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X Marchandise

Publications and source records attributed to X Marchandise.

At least 37 records · Page 2Linked to original sources
PubMed1998

Measurement of bone mineral density in mother-daughter pairs for evaluating the family influence on bone mass acquisition: a GRIO survey.

The relative influence of genetic and environmental determinants on bone mass is still unclear. Using an original multicentric mode of recruitment, based on absorptiometry current practice, the hypothesis of a familial predisposition to low bone mineral content was assessed. The study was based on dual-energy X-ray absorptiometry (DXA) measurements of lumbar and femoral neck bone mineral density (BMD), using daughters of women with a low BMD (case mothers). These BMD values were compared with those of control daughters of women with a normal BMD. Case mothers (n = 72) aged 54.3 +/- 4.8 years were recruited on the basis of a questionnaire and a vertebral Z-score < -2 SD. Their healthy daughters of more than 20 years (n = 77) aged 28.2 +/- 4.9 years had their vertebral and femoral BMD Z-score determined. The control groups were composed of mothers aged 54.1 +/- 4.7 years, paired by age +/- 2 years to the case mothers, and of their daughters of more than 20 years old, aged 27.7 +/- 5.8 years. For daughters, a significant difference was found between the mean vertebral Z-scores (-0.82 +/- 1.08 for cases and 0.01 +/- 1.14 for controls, p < 0.0001). The difference was in the same direction but was not statistically significant for mean femoral Z-scores (-0.58 +/- 1.15 for cases and -0.22 +/- 1.33 for controls, p < 0.073). These findings confirm the hypothesis of a familial predisposition to low BMD.

Absorptiometry, Photon↗
PubMed1998

Intraoperative gastrin measurements during surgical management of patients with gastrinomas: experience with 20 cases.

Despite recent advances in imaging techniques for endocrine tumors of the duodenum and the pancreas, preoperative localization of gastrinomas is inconsistent. Successful surgical management of patients with Zollinger-Ellison syndrome (ZES) and removal of all gastrin-secreting tumors remains a difficult task. The aim of the study was to evaluate the predictive value of intraoperative gastrin measurements for successful surgical treatment in patients with gastrinomas. Intraoperative gastrin measurements were performed in 20 patients with ZES who underwent resection of gastrin-secreting tumors. Gastrin was measured with a radioimmunologic assay in blood samples obtained from a peripheral vein and from the portal vein at the beginning of the operation (T0) and 20 minutes after removal of the lesion(s) (T1). In 16 patients gastrin was also measured 4 minutes after injection of secretin 3 U/kg (T2). Thirteen patients (65%) were cured by surgery. In two of them, peripheral and portal gastrin levels were normal at T0, precluding any further interpretation of the test. Completeness of surgery was confirmed by normalization of gastrin levels at T1 or the absence of stimulation at T2 (or both) in 10 patients. In only one case did the gastrin levels remain elevated at T1 despite a favorable outcome after surgery. In each of the seven patients (35%) who had persisting disease at 1 year, failure of the surgical procedure was predicted by persistence of high levels of gastrin at T1. In patients with hypergastrinemia, the positive predictive value of intraoperative gastrin measurement for completeness of surgery and the specificity were 100%. The negative predictive value was 88% and the sensitivity 91%. The overall accuracy of the test was 94%. In patients with ZES the normalization of systemic hypergastrinemia during surgery affirms the successful removal of all gastrin-secreting tumors. We conclude that intraoperative gastrin measurement is a valuable addendum for optimizing the surgical management of gastrinoma.

Gastrins↗
PubMed1998

Right ventricular ejection fraction is an independent predictor of survival in patients with moderate heart failure.

