RESUMEN
PURPOSE: To report on the oncological outcomes of active surveillance (AS) in low-grade prostate cancer (PCa) patients using the French SurACaP protocol, with a focus on long-term outcomes. METHODS: This multicenter study recruited patients with low-grade PCa between 2007 and 2013 in four referral centers in France. The cohort included patients meeting the SurACaP inclusion criteria, i.e., aged ≤75years, with low-grade PCa (i.e., ISUP 1), clinical stage T1c/T2a, PSA ≤10ng/mL and ≤3 positive cores and tumor length ≤3mm per core. The SurACaP protocol included a digital rectal examination every six months, PSA level measurement every three months for the first two years after inclusion and twice a year thereafter, a confirmatory biopsy in the first year after inclusion, and then follow-up biopsy every two years or if disease progression was suspected. Multiparametric magnetic resonance imaging (mpMRI) was progressively included over the study period. RESULTS: A total of 86 consecutive patients were included, with a median follow-up of 10.6 years. Only one patient developed metastases and died of PCa. The estimated rates of grade reclassification and treatment-free survival at 15 years were 53.4% and 21.2%, respectively. A negative mpMRI at baseline and a negative confirmatory biopsy were significantly associated with a lower risk of disease progression (P<0.05). CONCLUSIONS: AS using the French SurACaP protocol is a safe and valuable strategy for patients with low-risk PCa, with excellent oncological outcomes after more than 10 years' follow-up. Future studies are crucial to broaden the inclusion criteria and develop a personalized, risk based AS protocol with the aim of de-escalating follow-up examinations. LEVEL OF EVIDENCE: Grade 4.
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Clasificación del Tumor , Neoplasias de la Próstata , Espera Vigilante , Humanos , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/diagnóstico , Masculino , Persona de Mediana Edad , Anciano , Estudios de Seguimiento , Francia/epidemiología , Factores de Tiempo , Antígeno Prostático Específico/sangre , Progresión de la Enfermedad , Tacto Rectal , Estadificación de NeoplasiasRESUMEN
PURPOSE: To report the long-term oncological outcomes of active surveillance (AS) in selected patients with favorable intermediate-risk (IR) prostate cancer (PCa). METHODS: A retrospective database review of two academic centers was conducted to identify favorable IR PCa patients initially managed by AS between 2014 and 2022. Favorable IR PCa was defined by the presence of one single element of IR disease (i.e., PSA 10-20ng/mL, Gleason Grade Group [GG] 2, or cT2b). All patients were diagnosed and followed up according to a contemporary scheme, including MRI and image-guided biopsies. The primary endpoint was metastasis-free survival. RESULTS: A total of 57 patients met our inclusion criteria and the median follow-up was 56months. During follow-up, there were no cases of metastasis or death due to PCa, but 6 deaths due to competing causes. A total of 25 (44%) and 6 patients (11%) had definitive treatment and GG 3 reclassification during follow-up, respectively. In multivariable Cox hazard regression analysis, the risk of undergoing definitive treatment was significantly associated with PSA density>0.15 (HR: 4.82, 95% CI: 1.47 to 15; P=0.01) and PI-RADS 4-5 lesions on mpMRI (HR: 2.48, 95% CI: 1.06 to 5.19; P=0.006). Interestingly, tumor burden (P=0.3) and GG (P=0.7) on biopsy were not associated with definitive treatment. CONCLUSIONS: AS is a safe and valuable strategy for well-selected patients with favorable IR prostate cancer, with excellent oncological outcomes after five years' follow-up.
