PEDIATRIC HEAD CT EXPOSURE DOSES IN TUNISIA: A PILOT STUDY TOWARDS THE ESTABLISHMENT OF NATIONAL DIAGNOSTIC REFERENCE LEVELS.

The purpose of this study was to assess and analyze the radiation doses during head pediatric CT from different CT units within six Tunisian hospitals representing different geographic regions in order to optimize the dose given and minimize the radiology risk to this category of patients and towards the derivation of national diagnostic reference levels. Patient data and exposure parameters were collected for four age groups (<1, 1-5, 5-10 and 10-15 y). Clinical protocols and exposure settings were analyzed. Doses were collected in terms of CTDIvol and DLP values. Effective and Organ doses to specific radiosensitive organs were estimated using the Monte Carlo simulation software 'Impact CTDosimetry'. Results showed large variations in CT protocols and doses between different radiology departments. CTDIvol and DLP values demonstrated a broad range between the CT units and between the axial and helical scan techniques in the same unit. CTDI vol values were estimated to be 24.9, 31.7, 45.5 and 47.8 mGy for <1, 1-5, 5-10 and 10-15 y age groups, respectively. In term of DLP, median values were ~346, 528, 824, 897 mGy cm for the same age groups, respectively. Effective dose ranged from 1.4 to 5 mSv. Dose values were comparable with those reported in the literature. The study shows an evident need for continuous training of staff in radiation protection concepts, especially within the regional hospitals, emphasizes the importance of the production and the update of recommendations and good practice guidelines using interdisciplinary working groups and opens the way for the establishment of national DRLs.

Imaging of benign lipomatous tumours of the limbs in children.

BACKGROUND: Lipomatous tumours of the limbs in children are rare, and lipoblastoma is the most common soft tissue tumour. Most of them have typical imaging features, but their clinical presentation and their management may vary, depending on the exact histological subtype. The aim of our study is to illustrate the main clinical, radiological and histological features of the different benign lipomatous tumours in children. METHODS: Review of the literature. RESULTS: It is about a descriptive study of paediatric cases of benign lipomatous tumours of limb in children. CONCLUSION: The imaging findings are helpful and can provide essential components for the diagnosis.

[Quality control--patient doses--guidance dose levels from diagnostic radiology in Tunisia]. / Controle de qualite--dose patient--niveaux de reference en radiodiagnostic en Tunisie.

BACKGROUND: Radiation doses from diagnostic radiology are the most important exposure collective doses of the man. Entrance Surface Dose is one of the basic dosimetric quantities for measuring the patient dose and hence, an excellent tool for optimization purposes and for comparison with the international reference values. AIM: The aim of the study was to assess the delivred quantitis of rayon x to patients who undervent radiography; METHODS: For the first time in Tunisia the doses delivered to the patient undergoing the most common type of X ray examinations (chest, abdomen, lumbar spin) were performed in two university hospitals of Tunis. Entrance Surface Dose measurements were conducted using thermoluminescent dosimeters calibrated at the National Centre of Radiation Protection. Before measurements, quality control tests were carried out on each radiological equipment used for examinations. RESULTS: From this study of 112 patients, it was deduced that the obtained values were comparable to the internationally recommended guidance levels. The diagnostic guidance dose levels established for Tunis area are preliminary results. The study should therefore be implemented on a national scale as an approach to establish the national guidance levels.

[Radon in Tunisian buildings]. / Le radon dans les maisons Tunisiennes.

Radon is a natural radioactive gas produced by decay of uranium and radium present in soils. Diluted in air, in confined atmospheres, it may accumulate in high concentrations. Inhalation of radon and its progeny is thought to increase lung cancer risk. For the first time, air radon concentrations were determined in 1151 dwellings situated in all the inhabited regions of Tunisia, using open alpha-track dosimeters exposed during two months. The median of 1864 measurements was 36 Bq m(-3) (with a maximum of 512 Bq m(-3), most of them being less than 100 Bq m(-3). All results were under the International Instances recommended range.

[Treatment of hydatid cyst in sheep. Assay of a new scolicide]. / Traitement du kyste hydatique chez la brebis, essai d'un nouveau scolicide.