OBJECTIVES: We sought to study the relationship between survival and right ventricular ejection fraction (RVEF) in a subgroup of patients with moderate congestive heart failure (CHF). BACKGROUND: It has been demonstrated that RVEF is an independent predictor of survival in patients with advanced CHF. METHODS: Cardiopulmonary exercise testing and radionuclide angiography (to determine right and left ventricular ejection fraction) were prospectively performed in 205 consecutive patients with moderate CHF (140 patients in New York Heart Association [NYHA] class II, 65 in class III). RESULTS: Left ventricular ejection fraction was 29.3%+/-10.1%, RVEF was 37.5%+/-14.6% and peak oxygen consumption (VO2) was 16.2+/-5.4 ml/min/kg (60.2%+/-19% of maximal predicted VO2). After a median follow-up period of 755 days, there were 44 cardiac-related deaths, 3 deaths from noncardiac causes and 15 transplantations of whom 2 were urgent; 1 patient was lost to follow-up. Multivariate analysis showed that three variables-NYHA classification, percent of maximal predicted VO2 and RVEF-were independent predictors of both survival and event-free cardiac survival. Left ventricular ejection fraction and peak VO2 normalized to body weight had no predictive value. The event-free survival rates from cardiovascular mortality and urgent transplantation at 1 year were 80%, 90% and 95% in patients with an RVEF <25%, with a RVEF > or =25% and <35% and with a RVEF > or =35%, respectively. At 2 years, survival rates were 59%, 77% and 93% in the same subgroups, respectively. CONCLUSIONS: In addition to the NYHA classification and to the percent of maximal predicted VO2, RVEF is an independent predictor of survival in patients with moderate CHF.

Disease-Free Survival↗
PubMed1998

CT scan texture analysis of the distal radius: influence of age and menopausal status.

OBJECTIVES: To gain information on bone architecture by performing bone texture analysis in a sample of women covering a broad age range. PATIENTS AND METHODS: We studied 29 healthy women aged 23 to 80 years (55 +/- 18 years), 19 of whom were postmenopausal. None was taking drugs known to influence bone mass or bone metabolism. Computed tomography of the nondominant distal radius was performed with 1 mm slice thickness and 1 mm gap. Four consecutive coronal and four consecutive axial sections were selected for each patient and entered into a PC-type computer. Bone texture was evaluated using grey level run length analysis (five parameters), differential local variation analysis (four parameters), fractal analysis (two parameters), trabecular network extraction and three-dimensional relief characterization. The mean of each study parameter for the four coronal sections and for the four axial sections was calculated. Absorptiometry was done in 16 patients. RESULTS: Linear correlations with age were strongest (P < 0.001) for parameters measured on coronal sections by trabecular network extraction, i.e., trabecular bone volume (r = -0.68), trabecular plate separation (r = -0.65), total skeletal length (r = -0.71), number of nodes (r = 0.73), number of node-node segments (r = -0.74) and trabecular bone pattern factor (r = 0.71). Also, these parameters were significantly different between premenopausal women (33 +/- 9 years) and postmenopausal women (67.3 +/- 9 years). Correlations between bone mineral density and texture parameters were few in number and modest in strength, suggesting that the parameters measured may reflect bone structure rather than bone mass. CONCLUSION: Bone texture in women undergoes changes with advancing age that may reflect alterations in bone microarchitecture.

Adult↗
PubMed1998

Is bone turnover a determinant of bone mass in rheumatoid arthritis?

OBJECTIVE: To study the relationship between bone turnover markers and bone mineral density in patients with rheumatoid arthritis. METHODS: We studied 54 patients, 24 of whom were receiving low dose steroids, and compared them to 54 age and sex matched controls. RESULTS: An 8.2% decrease of femoral neck bone mineral density (BMD) was found in patients not taking steroids compared with controls (confidence interval 1.2-15.3%). Serum markers of bone turnover -- namely, procollagen type I C-terminal propeptide (PICP) and procollagen type I N-terminal propeptide (PINP), which reflect bone formation, and procollagen type I C-terminal telopeptide, which reflects bone resorption -- were significantly increased compared with controls (p < 0.05, p < 0.01, p < 0.01, respectively). Both PINP levels and PICP levels were correlated with the femoral neck BMD as well as osteocalcin levels: R = -0.32 (p < 0.05), R = -0.29 (p < 0.05), and R = -0.42 (p < 0.01), respectively. The best independent predictors of bone mass (stepwise multiple regression analysis) at the femoral neck were steroid use, osteocalcin levels, age, height, the presence of rheumatoid factor, and the Health Assessment Questionnaire score, which explained 61.6% of the variance in femoral neck BMD. CONCLUSION: Elderly patients with RA using steroids with severe disease and high levels of osteocalcin have marked osteoporosis at the hip.