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Antígeno Prostático Específico , Neoplasias de la Próstata , Masculino , Humanos , Neoplasias de la Próstata/diagnóstico , Imagen por Resonancia Magnética , Estudios Retrospectivos , Espera Vigilante , Biopsia Guiada por ImagenRESUMEN
OBJECTIVE: To assess the contribution of maternal blood detection of IGFBP-1 for the diagnosis of amniotic-fluid embolism in clinical daily practice. DESIGN: A retrospective multicentre cohort study. SETTING: Three tertiary care obstetric units in France. SAMPLE: Data of 86 women for whom amniotic-fluid embolism had been suspected and maternal serum detection of IGFBP-1 had been performed between 2011 and 2019 were analysed. METHODS: The criteria defined by the United Kingdom Obstetric Surveillance System (UKOSS) were used for the retrospective diagnosis of amniotic-fluid embolism. The more structured definition proposed by the Society for Maternal-Fetal Medicine and the Amniotic Fluid Embolism Foundation (SMFM) was also used as secondary endpoint. MAIN OUTCOME MEASURES: Agreements between biological and clinical assessments were tested. The performance of blood detection of IGFBP-1 for the diagnosis of amniotic-fluid embolism according to the UKOSS criteria, and to the SMFM definition, was also assessed. RESULTS: There was only slight agreement between clinical and laboratory diagnosis of amniotic-fluid embolism (Cohen's Kappa coefficient: 0.04). Blood detection of IGFBP-1 had a sensitivity of 16%, a specificity of 88%, a positive and a negative likelihood ratio of 1.3 and 0.95, respectively, and a positive and a negative predictive value of 58 and 50%, respectively, for the diagnosis of amniotic-fluid embolism based on the UKOSS criteria. The use of the more structured SMFM definition of amniotic-fluid embolism did not substantially change the results. CONCLUSION: These results question the usefulness of blood detection of IGFBP-1 for the early diagnosis of amniotic-fluid embolism in daily clinical practice. TWEETABLE ABSTRACT: This retrospective multicentre study questions the contribution of IGFBP-1 detection for the diagnosis of AFE.
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Embolia de Líquido Amniótico/diagnóstico , Proteína 1 de Unión a Factor de Crecimiento Similar a la Insulina/sangre , Pruebas de Detección del Suero Materno/estadística & datos numéricos , Adulto , Femenino , Francia , Humanos , Valor Predictivo de las Pruebas , Embarazo , Reproducibilidad de los Resultados , Estudios Retrospectivos , Sensibilidad y EspecificidadRESUMEN
The spin character of the states at the top of the valence band in doped La(2-x)Sr(x)CuO(4) (x=0.03, 0.07, 0.15, 0.22, and 0.30) has been investigated using spin-polarized resonant photoemission. A clear Zhang-Rice singlet (ZRS) is observed at all doping levels. Its stability and polarization are preserved as a function of doping, suggesting that the concept of the ZRS can be used across a wide doping range and up to the metallic nonsuperconducting overdoped regime. The results are significant for theoretical models that use the ZRS approximation and for the understanding of the peculiar interplay between the ZRS and the remaining localized spins.
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Fibrous media embody the most effective and widely used method of separating ultrafine particles from a carrier fluid. The main problem associated with them is filter clogging, which induces an increasingly marked pressure drop with time and thus imposes regular media cleaning or replacement. This context has prompted the idea of investigating bubble columns, which operate at constant pressure drop, as alternatives to fibrous filters. This study examines the influence of different operating conditions, such as liquid height, air flow rate, bubble size and presence of granular beds on ultrafine particle collection. Experimental results show that bubble columns are characterised by high collection efficiency, when they feature a large liquid height and small diameter bubbling orifices, while their efficiencies remain lower than those of fibrous filters. Gas velocity does not greatly influence collection efficiency, but the inclusion of a granular bed, composed of beads, increases the bubble residence time in the column, thereby increasing the column collection efficiency.
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Contaminantes Atmosféricos/química , Nanopartículas/química , Contaminación del Aire/prevención & controlRESUMEN
The most effective and widely used dedusting techniques to separate nanoparticles of a carrier fluid are fibrous media. The main problem is the clogging of the filter that induces a pressure drop increase over time and thus requires a regular cleaning of the media (or its replacement). Following these observations, this study proposes to investigate the potential of bubble columns for nanoparticles collection. Despite collection efficiencies lower than those of fibrous filters, experimental results show that bubble columns present likely performances for the collection of nanoparticles and have collection efficiency even more important when the liquid height is high and bubbling orifices have low diameters. Experiments have also revealed the presence of a most penetrating particle size for a particle diameter range between 10 and 30 nm. The model developed in this article highlights a good agreement between the theoretical collection efficiency by Brownian diffusion and experimental collection efficiencies for particles lower than 20 nm. Nevertheless, the modelling may be extended to other collection mechanisms in order to explain the collection efficiency increase for particles higher than 20 nm and to confirm or infirm that electrostatic effects can be the cause of this efficiency increase.
