super-selectively in segmental arteries (n = 3). RESULTS: Anti-tumoral activity was regarded as obvious with 1) a strong decrease of alfa-fetoprotein (AFP), comparing the highest recorded value before and after 131I-lipiodol and/or 2) a downstaging in TNM classification on the posttherapy MRI as compared to the pre-therapy MRI and/or 3) tumors with > 50% necrosis on histo-pathology of the explanted liver, without previous chemoembolization. Either of these criteria were met by 5/10 (50%) of patients. A 4) downstaging in pTNM classification on histopathology compared to the TNM classification of the MRI and/or a 5) tumor necrosis of only 10-50% were regarded as possibly tumor-related but were not accepted as a single criteria of anti-tumoral activity. This was seen in 3/10 (30%) of patients. Clinical side-effects of the 131I-lipiodol therapy were generally mild with a temperature rise in two cases, nausea without vomiting in another two and upper back pain in one patient. In one patient progressive liver failure developed one week after 131I-lipiodol therapy necessitating premature liver transplantation after 4 weeks. CONCLUSION: With the use of stringent anti-tumoral criteria, this study shows evidence of an anti-tumoral effect in 50% of patients. Our data support the evaluation on larger patient numbers to confirm the promising anti-tumoral activity of 131I-lipiodol in HCC patients candidated for liver transplantation.

Aged↗
PubMed2001

Is there a role for agonist gastrin-releasing peptide receptor radioligands in tumour imaging?

Gastrin-releasing peptide (GRP) has been shown to be a tumour growth stimulating agent for a number of normal and human cancer cell lines. The tumour growth effect is a direct result of GRP binding to membrane G-protein coupled GRP receptors (GRP-R) on the cell surface. Available data on the role of GRP and GRP-R in human lung, prostate, breast, colorectal and gastric carcinoma are reviewed and it is suggested that radiolabelled agonists are preferable to antagonists for imaging and therapy as they appear to be internalised, yielding a higher target/background ratio. The use of rhenium or indium radiolabels for therapy may provide a new approach to GRP/bombesin expressing tumours.

Bombesin↗
PubMed2001

The classical stroop interference task as a prefrontal activation probe: a validation study using 99Tcm-ECD brain SPECT.

This study investigated the feasibility of brain single photon emission computed tomography (SPECT) functional imaging in a neuropsychological test setting, following a single-day protocol with a split-dose paradigm. The Stroop Color Word Test (SCWT) is an example of a well-documented prefrontal activation task. In a split-dose protocol, ten right-handed healthy volunteers were injected twice with 370 MBq 99Tcm-ethyl cysteinate dimer while performing consecutively both series of card-reading of the SCWT. Images were reconstructed using filtered back-projection and normalized to a standard template in Talairach coordinates. Statistical Parametric Mapping (SPM96) was used to determine voxelwise significant changes. A first activation cluster was found in the left medial prefrontal cortex, consisting of the gyrus cinguli anterior and the gyrus frontalis medius and superior. A second activation cluster included the right gyrus frontalis dorsalis and medius. These findings confirm to a large extent the results of previous functional magnetic resonance imaging, positron emission tomography studies of Stroop-like tasks. The choice and validity of various methodological characteristics of the experimental design leading to these results is critically discussed. It is concluded that brain SPECT activation with the Stroop Color Word Test under standard neuropsychological conditions in healthy volunteers, is both technically and practically feasible.

Adult↗
PubMed2001

99Tc(m) labelled HL91 versus computed tomography and biopsy for the visualization of tumour recurrence of squamous head and neck carcinoma.

This phase I pilot study reports on (1) the safety and feasibility of 99Tc(m)-HL91, an amine oxime core radioligand that has shown oxygen dependent binding, and imaging; and (2) its usefulness for the visualization of local tumour recurrence of a biopsy proven squamous cell carcinoma of the head and neck (SCCHN) as compared to spiral computed tomogaphy (CT) and biopsy. Nine men (mean age 33 years, range 34-74 years) were prospectively included. For safety measurements, vital signs were recorded and serum chemical analysis carried out, with a complete blood cell count and urine analysis, and an ECG was performed prior to injection of 99Tc(m)-HL91 and repeated during the investigation. Single photon emission computed tomography (SPECT) scans of the head and neck, and of a standard, were performed at 2 h and 4 h post-injection of 740 MBq 99Tc(m)-HL91. Tumour-to-normal tissue background (T/N) ratios and percentage uptake were measured for all 99Tc(m)-HL91 scans. Spiral CT scans were obtained using a Somaton 4+ Siemens scanner within 1 week from the 99Tc(m)-HL91 scans. Based on CT and the 99Tc(m)-HL91 scan findings guided biopsies were performed. No adverse or subjective side effects were noticed. Vital signs, ECG findings, clinical laboratory, blood and urine assays remained stable in all patients. Spiral CT suggested local recurrence in 5/9 patients accompanied by nodal involvement in three, all of which proved positive on biopsy. 99Tc(m)-HL91 scintigraphy was false positive in one patient and true positive (TP) in 3/5 local recurrences and two out of three sites of lymph node involvement depicted by spiral CT. The mean T/N ratios at 2 h and 4 h in TPs were 1.28 (range 1.1-1.66) and 1.40 (range 1.0-1.6), respectively. The corresponding absolute percentages of 99Tc(m)-HL91 lesional uptake at 2 h and 4 h were mu = 0.05% (SD = 0.03%) and mu = 0.048% (SD = 0.035%). The findings suggest 99Tc(m)-HL91 is a safe radioligand and that metabolic binding in a large fraction but not all of local SCCHN recurrences may be expected. The inference that tumour 99Tc(m)-HL91 avidity could be a non-invasive measure of tumour hypoxia deserves however independent confirmation with needle oximetry.

Adult↗