Paramètres biologiques de réponse tardive des tissus sains aux rayonnements ionisants

By their irreversible nature and their impact on the quality of life, late side effects of normal tissues are the main limiting factors of radiotherapy. Irradiation is the source of many biological disorders leading to destruction of stem cells, vascular damage, and the gradual development of interstitial fibrosis, which worsens with time. Among one population treated with similar techniques of radiotherapy, some patients had increased toxicity suggesting the existence of different in dividual radiosensitivity. Predictive tools, based on the study of lymphocytes apoptosis and the modification of certain genes involved in the response to irradiation, are being developed to identify these radiosensitive patients. It has been therefore shown that low percentage of radiation-induced CD8 lymphocyte apoptosis in vitro correlated with severe radiation-induced late side-effects and corresponded to more than 4 type of SNPs (single nucleotide polymorphisms) in candidate genes (ATM, SOD2, TGFB1, XRCC1 and XRCC3).     

Mesure de l’exposition externe du personnel du service de médecine nucléaire de l’hôpital Ibn Sina de Rabat au cours de la manipulation des radiopharmaceutiques

The nuclear medicine department of Ibn Sina hospital was created in 1965. Its first location was in radiology department, and then it was transferred in 1977 to the old emergency unit. The conception was not originally dedicated for a nuclear medicine department. To reassure the medical staff about their exposition during radiopharmaceutical manipulation, a dosimetric study was performed in collaboration with the National center of radiation protection (CNRP). Dosimetric monitoring was conducted for 3 months with the use of passive thermoluminescent dosimeters, (Harshow, 6600 plus), covering all categories of staff. The administration of 153 Samarium has been also studied. Other cases of people concerned our study: a pregnant woman doctor, whose exposure of the unborn child must be reduced as much as possible, and a woman from a private company, working occasionally in the department. To control the conditions imposed on all activities requiring exposure to ionizing radiation, we evaluated the dose at the extremities of operators with the use of ring dosimeters (Harshow 6600 plus) and the dose on the ambient environment of staff. This experiment has shown exposure levels below legal limits, without been negligible for some workstations. Technicians equivalent doses results justify the wearing of dosimeter rings as a complementary dosimeter in nuclear medicine department. Finally, monitoring ambient dosimetry showed that the environment measurements are in keeping with national and international norms. The Medical staff was very interested by this study, which demonstrates that radiation protection standards are respected through awareness, basic training, continuing education and information. The first author is particularly involved in the practical procedures in order to respect radiation protection recommendations for restraining staff annual chest and extremities dosimetry figures within regulations values.     

Place de l’imagerie dans l’évaluation de l’efficacité des traitements dans le cancer du sein

This paper describes, from the current literature, the role of various imaging methods to assess the response to therapy in breast cancer. Two different clinical situations are considered: neoadjuvant chemotherapy of locally advanced breast cancer and the metastastic breast cancer. Significant clinical data are available for three criteria: the volume of the tumour, the uptake of fluorodeoxyglucose using PET and the perfusion of the tumor evaluated either by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) or by PET using ¹⁵O water. ¹⁸F FDG PET allows prediction of the response after one or two cycles of neoadjuvant chemotherapy. New approaches will offer opportunities to refine the role of imaging in monitoring the response to chemotherapy. PET using thymidine as biomarker is promising in assessing the tissular proliferation. Estrogen analogs could be used to predict hormonally responsive breast cancer. Many other approaches, although less developed, might offer new insights in the response to therapy of breast cancer like magnetic resonance spectroscopy or optical imaging of hemoglobin oxygenation. Imaging also offers potential of monitoring the down-regulation of specialized receptors of the cell membrane in response to treatment: the most studied receptor in preclinical model has been the human epidermal growth factor receptor type 2 (HER2). Integrin, a family of cell adhesion receptor, is also an important target for imaging. Apoptosis, multidrug resistance and hypoxia can also be studied using appropriate biomarkers. To allow reliable multicenter trials of new drugs, these different imaging approaches still require an improved standardization of image acquisition and processing.     

Armes de chasse dans l’Épipaléolithique du Caucase du Nord

The article is devoted to the traceological study of points and geometric microliths that are characteristic of the Epipaleolithic sites of the northwestern Caucasus and the Elbrus region. The regularities between the type of stone tools and their functional use are analyzed. Composite hunting weapons were effectively used in hunting a variety of ungulate herd animals. The composition of faunal assemblages largely depended of climatic and landscape conditions of the sites in different periods of the Late Glacial period: from the Oldest Dryas to the Pleistocene–Holocene transition. The proximity of lithic industries within a vast region in the North Caucasus, similar shapes of projectiles and lithic inserts into composite hunting weapons could be associated with active human movements, which are confirmed by the transportation of obsidian from the Elbrus region to the northwestern Caucasus and the transportation of high-quality flint from the west to the Elbrus region in the north-central Caucasus.     