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Nanopartículas , DifusiónRESUMEN
Synchrotron stereotactic radiotherapy (SSR) is a treatment that involves selective accumulation of high-Z elements in tumours followed by stereotactic irradiation, in CT mode, with monochromatic X-rays from a synchrotron source, tuned at an optimal energy. The irradiation geometry, characteristic X-rays, photoelectrons, and Auger electrons generated on high-Z atoms by kilovoltage X-rays produce a localized dose enhancement. Two complimentary SSR approaches have been successfully developed in the past 5 years in our team, and may be promising in high-grade glioma management: iodine-enhanced SSR, with an iodinated contrast agent; and Pt-enhanced SSR; a concomitant radio-chemotherapy treatment with locoregional injection of platinated chemotherapy drugs. The results for iodine-enhanced SSR using contrast agents are presented in this paper. IUdR-enhanced SSR was also tested in this study. Up to 15 Gy, intracarotid infusion of iodine significantly improved the rats' survival compared to irradiation alone. SSR provides the most protracted survivals of F98 glioma-bearing rats. The technique is currently transferred to clinical trials. Iodine-enhanced SSR will be implemented first, because of its simplicity; and pave the way for Pt-enhanced SSR, the most efficient technique, but still needing to be improved in terms of intrinsic toxicity.
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Neoplasias Encefálicas/cirugía , Radiocirugia/métodos , Animales , Fenómenos Biofísicos , Biofisica , Medios de Contraste/administración & dosificación , Glioma/cirugía , Humanos , Idoxuridina/administración & dosificación , Yodo/administración & dosificación , Platino (Metal)/administración & dosificación , Ratas , Ratas Endogámicas F344 , SincrotronesRESUMEN
OBJECTIVE: To assess whether patients' perceptions of a hypothetical medical error are influenced by staff responsiveness, disclosure of error, and health consequences of the error. DESIGN: Hypothetical scenario describing a medication error submitted by mail. Three factors were manipulated at random: rapid v slow staff responsiveness to error; disclosure v non-disclosure of the error; and occurrence of serious v minor health consequences. PARTICIPANTS: Patients discharged from hospital. MEASURES: Assessment of care described in the scenario as bad or very bad, rating of care as unsafe, and intent to not recommend the hospital. RESULTS: Of 1274 participants who evaluated the scenario, 71.4% rated health care as bad or very bad, 60.2% rated healthcare conditions as unsafe, and 25.5% stated that they would not recommend the hospital. Rating health care as bad or very bad was associated with slow reaction to error (odds ratio (OR) 2.8, 95% CI 2.1 to 3.6), non-disclosure of error (OR 2.0, 95% CI 1.5 to 2.6), and serious health consequences (OR 3.4, 95% CI 2.6 to 4.5). Similar associations were observed for rating healthcare conditions as unsafe and the intent to not recommend the hospital. Younger patients were more sensitive to non-disclosure than older patients. CONCLUSIONS: Former patients view medical errors less favorably when hospital staff react slowly, when the error is not disclosed to the patient, and when the patient suffers serious health consequences.