Adult↗
PubMed1997

[Body composition during HIV infect: physiopathology, methods of measurement and review of results].

The immunological linkage between infection and nutritional status was well established even before the AIDS epidemic. AIDS-associated malnutrition alters cellular immunocompetence by decreasing phagocytic function, antibodies secretion, complement system, and number of lymphocytes. Vitamin and oligofactors deficiency increases the dysimmunity. Relations between nutritional status, infectious disease, and immunity system suggest that nutrition could act as a co-factor in the HIV progression. Correlation between survival and weight loss has been shown. Death occurs when loss of 50% of the lean body mass or of 34% of body weight is observed. Furthermore body composition studies have displayed a decrease of body cell mass out of proportion with the discharge in fat or weight. But what is not yet correctly identified is the impact of malnutrition on immunocompetence of a given subject. A significantly longer survival seems likely in patients whose body cell mass is over 30% of total weight, or whose albumin level goes beyond 30 g/L, this criterian being non-specific; parameters of nutritional status are independent of CD4 lymphocytosis, and would have a high predictive value of the survival time. So, early screening of body composition alterations must be used to identify the sligh test erosion of lean mass, as soon as seroconversion is known, even during treatments, using non-invasive, non-expensive, reproducible methods (and no longer weight loss only). This preventive attitude will increase metabolism knowledge about seropositivity status, in time for carrying out adjusted realimentation measures, for providing planned physical activity advice to develop muscular mass.

Body Composition↗
PubMed1997

Somatostatin receptor imaging in somatotroph and non-functioning pituitary adenomas: correlation with hormonal and visual responses to octreotide.

OBJECTIVE: A multicentre study was undertaken to determine the value of somatostatin receptor (sst) scintigraphy in predicting hormonal and visual responses to octreotide treatment in GH-secreting and non-functioning pituitary adenomas. SUBJECTS AND METHODS: Somatostatin receptor scintigraphy was performed in 48 patients (19 acromegaly, 29 non-functioning pituitary adenomas with ophthalmological defects). Results were expressed as an uptake index of the pituitary area. A threshold for positivity was determined in 23 subjects considered as controls. Thirty-five patients were treated for 1 month with octreotide (300 micrograms daily). The therapeutic response was assessed on GH and IGF-I suppression or evolution of the ophthalmological defects. The relationships between the somatostatin receptor scintigraphy result, the therapeutic effect of octreotide and in vitro studies performed in 12 tumours were studied. RESULTS: From the results of control subjects the uptake index threshold for positivity was 2. In patients, somatostatin receptor scintigraphy was positive in 64% and there was no relationship between uptake index and tumour size. In GH tumours, somatostatin receptor scintigraphy was positive in 68%; uptake index was related to octreotide-induced GH and IGF I suppression. The positive predictive value was 100% and the negative predictive value was 50%. In vitro studies showed detectable binding sites for somatostatin with sst2 and sst5 expression in the 4 GH tumours studied although somatostatin receptor scintigraphy was negative in 2 cases. In non-functioning pituitary adenomas somatostatin receptor scintigraphy was positive in 62%. Based on visual effects, the positive predictive value was 61% and the negative predictive value was 100%. A wide distribution of somatostatin binding sites was found in 8 non-functioning pituitary adenomas with expression of sst2 only. CONCLUSION: In the conditions of the study, in patients with acromegaly, positive somatostatin receptor scintigraphy predicts a hormonal response but the value of somatostatin receptor scintigraphy is limited by its low negative predictive value. In patients with non-functioning pituitary adenomas, negative somatostatin receptor scintigraphy predicts that there will be no visual improvement during octreotide treatment.

Acromegaly↗
PubMed1997

'Localized amyloidosis': 123I-labelled SAP component scintigraphy and labial salivary gland biopsy.

