[Limits of dose constraint definition for organs at risk specific to stereotactic radiotherapy]. / Limites de la définition des contraintes de dose pour les organes à risque spécifiques à la radiothérapie stéréotaxique.

Stereotactic radiotherapy is a very hypofractionated radiotherapy (>7.5Gy per fraction), and therefore is more likely to induce late toxicities than conventional normofractionated irradiations. The present study examines four frequent and potentially serious late toxicities: brain radionecrosis, radiation pneumonitis, radiation myelitis, and radiation-induced pelvic toxicities. The critical review focuses on the toxicity scales, the definition of the dose constrained volume, the dosimetric parameters, and the non-dosimetric risk factors. The most commonly used toxicity scales remain: RTOG/EORTC or common terminology criteria for adverse events (CTCAE). The definition of organ-at-risk volume requiring protection is often controversial, which limits the comparability of studies and the possibility of accurate dose constraints. Nevertheless, for the brain, whatever the indication (arteriovenous malformation, benign tumor, metastasis of solid tumors...), the association between the volume of brain receiving 12Gy (V12Gy) and the risk of cerebral radionecrosis is well established for both single and multi-fraction stereotactic irradiation. For the lung, the average dose received by both lungs and the V20 seem to correlate well with the risk of radiation-induced pneumonitis. For the spinal cord, the maximum dose is the most consensual parameter. Clinical trial protocols are useful for nonconsensual dose constraints. Non-dosimetric risk factors should be considered when validating the treatment plan.

Cognitive function and 99mTc-ECD brain SPECT are significantly correlated in patients with primary Sjogren syndrome: a case-control study.

OBJECTIVES: To assess subclinical central nervous system (CNS) involvement in primary Sjögren syndrome (pSS), by comparing standard brain MRI, in-depth neuropsychological testing and (99m)Tc-ECD brain single-photon emission computed tomography (SPECT) of patients with pSS with matched controls. METHODS: 10 women (<55 years old), with pSS defined using European-American criteria, presence of anti-SSA and/or anti-SSB antibodies and no history of neurological involvement were prospectively investigated, and compared with 10 age- and sex-matched controls. All subjects underwent, within 1 month, brain MRI, neuropsychological testing, including overall evaluation and focal cognitive function assessment, and (99m)Tc-ECD brain SPECT. RESULTS: (99m)Tc-ECD brain SPECT abnormalities were significantly more common in patients with pSS (10/10) than controls (2/10; p<0.05). Cognitive dysfunctions, mainly expressed as executive and visuospatial disorders, were also significantly more common in patients with pSS (8/10) than controls (0/10; p<0.01). Notably, between-group comparisons enabled a significant correlation to be established between neuropsychological assessment and (99m)Tc-ECD brain SPECT abnormalities in patients with pSS (r(s) = 0.49, p<0.01). MRI abnormalities in patients and controls did not differ significantly. CONCLUSIONS: Neuropsychological testing and (99m)Tc-ECD brain SPECT seem to be the most sensitive tools to detect subclinical CNS dysfunction in pSS. The strong correlation between cortical hypoperfusion in (99m)Tc-ECD brain SPECT and cognitive dysfunction suggests an organic aetiology of CNS dysfunction in pSS. These data should be confirmed in a larger study.

[MRI features of spinal neurosarcoidosis associed with cervical spondylosis]. / Myélopathie sarcoïdosique associée à un canal cervical rétréci : aspects IRM.

INTRODUCTION: Spinal neurosarcoidosis is rare and exceptionally inaugural. OBSERVATION: A 49-year-old African woman developed a progressive left Brown-Sequard syndrome. Magnetic resonance imaging (MRI) scans of the cervical spinal cord revealed an intramedullary lesion from C2 to T1 with intense pial enhancement after administration of contrast material associated with cervical spondylosis. The diagnostic of sarcoidosis was confirmed by liver biopsy which demonstrated noncaseating granulomas. CONCLUSIONS: MRI features of spinal neurosarcoidosis were reviewed by the authors with focus on differential diagnosis.

Independent 6D quality assurance of stereotactic radiotherapy repositioning on linacs.