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Actitud Frente a la Salud , Relaciones Paciente-Hospital , Hospitales Universitarios/normas , Errores de Medicación/psicología , Calidad de la Atención de Salud/clasificación , Administración de la Seguridad/normas , Revelación de la Verdad , Adolescente , Adulto , Anciano , Actitud del Personal de Salud , Estudios Transversales , Femenino , Encuestas de Atención de la Salud , Humanos , Masculino , Errores de Medicación/efectos adversos , Persona de Mediana Edad , Alta del Paciente , Encuestas y Cuestionarios , Suiza , Factores de TiempoRESUMEN
This study aimed to explore women's desire for information about mammography screening in a population where overly optimistic perceptions of mammography screening were common. A self-administered questionnaire was completed by 2305 women aged 50-69 years, residents of Geneva, Switzerland. The questionnaire assessed the respondents' wish to receive information (detailed, general or none) about seven aspects of mammography screening: personal risk of breast cancer, prevention of breast cancer, benefits of mammography screening, limitations, minor inconveniences, more important problems, why some people oppose screening. The seven items formed a unidimensional scale (Cronbach's alpha=0.91). Women differed considerably in their stated desire for detailed or general information. For instance, whereas 14% wanted detailed information on all items and 36% general information on all items, 39% were not interested in detailed information on the limits and adverse consequences of screening. In multivariate analysis, some women's characteristics were associated with higher scores of desire for information, but little variance was explained (adjusted R=0.05). In conclusion, many women currently decline information about mammography screening that is deemed relevant by public health authorities. This may lead to poorly informed choices in an important area of prevention.
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Neoplasias de la Mama/prevención & control , Mamografía/psicología , Tamizaje Masivo , Factores de Edad , Anciano , Actitud Frente a la Salud , Estudios Transversales , Escolaridad , Femenino , Conocimientos, Actitudes y Práctica en Salud , Humanos , Persona de Mediana Edad , Análisis Multivariante , Probabilidad , Psicología , Medición de Riesgo , Encuestas y Cuestionarios , SuizaRESUMEN
A 62-year-old woman with severe osteoporosis experienced pulmonary embolism by polymethylmethacrylate after percutaneous vertebroplasty. The patient immediately developed respiratory and cardiac distress, and a computed tomographic scan revealed the presence of cement in the pulmonary circulation. Proper techniques can minimize the risk of pulmonary embolism during percutaneous vertebroplasty: adequate preparation of cement and fluoroscopy during the procedure are recommended.
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Cementos para Huesos/efectos adversos , Vértebras Lumbares/cirugía , Polimetil Metacrilato/efectos adversos , Embolia Pulmonar/etiología , Femenino , Cardiopatías/etiología , Humanos , Persona de Mediana Edad , Procedimientos Ortopédicos , Osteoporosis/complicaciones , Embolia Pulmonar/diagnóstico por imagen , Síndrome de Dificultad Respiratoria/etiología , Tomografía Computarizada por Rayos XRESUMEN
This study was designed to experimentally evaluate the optimal X-ray energy for increasing the radiation energy absorbed in tumours loaded with iodinated compounds, using the photoelectric effect. SQ20B human cells were irradiated with synchrotron monochromatic beam tuned at 32.8, 33.5, 50 and 70 keV. Two cell treatments were compared to the control: cells suspended in 10 mg ml(-1) of iodine radiological contrast agent or cells pre-exposed with 10 microM of iodo-desoxyuridine (IUdR) for 48 h. Our radiobiological end point was clonogenic cell survival. Cells irradiated with both iodine compounds exhibited a radiation sensitisation enhancement. Moreover, it was energy dependent, with a maximum at 50 keV. At this energy, the sensitisation calculated at 10% survival was equal to 2.03 for cells suspended in iodinated contrast agent and 2.60 for IUdR. Cells pretreated with IUdR had higher sensitisation factors over the energy range than for those suspended in iodine contrast agent. Also, their survival curves presented no shoulder, suggesting complex lethal damages from Auger electrons. Our results confirm the existence of the 50 keV energy optimum for a binary therapeutic irradiation based on the presence of stable iodine in tumours and an external irradiation. Monochromatic synchrotron radiotherapy concept is hence proposed for increasing the differential effect between healthy and cancerous tissue irradiation.