In apparently localized amyloidosis, there is no appropriate test to determine whether systemic deposits exist. We studied the value of serum amyloid P component (SAP) scintigraphy and labial salivary gland (LSG) biopsy on patients with apparently localized amyloidosis in 12 patients who had neither clinical nor biological evidence of systemic amyloidosis. All patients had an LSG biopsy and echocardiography. Iodine-123-labelled serum amyloid P component (123I-SAP) scintigraphy was performed in all patients. Whole-body scintigraphy was done, and tissue retention was evaluated at 24 h and 48 h. Of these 12 patients, three had amyloidosis in their LSG and had abnormal 123I-SAP scintigraphy; these three had a secondary clinical history of systemic amyloidosis. Three other patients had abnormal 123I-SAP scintigraphy without detectable systemic amyloid deposits, but one had a previous history of bilateral carpal tunnel syndrome treated with infiltration. 123I-SAP scintigraphy in association with LSG biopsy may be helpful in determining the localized or systemic character of amyloid disease.

Adult↗
PubMed1997

Contribution of calcaneal ultrasonic assessment to the evaluation of postmenopausal and glucocorticoid-induced osteoporosis.

We evaluated ultrasound propagation through the calcaneus using the Achilles Lunar unit in patients with postmenopausal or glucocorticoid-induced osteoporosis. Speed of sound, broadband ultrasound attenuation and a combination of these two parameters called stiffness were determined. Reproducibility was 0.23%, 2.6%, and 2.6% for these three parameters, respectively. Bone mineral density measured at the spine and femoral neck by absorptiometry was significantly correlated with all three ultrasound parameters in the women with postmenopausal osteoporosis (n = 47) and in the controls (n = 42). In the patients with glucocorticoid-induced osteoporosis (n = 35), only speed of sound was significantly correlated with the bone mineral density measurements. Mean values in the subjects with postmenopausal osteoporosis and in their age-matched controls were 1473 +/- 27.2 m/sec versus 1500.6 +/- 29.6 m/sec for speed of sound, 95.3 +/- 9.6 dB/Mhz versus 105.7 +/- 10.1 dB/Mhz for broadband ultrasound attenuation, and 56.1 +/- 13.2 versus 70.9 +/- 14.1 for stiffness, indicating a significant difference (P < 0.01). Z scores were -0.91, -1.1, -0.93, -0.97, and -1.05 for bone mineral density at the spine, bone mineral density at the femoral neck, speed of sound, broadband ultrasound attenuation and stiffness, respectively. Receiver Operating Characteristic curves showed that there were no statistically significant differences between the ultrasound parameters at the calcaneus and the absorptiometry measurements at the spine and femoral neck. Mean values in glucocorticoid-treated patients and age-matched controls were 1480 +/- 26.9 m/sec versus 1505.1 +/- 30.3 m/sec for speed of sound, 99.2/-11.4 dB/Mhz versus 105.9 +/- -10.2 dB/Mhz for broadband ultrasound attenuation, and 60.7 +/- 14 versus 72.1/14.5 for stiffness, again indicating a significant difference (P < or = 0.01). Z scores were -0.55, -0.65, -0.8, -0.67, and -0.78 for bone mineral density at the spine, bone mineral density at the femoral neck, speed of sound, broadband ultrasound attenuation and stiffness, respectively. Our data suggest that ultrasound parameters measured at the calcaneus are useful for evaluating postmenopausal and glucocorticoid-induced osteoporosis.

Absorptiometry, Photon↗
PubMed1996

[Preoperative localization of parathyroid lesions with Tc-99m-MIBI/iodine 123].

OBJECTIVE: Assess the sensitivity of MIBI-Tc for the detection of parathyroid lesions and define the threshold of detection by evaluating contrast uptake at 20 minutes and 2 hours. METHODS: Fifty-five operated and cured patients were studied. Image acquisitions were made 20 minutes and 2 hours after injection of 555 MBq MIBI-Tc then 2 hours after injection of 5.55 MBq iodine 123. RESULTS: A total of 87 pathological glands were found including 47 adenomas (80 to 8820 mg) and 40 hyperplasias (44 to 2175 mg). Detection sensitivity was 81% for adenomas and 30% for hyperplasia, but the cell type did not appear to be a determining factor. CONCLUSION: Scintigraphic visualization of parathyroid lesions is more frequent when there is a single lesion. At least one lesion was seen in 80% of the patients. The threshold of detection was 225 mg. Enhancement of parathyroid uptake with MIBI-Tc compared with the thyroid between 20 minutes and 2 hours was not a constant and of unknown origin.