Mesure de l’exposition externe au cours de la détection peropératoire. Expérience du service de médecine nucléaire de l’hôpital Ibn Sina

Nationally, the department of nuclear medicine, Ibn Sina Hospital is the first service that started with the technique of isotopic labeling for the treatment of osteoid osteoma and identification of sentinel lymph node. However, the operating room is a place where the staff is not familiar with the handling of radioactive substances. The intraoperative detection in these places leads the staff working there to ask some questions related to radiation safety. In this work, we have implemented the radiation protection aspects of these acts by the measurement of external exposure of personnel involved and we confirmed that the dosimetric measurements are negligible.     

L’évaluation des nouvelles technologies en santé : un nouveau besoin,l’évaluation de l’adaptation à l’usage

In healthcare, technologies have a critical role in diagnostic, treatment and monitoring of the patients, either in hospitals settings or at home. But in order to be used in clinical routine, their assessment does not always comply with strict scientific criteria. In some situations, these technologies can also turn out useless, too costly or dangerous when integrated without precaution in the healthcare professional environment. In France, to address this issue, the Ministry of Health and the National Agency for Research in Medicine have installed new “Innovative Technologies” (IT) modules attached to existing Centres for Clinical Research (CRC). Eight CRC-IT (in short, CIT) have been accredited in different technological domains. They may support and secure the dissemination of promising IT applications in healthcare by assessing (i) the actual benefit for the patients, or medical service rendered, (ii) the potential drawbacks and (iii) the anticipated Return On Investment for the healthcare system. The procedures used to evaluate other healthcare innovations such as new drugs cannot be applied for the evaluation of innovative technologies. CIT also have to adapt their methodology to the type of device and domain. Besides the impact on the patient or public health, CIT are able to analyze the impact of innovative technologies on the quality of care and on their use by professionals.     

Évaluation de l’irradiation additionnelle des patients de médecine nucléaire en imagerie hybride TEMP/TDM

One hundred and ten consecutive patients and 130 SPECT/CT examinations were involved in this retrospective study that focused on the evaluation of the excess of dose contributed by the CT to the patient during the SPECT/CT explorations, for routine examinations in nuclear medicine. The average age of patients was 53 years. In this study, it appeared that irradiation induced by a low dose CT combined with a SPECT is low compared to that of a diagnostic CT. The main risk on patients is the occurrence of radiation-induced cancer. In our study, this increased risk induced by the additional CT with low dose settings in line with SPECT examination, is not significant and does not exceed 0.026%. By weighing the diagnostic value of SPECT/CT examination with that of a stand-alone SPECT examination dosimetric “incremental cost” is justified because of its direct clinical benefit conveyed to the patient.     

Évaluation de la perfusion et de la fonction contractile du myocarde à l’aide de l’analyse de Karhunen-Loeve en tomographie d’émission monophotonique myocardique synchronisée à l’ECG

GoalWe evaluated the diagnostic performance of the Karhunen–Loeve transform applied to myocardial gated SPECT. The previous studies showed that KLT images characterize myocardial perfusion (KL0) and contractile function (KL1).Method and material99mTc-gSPECT studies were performed in 101 patients (121 acquisitions) with suspected or known coronary artery disease. The images were evaluated using a five-point scoring system dividing the left ventricle into 11 segments. We compared the scores obtained by this semi-quantitative visual analysis of gSPECT and KLT images.Results and discussionThe agreement for perfusion and thickening scores was 94 and 95% respectively. Quantitative evaluation of KL0 and KL1 images by univariate and multivariate analysis was performed in the left ventricular ROI. Discriminant analysis characterized the acquisitions as normal or pathologic with a sensitivity of 95% and a specificity of 96% and positive and negative predictive values of 96 and 95%. These selection criteria were tested prospectively in 52 patients with similar results. KLT generates a synthesis of left ventricular perfusion and kinetics. It facilitates discrimination between normal and pathological acquisitions with high predictive values.     

Évaluation de la TEP au 18F-FDG dans l’exploration de la récidive des carcinomes colorectaux

PurposeThe aim of the study was to evaluate the diagnostic performance, the prognosis factors and the therapeutic impact of 18F-FDG positron emission tomography (FDG-PET) in the detection of recurrent colorectal cancers.MethodsSixty PET/CT with 18F-FDG and CT were performed in 52 patients, at the Paul Papin cancer center between 2003 and 2005, following suspicion of colorectal cancer relapse. The FDG-PET impact on the clinical management was studied by examination of multidisciplinary concertations results. Survival analysis were realized with a mean follow up of 2.2 years.ResultsRecurrence was confirmed for 50 explorations by histologic (n = 32), radiologic (n = 14) or clinical (n = 4) findings. Twenty patients died during the time of the study. On a patient based analysis, FDG-PET sensitivity, specificity and overall accuracy were 90, 90, 90% respectively compared with 74, 50 and 70% for CT. FDG-PET changed the clinical management in 18 cases (30%). A positive FDG-PET signal, more than one hepatic lesion, more than two lymph node lesions detected on FDG-PET and more than two hepatic lesions on CT were characterized as bad prognostic factors for survival. Multivariate analysis showed that the only independent bad prognostic factor was the FDG-PET detection of more than two liver lesions.ConclusionThese results confirmed the important impact of FDG-PET in the clinical management of patients with a suspected recurrence of colorectal cancer.