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Carcinoma de Células Escamosas/patología , Neoplasias de Cabeza y Cuello/patología , Idoxuridina/farmacología , Yodo/farmacocinética , Inhibidores de la Síntesis del Ácido Nucleico/farmacología , Fármacos Sensibilizantes a Radiaciones/farmacología , Terapia por Rayos X/métodos , Muerte Celular , Supervivencia Celular , Medios de Contraste/farmacocinética , Humanos , Idoxuridina/farmacocinética , Yodo/farmacología , Inhibidores de la Síntesis del Ácido Nucleico/farmacocinética , Tolerancia a Radiación , Fármacos Sensibilizantes a Radiaciones/farmacocinética , Células Tumorales CultivadasRESUMEN
In this paper we describe the results of experiments using synchrotron radiation to trigger the Auger effect in living human cancer cells treated with a widely used chemotherapy drug: cis-diamminedichloroplatinum (II) (cisplatin). The experiments were carried out at the ID17 beamline of the European Synchrotron Radiation Facility, which produces a high-fluence monochromatic beam that is adjustable from 20 to 80 keV. Cisplatin was chosen as the carrier of platinum atoms in the cells because of its alkylating-like activity and the irradiation was done with monochromatic beams above and below the platinum K-shell edge (78.39 keV). Cell survival curves were comparable with those obtained for the same cells under conventional irradiation conditions. At a low dose of cisplatin (0.1 microM, 48 h), no difference was seen in survival when the cells were irradiated above and below the K-shell edge of platinum. Higher cisplatin concentrations were investigated to enhance the cellular platinum content. The results with 1 microM cisplatin for 12 h showed no difference when the cells were irradiated with beams above or below the platinum K-shell edge with the exception of the higher cell death resulting from drug toxicity. The intracellular content of platinum was significant, as measured macroscopically by inductively coupled plasma mass spectrometry. Its subcellular localization and particularly its presence in the cell nucleus were verified by microscopic synchrotron X-ray fluorescence. This was the first known attempt at K-shell edge photon activation of stable platinum in living cells with a platinum complex used for chemotherapy. Its evident toxicity in these cells leads us to put forth the hypothesis that cisplatin toxicity can mask the enhancement of cell death induced by the irradiation above the K-shell edge. However, K-shell edge photon activation of stable elements provides a powerful technique for the understanding of the biological effects of Auger processes. Further avenues of development are discussed.
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Muerte Celular , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Cisplatino/farmacología , Aceleradores de Partículas/instrumentación , Platino (Metal)/farmacología , Fármacos Sensibilizantes a Radiaciones/farmacología , Rayos X , Calibración , Ciclo Celular , Línea Celular , Ensayo de Unidades Formadoras de Colonias , Relación Dosis-Respuesta en la Radiación , Citometría de Flujo , Neoplasias de Cabeza y Cuello/radioterapia , Humanos , Fotones , Células Tumorales CultivadasRESUMEN
We investigated the performance of monochromatic computed tomography for the quantification of contrast agent concentrations. Two subtraction methods (K-edge subtraction and temporal subtraction) were evaluated and compared theoretically and experimentally in terms of detection limit, precision and accuracy. Measurements were performed using synchrotron x-rays with Lucite phantoms (10 cm and 17.5 cm in diameter) containing iodine or gadolinium solutions ranging from 50 microg ml(-1) to 5 mg ml(-1). The experiments were carried out using monochromators developed at the European Synchrotron Radiation Facility (ESRF) medical beamline. The phantoms were imaged either above and below the contrast agent K-edge, or before and after the addition of the contrast agent. Both methods gave comparable performance for phantoms less than 10 cm in diameter. For large phantoms, equivalent to a human head, the temporal subtraction is more suitable for detecting elements such as iodine, keeping a reasonable x-ray dose delivered to the phantom. A good agreement was obtained between analytical calculations, simulations and measurements. The beam harmonic content was taken into account in the simulations. It explains the performance degradation with high contrast agent concentrations. The temporal subtraction technique has the advantage of energy tunability and is well suited for imaging elements, such as iodine or gadolinium, in highly absorbing samples. For technical reasons, the K-edge method is preferable when the imaged organ is moving since the two measurements can be performed simultaneously, which is mandatory for obtaining a good subtraction.