Adenoma↗
PubMed1996

Comparison of somatostatin analogue and metaiodobenzylguanidine scintigraphy for the detection of carcinoid tumours.

The purpose of this prospective study was to compare the ability of radiolabelled somatostatin analogue (RSA) and metaiodobenzylguanidine (MIBG) scintigraphy to display carcinoid tumours. Forty patients were studied after radiological assessment based on clinical symptomatology. These patients had radiologically demonstrated tumours (n=28), resected tumours discovered to be of the carcinoid type (n=5) or clinically and biologically suspected carcinoid tumours (n=7). They underwent indium-111 DTPA-pentetreotide or iodine-123-Tyr-3-octreotide and 131I-MIBG scintigraphy. The results were compared with those of complementary surgical or morphological examinations and analysed according to the site of the tumour and the symptomatology. In the case of 31 patients with a total of 55 tumoral sites, the sensitivity of the initial radiological assessment, of RSA and of MIBG was 96%, 86% and 64%, respectively, for the detection of at least one tumour per patient, but 51%, 85% and 51%, respectively, for the total number of sites. No site was detected solely by MIBG. The concordance between RSA and MIBG was better when all sites were considered (kappa index+0.44) than for only extrahepatic abdominal tumoral sites (kappa index+0.095). Abdominal, thoracic or bone marrow tumours were more easily detected with RSA than with MIBG. Hepatic invasion (21 cases) was more easily detected by radiology (sensitivity 100%) than by RSA and MIBG, both of which displayed a sensitivity of 80%, but with differences in uptake intensity. Tumour detection using MIBG was more significantly linked with flush (P<0.01) than with diarrhoea (P>0.10). In the assessment of carcinoid tumours, RSA scintigraphy should be carried out initially (just after hepatic ultrasonography) and supplemented by MIBG, as comparison of the studies serves to guide therapeutic options and might be valuable for prognosis.

3-Iodobenzylguanidine↗
PubMed1996

Prospective and serial study of primary amyloidosis with serum amyloid P component scintigraphy: from diagnosis to prognosis.

OBJECTIVE: The purpose of this study was to assess the value of the serum amyloid P (SAP) component scintigraphy in patients with primary amyloidosis (AL). MATERIAL AND METHODS: Pure human SAP labeled with iodine-123 (123I-SAP) was given intravenously to 24 patients with biopsy-proven systemic amyloidosis (15 without multiple myeloma = group 1, and 9 with multiple myeloma = group 2) and to 6 patients with multiple myeloma without any clinical or biological signs of amyloidosis (group 3). Whole-body images as well as regional views and tissue retention levels were obtained after 24 hours. Our study was approved by the institutional review committee and all individuals gave informed consent and were prospectively studied (median 13 months, range 1 to 47 from the date of the scintigraphy to May 1995). RESULTS: Organ localization of 123I-SAP, indicating the presence of substantial visceral amyloid deposits, was observed in all patients in group 1 and 2. The organ uptake of 123I-SAP included the spleen (1 patient was splenectomized) in 20 of 23 cases (87%), the liver in 15 of 24 (60%), and the kidneys in 6 of 24 (25%). Myocardial 123I-SAP was never seen although 13 out of the 24 patients had clinical or echographic data for amyloidosis. Twenty-four hour tissue retention was significantly elevated in all patients (group 1 and group 2): 55.66% +/- 19.16% in group 1 and 34.37% +/- 24.92% in group 2, as compared with normal levels < 24%. The sensitivity of the technique was 79% when only organ uptake was considered but reached 100% when tissue retention was also considered. The 24-hour tissue retention might be correlated with the severity of the amyloidosis: mean survival in patients with tissue retention greater than 50% was 11.3 months versus 24.5 months in patients with levels less or equal to 50%. Five of the 6 patients with multiple myeloma without evidence of amyloidosis had abnormal 123I-SAP imaging and 24-hour tissue retention levels. In 2 of them, amyloidosis was secondly detected. In the 9 patients who had two scintigraphies, variations in 24-hour tissue retention values were in accordance with the clinical evaluation. CONCLUSIONS: Spleen and liver distribution of amyloidosis is mostly revealed by 123I-SAP scintigraphy in patients with AL amyloidosis. The uptake of 123I-SAP appeared in proportion to the quantity of amyloidosis present in different tissues, and the relative quantity of amyloid deposits in the myocardium, carpal tunnel, digestive tract, and kidneys was often small and seldom visualized by 123I-SAP scintigraphy. In contrast 24-hour tissue retention levels were abnormal in all cases of known AL amyloidosis. This may be a positive argument for the diagnosis of amyloidosis when histopathological tests are normal. Tissue retention levels appear important as they may be correlated with survival.