PURPOSE: A high level of accuracy while positioning the patient is mandatory for frameless stereotactic radiotherapy (SRT), as large doses in multiple fractions can be delivered near organs at risk. The objective of this study is to propose an end-to-end quality assurance method to verify that submillimetre alignment can be achieved with stereotactic conventional linacs. METHODS: We used a TrueBeam® linear accelerator equipped with a 6DOF robotic couch. The "ISO Cube" phantom was used with a homemade stand designed to generate known translational and rotational offsets. A reference CT scan was performed with straight alignment of the phantom. The procedure introduced 1.6° angular offset for the couch pitch and roll, at various gantry angles. The couch base was also moved between 0° and 270°. We compared the results with the daily machine performance check tests (MPC, Varian). RESULTS: The mean isocentre size, MV and kV imager offsets were found to agree to within 0.1mm, 0.1mm and 0.3mm respectively, and were in close agreement between the methods. For a total four months data collection period, the mean deviation between requested and measured 6DOF couch shifts was 0.6mm and 0.2°. Errors on field size were smaller than 1mm for 97.7% of the 324 data points. CONCLUSION: Results demonstrate that the linac equipped with a 6DOF robotic positioner and CBCT imaging satisfies requirements for SRT. Our methodology, based on a modified Winston-Lutz quality control, allowed us to quantitatively assess end-to-end accuracy of a linac in order to safely deliver SRT.

[Dosimetric impact of the 2D motion of a platform simulating breathing during a dynamic mode treatment]. / Impact dosimétrique du mouvement 2D d'une plateforme simulant la respiration lors d'un traitement en mode dynamique.

Breathing-adapted techniques in external radiotherapy lead to the improvement of the taken into account of the tumour motion during the patient treatment. Indeed, this motion involves dosimetric uncertainties, in particular during a dynamic treatment (intensity-modulated radiation therapy, dynamic wedge...). As tumoral movement is complex and is carried out in various directions of space, a dynamic platform moving in one or two plans was conceived. This article approaches the technical aspects of design and functioning of this prototype. A study of the dosimetric effects of the respiratory movement on one and two plans during a dynamic treatment without gating will be presented. Films were irradiated while varying the rates with wedged fields at various speeds. The penumbra of beams were compared with the static case and appeared twice broader in the majority of the cases. The results highlighted the contributions of the longitudinal and the axial components of the motion on the form of the dose distribution. These results were completed with gamma index measurements to determine an internal margin. Moreover, this platform proves to be a promising tool for breathing-adapted treatment, in particularly to test the synchronisation of RPM system in fluoroscopic mode in board imaging system.

[MR and CT features of craniocervical junction tuberculosis: a report of 5 cases]. / Caractéristiques IRM et TDM de la tuberculose de la jonction crânio-vertébrale: à propos de 5 cas.

Tuberculosis of the craniocervical junction is rare but may cause significant complications with severe sequelae due to the nearby presence of important neurovascular structures. The CT and MR features of 5 cases are presented with correlation with reports from the literature. The differential diagnosis is reviewed.

[Technical aspects and indications of extracranial stereotactic radiotherapy]. / Place de la radiothérapie stéréotaxique extracrânienne dans la prise en charge des patients atteints de cancer.

Extracranial stereotactic radiotherapy has developed considerably in recent years and is now an important part of the therapeutic alternatives to be offered to patients with cancer. It offers opportunities that have progressively led physicians to reconsider the therapeutic strategy, for example in the case of local recurrence in irradiated territory or oligometastatic disease. The literature on the subject is rich but, yet, there is no real consensus on therapeutic indications. This is largely due to the lack of prospective, randomized studies that have evaluated this technique with sufficient recoil. We propose a review of the literature on the technical aspects and indications of extracranial stereotactic radiotherapy.

MR diffusion tensor imaging and fiber tracking in spinal cord arteriovenous malformations: a preliminary study.

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) of the spinal cord in patients harboring spinal arteriovenous malformations (AVMs) was carried out to evaluate the feasibility of this new technique to determine the displacement of the spinal cord tracts and to correlate morphologic and functional DTI data (fractional anisotropy [FA] and apparent diffusion coefficient [ADC]) with the clinical symptoms. MATERIALS AND METHODS: Nine patients with spinal cord AVMs were investigated at 1.5T using a sagittal spin-echo single-shot echo-planar generalized autocalibrating partially parallel acquisition diffusion-weighted imaging sequence. ADC and FA maps were computed in different regions of interest (both above and below the nidus), and tractography was used to visualize the course of the tracts. The data were correlated with the clinical symptoms and compared with 12 healthy control subjects. RESULTS: At the level of the nidus, tracts were normal, shifted, separated, or interrupted but not intermingled with the nidus. Interruption of the tracts was coherent with the clinical symptoms. In patients with severe neurologic deficits, FA values caudal to the nidus showed a reduced anisotropy consistent with loss of white matter tracts. CONCLUSIONS: We demonstrate that AVMs may interrupt, displace, or separate the fiber tracts and that clinical symptoms may be reflected by the quantitative FA results and the morphologic loss of fibers distant to the lesion. DTI with fiber tracking offers a novel approach to image spinal cord AVMs and may open a window to understand the complex pathophysiology of these lesions.