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Medios de Contraste/farmacología , Tomografía Computarizada por Rayos X/métodos , Rayos X , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/metabolismo , Relación Dosis-Respuesta a Droga , Gadolinio/farmacología , Humanos , Yodo/farmacología , Distribución Normal , Fantasmas de Imagen , Fotones , Radiometría , Factores de TiempoAsunto(s)
Carcinoma de Células Escamosas/radioterapia , Medios de Contraste/farmacología , Yopamidol/análogos & derivados , Yopamidol/farmacología , Ácido Yoxáglico/farmacología , Neoplasias Laríngeas/radioterapia , Fármacos Sensibilizantes a Radiaciones/farmacología , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Relación Dosis-Respuesta a Droga , Humanos , Fotones , Sincrotrones , Tomografía Computarizada por Rayos X , Células Tumorales Cultivadas/efectos de la radiaciónRESUMEN
This study assessed predictions of the Transtheoretical Model (TTM) of behaviour change applied to mammography screening in a random sample of 909 Swiss women aged 40-80 years. We examined stages of mammography adoption, positive and negative attitudes toward screening (pros, cons and decisional balance), and additional predisposing, enabling and reinforcing characteristics. The stage of mammography adoption was defined for 827 women, of whom 46.9% reported on-schedule screening (action 10.2%, maintenance 29.7%, relapse risk 7.0%) and 53% did not (precontemplation 23.1%, contemplation 13.5%, relapse 16.4%). Independent factors associated with more advanced stages (from precontemplation to maintenance) were high pros, low cons, belief that mammography screening is recommended every 2 years, high objective risk of breast cancer, being married and higher income. Independent correlates of stage regression (from action/maintenance to relapse) were high cons, belief that mammography screening is recommended every 4 years or not at all and not being married. Perceived utility of an organised screening programme and reluctance to pay for a mammogram were independently associated with only certain transitions between stages of adoption. Our results confirm the applicability of the TTM to mammography screening in a European context. They also suggest that constructs other than pros and cons may be useful in predicting mammography use.
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Neoplasias de la Mama/diagnóstico por imagen , Mamografía/psicología , Tamizaje Masivo/psicología , Aceptación de la Atención de Salud/psicología , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias de la Mama/psicología , Toma de Decisiones , Femenino , Conductas Relacionadas con la Salud , Humanos , Mamografía/estadística & datos numéricos , Tamizaje Masivo/estadística & datos numéricos , Persona de Mediana Edad , Modelos Psicológicos , Análisis Multivariante , Medición de Riesgo , SuizaRESUMEN
The application of synchrotron radiation in medical research has become a mature field of research at synchrotron facilities worldwide. In the relatively short time that synchrotrons have been available to the scientific community, their characteristic beams of UV and X-ray radiation have been applied to virtually all areas of medical science which use ionizing radiation. The ability to tune intense monochromatic beams over wide energy ranges differentiates these sources from standard clinical and research tools. At the European Synchrotron Radiation Facility (Grenoble, France), a major research facility is operational on an advanced wiggler radiation beamport, ID17. The beamport is designed to carry out a broad range of research ranging from cell radiation biology to in vivo human studies. Medical imaging programs at ID17 include transvenous coronary angiography, computed tomography, mammography and bronchography. In addition, a major research program on microbeam radiation therapy is progressing. This paper will present a very brief overview of the beamline and the imaging and therapy programs.
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Sincrotrones/instrumentación , Animales , Angiografía Coronaria/instrumentación , Europa (Continente) , Humanos , Radioterapia de Alta Energía/instrumentación , Investigación , Tomografía Computarizada por Rayos X/instrumentación , Difracción de Rayos X/instrumentaciónRESUMEN
We present in this paper two imaging techniques using contrast agents assessed with in vivo experiments. Both methods are based on the same physical principle, and were implemented at the European Synchrotron Radiation Facility medical beamline. The first one is intravenous coronary angiography using synchrotron radiation X-rays. This imaging technique has been planned for human studies in the near future. We describe the first experiments that were carried out with pigs at the ESRF. The second imaging mode is computed tomography using synchrotron radiation on rats bearing brain tumors. Owing to synchrotron radiation physical properties, these new imaging methods provide additional information compared to conventional techniques. After infusion of the contrast agent, it is possible to derive from the images the concentration of the contrast agent in the tumor area for the computed tomography and in any visible vessel for the angiography method.