Aged↗
PubMed1996

Diagnosis of pulmonary embolism with spiral CT: comparison with pulmonary angiography and scintigraphy.

PURPOSE: To evaluate the accuracy of spiral computed tomography (CT) in the noninvasive diagnosis of pulmonary embolism (PE). MATERIALS AND METHODS: A prospective study was performed in 75 patients who were evaluated with spiral CT and pulmonary angiography of each lung to detect central PE; 25 of the patients also underwent ventilation-perfusion (V-P) scanning. RESULTS: Spiral CT scans were technically suboptimal in three patients. CT and angiographic findings were negative for PE in 25 patients; one patient had false-negative CT findings. Findings from both studies were positive in 39 patients. CT findings of 188 central emboli corresponded exactly to those of angiography. Ten emboli were depicted only on CT scans, whereas seven emboli were identified only on angiograms because of inadequate depiction of the pulmonary arteries in the plane of the CT scans (n = 5) or because of misinterpretation of CT findings (n = 2). The prospective sensitivity of CT was 91%, the specificity was 78%, the positive predictive value was 100%, and the negative predictive value was 89%. Technical failures (n = 3) and inconclusive CT findings (n = 7) were the major limitations of spiral CT. Spiral CT enabled accurate classification of PE in 16 patients with indeterminate (n = 7) and low (n = 9) probability of PE on V-P scans. CT demonstrated central PE in two patients with normal V-P scans. CONCLUSION: Spiral CT can reliably depict central PE and may be introduced into the classic diagnostic algorithms.

Adult↗
PubMed1996

[Gonadotropi adenoma linking labeled somatostatin analogs. Lack of relationship with therapeutic effect].

Somatotropin- and thyrotropin-secreting adenomas are well known for positive uptake of radio-labeled octreotide in vivo, this fact is not so well assessed for gonadotropin-secreting adenomas (GSA). We report one case of positive somatostatin receptor scintigraphy in a woman suffering from histologically proven GSA. This 63 year old patient has been suffering for two years of akinetic syndrome when the outcome of diplopia led to the discovery of a large hypophyseal tumor spreading till V3 floor and in left cavernous sinus by resonance magnetic imaging (RMI). Clinical examination showed anterior hypopituitarism and bitemporal hemianopsia. Biologically, blood gonadotropins were decreased more on LH (0.6 UI/l, N > 15) than on FSH (10 UI/l; N > 20). A lack of response of gonadotropins to LHRH with low blood estradiol concentration (< 10 pg/ml) was noticed. Basal blood measurement of alpha subunit was at 0.17 microgram/l (N = 0.10-1.6) and increased at 0.39 microgram/l after stimulation by LHRH. Although in low range of normal values, other hypophyseal hormones were normal except prolactinemia (45 mg/L; N < 20), however stimulated by TRH and related to dopaminergic deconnection; Indium 111 labeled octreotide scintigraphy showed an over uptake of the tumor. Three month treatment by octreotide (100 micrograms x 3/day subcutaneously) did not allow to decrease significantly FSH concentration or to reduce the tumoral mass. Incomplete removal of the tumor was performed by transphenoidal route. Immunohistochemical analysis revealed positive immunostaining for alpha subunit and FSH beta on numerous cells while the labeling was slightly less strong for LH beta. These data evoked a GSA. This case record depicts the possibility of detection of GSA by somatostatin receptor imaging. However a positive result does not preclude of somatostatin analog therapeutic efficiency.