[Practical recommendations for breathing-adapted radiotherapy]. / Bonnes pratiques pour la radiothérapie asservie à la respiration.

Respiration-gated radiotherapy offers a significant potential for improvement in the irradiation of tumor sites affected by respiratory motion such as lung, breast and liver tumors. An increased conformality of irradiation fields leading to decreased complications rates of organs at risk (lung, heart...) is expected. Respiratory gating is in line with the need for improved precision required by radiotherapy techniques such as 3D conformal radiotherapy or intensity modulated radiotherapy. Reduction of respiratory motion can be achieved by using either breath-hold techniques or respiration synchronized gating techniques. Breath-hold techniques can be achieved with active techniques, in which airflow of the patient is temporarily blocked by a valve, or passive techniques, in which the patient voluntarily holds his/her breath. Synchronized gating techniques use external devices to predict the phase of the respiration cycle while the patient breaths freely. This work summarizes the different experiences of the centers of the STIC 2003 project. It describes the different techniques, gives an overview of the literature and proposes a practice based on our experience.

[Listeria monocytogenes encephalitis revealed by left progressive hemiparesis]. / Hémiparésie d'installation progressive révélant une encéphalite à listéria monocytogènes.

INTRODUCTION: Central nervous system listeriosis is a diagnostic and therapeutic challenge for the clinician. CASE REPORT: We report the case of a 66-year-old woman who was admitted for a left progressive hemiparesis associated with headaches. She was treated for one year by immunosuppressive drugs for vulgaris pemphigus. At the time of admission, examination revealed left hemiparesis without fever, and a computed tomography brain scan demonstrated a focal lesion in the right frontal lobe. Blood analyses were normal. Two days after, she suddenly developed fever (40 degrees C), and aggravation of her motor deficit followed by partial motor seizures. The cerebrospinal fluid was normal. Treatment with amoxicillin (3g IV q6h), cefotaxim, gentamycin (120mg IV q12h) and aciclovir was started empirically. The brain MRI without gadolinium displayed infiltrative lesions in the right hemisphere and in the mildbrain. The blood culture grew Listeria monocytogenes. The antimicrobial regimen was changed to amoxicillin for seven weeks and gentamicin for the first ten days. Four days after beginning the antimicrobial regimen, the brain MRI with gadolinium displayed several abscesses measuring less than one cm diameter. The clinical and imaging outcome excellent. CONCLUSION: Meningitis is by far the most central nervous system listeriosis. In our patient, the diagnosis of listeria monocytogenes encephalitis was established on the basis of positive blood cultures, as such patients do not have sterile cerebrospinal fluid.

Equivalent uniform dose concept evaluated by theoretical dose volume histograms for thoracic irradiation.

BACKGROUND AND PURPOSE: The goal of our study was to quantify the limits of the EUD models for use in score functions in inverse planning software, and for clinical application. MATERIALS AND METHODS: We focused on oesophagus cancer irradiation. Our evaluation was based on theoretical dose volume histograms (DVH), and we analyzed them using volumetric and linear quadratic EUD models, average and maximum dose concepts, the linear quadratic model and the differential area between each DVH. RESULTS: We evaluated our models using theoretical and more complex DVHs for the above regions of interest. We studied three types of DVH for the target volume: the first followed the ICRU dose homogeneity recommendations; the second was built out of the first requirements and the same average dose was built in for all cases; the third was truncated by a small dose hole. We also built theoretical DVHs for the organs at risk, in order to evaluate the limits of, and the ways to use both EUD(1) and EUD/LQ models, comparing them to the traditional ways of scoring a treatment plan. For each volume of interest we built theoretical treatment plans with differences in the fractionation. CONCLUSION: We concluded that both volumetric and linear quadratic EUDs should be used. Volumetric EUD(1) takes into account neither hot-cold spot compensation nor the differences in fractionation, but it is more sensitive to the increase of the irradiated volume. With linear quadratic EUD/LQ, a volumetric analysis of fractionation variation effort can be performed.