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Angiografía Coronaria/métodos , Sincrotrones , Tomografía Computarizada por Rayos X/métodos , Animales , Neoplasias Encefálicas/diagnóstico por imagen , Medios de Contraste , Angiografía Coronaria/instrumentación , Europa (Continente) , Gadolinio , Glioma/diagnóstico por imagen , Humanos , Yodo , Ratas , Porcinos , Sincrotrones/instrumentación , Tomografía Computarizada por Rayos X/instrumentaciónRESUMEN
The first operation of the European Synchrotron Radiation Facility (ESRF) medical beamline is reported in this paper. The goal of the angiography project is to develop a reduced risk imaging technique, which can be used to follow up patients after coronary intervention. After the intravenous injection of a contrast agent (iodine) two images are produced with monochromatic beams, bracketing the iodine K-edge. The logarithmic subtraction of the two measurements results in an iodine enhanced image, which can be precisely quantified. A research protocol has been designed to evaluate the performances of this method in comparison with the conventional technique. Patients included in the protocol have previously undergone angioplasty. If a re-stenosis is suspected, the patient is imaged both at the ESRF and at the hospital with the conventional technique, within the next few days. This paper reports the results obtained with the first patients. To date, eight patients have been imaged and excellent image quality was obtained.
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Angiografía Coronaria/instrumentación , Angiografía Coronaria/métodos , Sincrotrones , Angioplastia Coronaria con Balón/instrumentación , Angioplastia Coronaria con Balón/métodos , Europa (Continente) , Francia , HumanosRESUMEN
The purpose of this work was to demonstrate the feasibility of a new imaging technique called synchrotron radiation computed tomography (SRCT). This technique leads to a direct assessment of the in vivo concentration of an iodine- or gadolinium-labeled compound. Rats bearing C6 glioma were imaged by MRI prior to the SRCT experiment. The SRCT experiments were performed after a 1.3 g I/kg (n = 5) or a 0.4 g Gd/kg (n = 5) injection. Finally, brains were sampled for histology. The SRCT images exhibited contrast enhancement at the tumor location. Ten minutes after injection, iodine and gadolinium tissular concentrations were equal to 0.80 ( +/- 0.40) mg/cm3 and 0.50 ( +/- 0.10) mg/cm3, respectively in the peripheral area of the tumor (respective background value: 0.20 +/- 0.02 to 0.10 +/- 0.01). Correlation to MRI and histology revealed that the contrast uptake occurred in the most vascularized area of the tumor. The present study summarizes the feasibility of in vivo SRCT to obtain quantitative information about iodine and gadolinium-labeled compounds. Beyond brain tumor pathology, the SRCT appears as a complementary approach to MRI and CT, for studying iodine- and gadolinium-labeled compounds by the direct achievement of the tissular concentration value in the tissue.
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Neoplasias Encefálicas/diagnóstico , Medios de Contraste , Gadolinio , Glioma/diagnóstico , Ácido Yoxáglico , Meglumina , Compuestos Organometálicos , Sincrotrones , Tomografía Computarizada por Rayos X , Animales , Estudios de Factibilidad , Femenino , Ratas , Ratas Wistar , Células Tumorales CultivadasRESUMEN
A fixed-exit monochromator has been constructed for computed tomography (CT) studies at the Medical Beamline of the European Synchrotron Radiation Facility. A non-dispersive pair of bent Laue-type crystals is used, and the first crystal is water-cooled. The monochromator operates at energies from 18 to 90 keV, and the maximum width of the beam is 150 mm. The performance of the monochromator is studied with respect to the beam intensity and energy distributions, and a close agreement is found between the calculated and experimental results. The intensity is between 10(9) and 10(10) photons s(-1) mm(-2) under typical operating conditions. The harmonic content of a 25 keV beam is about 30% at the minimum wiggler gap of 25 mm (field 1.57 T) and decreases by an order of magnitude when the gap is increased to 60 mm (field 0.62 T). The experimental set-up for CT studies includes dose monitors, goniometers and translation stages for positioning and scanning the object, and a 432-element linear-array Ge detector. Examples from phantom studies and in vivo animal experiments are shown to illustrate the spatial resolution and contrast of the reconstructed images.