Adenoma↗
PubMed1995

Treatment planning optimization by conjugate gradients and simulated annealing methods in stereotactic radiosurgery.

PURPOSE: This paper presents a new optimization method of treatment planning in linac stereotactic radiosurgery. METHODS AND MATERIALS: On a workstation integrating x-rays, computed tomography (CT), magnetic resonance imaging (MRI), and digital subtracted angiography (DSA) images, we first determine the outlines of the target volume and surrounding healthy tissues to spare. To achieve complete optimization of the treatment plans, this method decomposes the optimization process in two steps. The position of the isocenters and the diameter of the collimators are first deduced by a conjugate gradients method, from the position and size of ellipsoids or spheres modeling the target volume. The other irradiation parameters, such as the isocenter dose, the aperture, and the weight of each irradiation plane and of their irradiation sectors are finally deduced by a simulated annealing optimization algorithm. RESULTS: The system can perform multitarget/multisector treatment plans that are automatically obtained in a satisfactory time (as a rule, 20 min for a two-target irradiation), much faster than the time needed for a manual treatment planning. We present the results in two cases: the simulation of a single-target treatment and a two-target real treatment with constraints. In these two cases, we can control the dose received by target and sensitive volumes. CONCLUSION: This method achieves an excellent conformation of the estimated isodose curves with the outlines of the target volume, which allows us to avoid the surrounding healthy tissues, thanks to the different weighting factors given on each volume concerned according to the importance we grant to each of them.

Angiography, Digital Subtraction↗
PubMed1995

A frameless stereotaxic localisation system using MRI, CT and DSA.

The authors present a method of stereotaxic localisation using magnetic resonance imaging (MRI) computerized tomography (CT) and digital subtracted angiography (DSA) which does not require localisation frams fixed to the patient's skull, but uses only four cranial landmarks corresponding to the holders of the neurosurgical stereotaxic frame. The method presents no major constraints in routine examinations. The geometrical distortions of the imaging devices are corrected. Three-dimensional localisation is performed using sagittal and axial slices in MRI, axial slices in CT and only two associated frontaly and lateral views in DSA. The images data are transferred to a PC-based system. By locating the landmarks on the images, the transformation matrixes can be computed to obtain the 3D coordinates of a target in the stereotaxic space and in any imaging modality. The results obtained show the precision of the corrections and the millimetre accuracy of pin-point target localisation.

Angiography, Digital Subtraction↗
PubMed1995

Comparison of technetium-99m methoxyisobutylisonitrile and gallium-67 citrate scanning in the assessment of lymphomas.

The aim of this study was to compare the value of scintigraphy using technetium-99m methoxyisobutylisonitrile (MIBI) with that of scintigraphy using gallium-67 citrate in the assessment of Hodgkin's disease and non-Hodgkin's lymphoma and to relate these results with those of CT scan and MRI. Fifty-eight patients were included either for a follow-up examination or for monitoring of their treatment. Twenty-three residual masses were studied. A whole-body scan was performed, followed by single-photon emission computed tomography (SPET) 20 min after injection of 740 MBq of 99mTc-MIBI and 72 h after injection of 185 MBq of 67Ga citrate. The overall sensitivity of 99mTc-MIBI and 67Ga citrate was 71% and 68%, respectively, and the overall specificity was 76% and 44%, respectively. For residual masses, the sensitivity was 44% with both tracers and the specificity was 80% with 99mTc-MIBI and 53% with 67Ga citrate. The positive predictive values were 85% and 68% and the negative predictive values were 59% and 44%, respectively. The signal-to-background ratio was 1.5 for 99mTc-MIBI and 2 for 67Ga citrate. At present, 99mTc-MIBI cannot replace 67Ga citrate in the assessment of lymphomas.

Adult↗