Esophageal cancer: determination of internal target volume for conformal radiotherapy.

BACKGROUND AND PURPOSE: To evaluate esophageal tumor and OAR movement during the respiratory cycle in order to obtain optimal values for ITV and PRV. To correlate tumor motion with chest wall displacement - information of value in the free-breathing gating system. MATERIAL AND METHOD: Inclusion criteria were: histologically proven squamous-cell carcinoma (SCC) or adenocarcinoma at stage T3 - T4 NX or TX N1 M0 according to the UICC 1997 classification. Two spiral scans were performed with breath-hold respiration under spirometric control: one at end expiration (EBH) and the other at end inspiration (IBH). Displacements between exhalation and inhalation were calculated according to ICRU report 42 recommendations. For the correlation study, CT-scan acquisition was performed at the isocenter over a 20 - 40 s period. After Fourier Transform, frequency spectra for amplitude and phase of tumor and chest wall motions were performed for each patient. RESULTS: Cumulative distribution of CTV motion in absolute values showed that 95% of data ranged from 0 to 1 cm. Cumulative distribution of GTV motion in absolute values showed that 95% of data ranged from 0 to 0.8 cm. The correlation study demonstrated no specific relationship between respiratory and esophageal motions. CONCLUSION: The ITV margin for 3D conformal radiotherapy in esophageal cancer was 1 cm when 95% of motions were taken into account in this clinical study involving eight patients. Before using a free-breathing gating system, the correlation between external markers and target displacement during irradiation must be established for each patient.

Dosimetric consequences of breath-hold respiration in conformal radiotherapy of esophageal cancer.

The objective of this paper is to study the dosimetric impact of respiratory gated radiotherapy in locally advanced esophageal carcinomaand to define the optimal respiratory phase for this treatment. The study included 8 consecutive patients with squamous-cell carcinoma (SCC) or histologically proved adenocarcinoma, for both at least T3-T4 NX or TX N1 M0 stage. Informed consent was obtained before beginning the study. Three spiral scans were performed in breath-hold respiration: one acquisition in end expiration (EBH), one in end inspiration (IBH) and one in deep inspiration breathhold (DIBH); and one acquisition was performed in Free Breathing (FB). A 3 mm-margin was defined as Internal Target Volume (ITV) on FB CT-scan. No ITV was applied on EBH, IBH and DIBH CT-scan. Target volumes were analyzed and we performed dosimetric comparisons on DVH data of each CT-scan for PTV and Organs at Risk (OAR) (Conformity Index, V(dose), D(mean), Equivalent Uniform Dose). DIBH and IBH correlated with a 32% (p=0.77) and 20% (p=0.52) decrease in lung V(20) respectively as compared to FB (13.5%and 15.6% respectively versus 19.9%). DIBH and IBH correlated with a 25% (p=0.25) and 17% (p=0.39) decrease in cardiac V(40) respectively, as compared with FB (16.9% and 18.9% respectively versus 22.7%). For spinal cord irradiation, the minimum dose was obtained in IBH (36.5 Gy). Conformal radiotherapy with respiratory gating for esophageal cancer decreases the irradiated dose to OAR. We suggest that DIBH technique should be used when irradiation is performed using the spirometric system. In the Tidal Volume, the inspiration phase is the most favourable and should be chosen for irradiation with a free breathing gating system.

Prevalence of HIV infection among patients with leprosy in African countries and Yemen.

Screening for human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2) antibodies was carried out in the serum of 1,245 leprous patients and 5,731 controls selected in nine different centers from the Congo, Ivory Coast, Senegal, and Yemen Arab Republic. In Yemen, all sera were negative. In the Congo, the seropositivity among patients and controls was, respectively, 3.8 and 5.2%; in Senegal, it was 1.3 and 0.6%; and in the Ivory Coast 4.8 and 3.9%. Differences were not statistically significant, even considering lepromatous or tuberculoid forms (3.6% and 3.7%, respectively). HIV-2 antibodies were only detected in subjects from the Ivory Coast and Senegal. Using appropriate criteria for seropositivity (confirmation by Western blot, reactivity to HIV envelope glycoproteins) and a large selection of patients (several countries with several centers), it appears that leprosy (and specially the lepromatous form) is not a factor for HIV infection.

Evaluation of trimethoprim and sulphamethoxazole as monotherapy or in combination in the management of toxoplasmosis in murine models.

The combination of trimethoprim (TMP) and sulphamethoxazole (SMX) is commonly used for the prevention of cerebral toxoplasmosis although there is no firm experimental basis to support this regimen. We used strain RH tachyzoites for challenge in the acute murine model of toxoplasmosis and found that TMP administered as a single agent, failed to eradicate toxoplasma even at the highest dose (70 mg/kg per day). SMX alone at 600 mg/kg per day, protected ten out of ten mice, although inoculation of brain from surviving animals to naive mice resulted in the development of an encephalitis. When combined, TMP (60 mg/kg per day) and SMX (300 mg/kg per day) protected ten out of ten mice and gave a 'cure' in four out of four mice. In the chronic cystogenic murine models, the combination TMP plus SMX administered from day 5 for 15 days or from day 28 for 288 days, gave protection and even apparent toxoplasmal eradication ('cure') at the highest dosing (60/300 mg/kg per day). However, microscopic severe encephalitis was found in mice classified as 'cured' after reinoculation. This result makes the interpretation of 'cure' very difficult. In conclusion TMP and SMX act synergistically, SMX being the more active arm of the combination. The combination was efficient in preventing the lethal development of chronic toxoplasma encephalitis, but did not guarantee complete recovery.

Pseudotumoral lymphocytic hypophysitis successfully treated by corticosteroid alone: first case report.

We report the first case of pseudotumoral lymphocytic hypophysitis successfully treated by corticosteroids without surgery. A 27-year-old woman had been monitored for chronic headache 13 months after giving birth, associated with amenorrhea and galactorrhea. Cranial magnetic resonance imaging revealed a markedly enlarged pituitary gland with a suprasellar extension; the only biochemical abnormality was a mild hyperprolactinemia. Because of a putative diagnosis of prolactinoma, bromocriptine was prescribed at a dose of 5 mg daily, soon followed by the transitory appearance of menstruation. Two years later, panhypopituitarism was present and was revealed by acute adrenal insufficiency. Magnetic resonance imaging revealed that the pituitary mass was the same as previously described, but hormonal investigation showed evidence of complete hypopituitarism and no hyperprolactinemia. Nuclear antibodies were negative as well as other autoantibodies. Human leukocyte antigen serological Class II typing was DR3/DR4. Lymphocytic hypophysitis was then suspected; in the absence of visual complication and because this patient refused surgery, corticosteroids were attempted at a daily dose of 60 mg of prednisone for 3 months, progressively decreased for the next 6 months. Under this treatment, a gradual recovery of all pituitary hormones was observed and magnetic resonance imaging showed a reduction of two-thirds in pituitary mass. Five months after the end of corticoid treatment, our patient relapsed with panhypopituitarism and an increase of pituitary volume. She underwent steroid treatment, and a biopsy was performed and confirmed the diagnosis of autoimmune hypophysitis.(ABSTRACT TRUNCATED AT 250 WORDS)

[Optic ataxia localised in the left side of both 2 left homonymous visual hemifields]. / Ataxie optique localisée au coté gauche dans les deux hémichamps visuels homonymes gauches

Ocular ataxia localised to the left limbs on the left homonymous visual hemifields occurred after section of the right parieto-occipital junction zone performed to remove an intraventricular tumour. Since the right upper limb was unaffected, it must be presumed that, in man, there are two types of occipito-frontal connections, direct and crossed.

[Meningoradiculitis disclosing T-lymphocyte leukemia in HTLV-1 infection]. / Méningo-radiculite révélatrice d'une leucémie à lymphocytes T au cours d'une infection à HTLV1.

A case of HILV1-associated adult T cell leukaemia/lymphoma (ATLL) in à 21-year olf African woman is reported. The patient presented with lymphomatous meningoradiculopathy. The usual clinical features of ATLL were absent. Lumbar MRI showed a pial enhancement by DTPA-gadolinium of the conus medullaris which extended to the proximal cauda equina. Under systemic chemotherapy coupled with intrathecal chemotherapy the patient progressively improved, and at the second MRI examination complete disappearance of the lumbar enhancement was observed. MRI of the brain using axial and coronal T2-weighted sequences detected multifocal lesions of high-intensity signal in the subcortical white matter. ATLL is unusual in people of African origin. The ATLL-strongyloïdes infestation association has previously been reported, suggesting that parasitic infestation may be an important co-factor leading to the development of ATLL.