OBJECTIVE: The main of this study was to show the rapidity of the protoscolicide action of a synthetic compound, dipeptide methyl ester when it is injected under echographic control into hydatid cyst of sheep. MATERIALS AND METHODS: Fourthty sheep with hydatid cysts, repaired at echography and punctionable are treated by dipeptide methyl ester injection at the dose of 110 mM. RESULTS: In vitro tests have allowed to define the efficacy dose of dipeptide methyl ester which is 110 mM. At echography, after injection of the drug, from the first minutes, a detachment of the inner membrane, a diminution of the size of the treated cyst were observed. The cyst content is modified. The sheep autopsy was realized after 4.6.12 and 17 weeks after the injection and showed a size reduction, a treated cyst calcification. CONCLUSION: The dipeptide methyl ester injection into hydatid cyst induces rapidly a morphological alteration, they are calcified. The advantage of this compound is its very rapidity action, this could decrease dissemination risks of hydatid liquid in the organism during operation. Also, this drug permits to reduce the operation time.

[Primary T-cell lymphoma of the pancreas in children]. / Lymphome T primaire du pancreas chez l'enfant.

Involvement of the gastrointestinal tract is frequently reported among the extranodal sites of non-Hodgkin's lymphoma, but primary lymphoma of the pancreas is very rare. We report the case of a 11-year-old boy explored for epigastric pain with fever leading to the diagnosis of high-grade primary non Hodgkin's T-cell lymphoma, originating from pancreas. This pancreatic lesion is documented by sonography, CT and MRI. This patient died quickly with sever infection.

[The hydatid cyst of the lung in children: 54 cases]. / Le kyste hydatique du poumon chez l'enfant. A propos de 54 cas.

The purpose of this retrospective study is to clarify the clinical, radiological and evolutionary aspects of the hydatid cyst of the lung. Over a period of 9 years (January, 1983 - December, 2001), we brought together in the pediatric service B of Children's hospital of Tunis, 54 cases of hydatid cyst of the lung. The average age is of 7 years 3 months (extremes 2 and 14 years), and the sex- ratio of 1,16. 61% of the children are of rural origin. Bronchpulmonary infection is the most frequent circumstance of discovery (72 % of cases). hemoptysis is revealing in 37% of cases. Discovery is fortuitous in 7% of cases. The radiography of the chest is of a big diagnostic contribution. The radiological aspects obtained are: a homogeneous opaqueness (61%), a diverse opaqueness (26%), an image of lung abscess (22 %), an aspect of floating membrane (4 %), a pleural effusion (9%), and an opaqueness with growing gas (4%). Chest echography was contributory in 77% of cases. 74% of the children were operated without complications. The others were lost.

[Hypertrophic osteoarthropathy revealing a malignant thymoma in a child]. / Osteoarthropathie hypertrophiante revelant un thymome malin chez un enfant. Apport de l'imagerie.

Association of hypertrophic osteoarthropathy and malignant thymoma is very rare in children. Authors report a case of a 14 year old girl followed for rheumatic fever since she was 8 years old. She was explored for arthralgia. The exam showed hippocratic fingers, soft tissues hypertrophy of lower limbs and dyspnoea. Plain radiography had demonstrated symmetrical ossifying periostisis in tubular bones of lower limbs evocating hypertrophic osteoarthropathy diagnosis. Chest radiography has demonstrated bilobate anterior mediastinal mass. Ultrasonography and MRI revealed a voluminous anterior mediastinal mass with cystic and fleshy components. Thymic adenocarcinoma diagnosis was made by surgical biopsy.

[First seizure in children. Exploration strategy]. / Première crise convulsive de l'enfant. Stratégie d'exploration.

We have carried out a retrospective study on 51 children aged between 2 years 3 months and 13 years in order to determine the findings and to define the indications of neuroimaging modalities in children with a first unprovoked seizure. Children who had neuroimaging studies were divided into two groups based on the results of neuroimaging normal or abnormal. We have compared the two groups according to each clinical and electroencephalographic parameters studied. Neuroimaging abnormalities were found in 47% of cases. According to our results and literature review, we concluded that the imaging should be done if we have at least one of the criteria: an abnormal neurological examination after the seizure and focal slowing waves on the electroencephalogram.

Facial features and skeletal abnormalities in Larsen syndrome--a study of three generations of a Tunisian family.

We report on a 3 generation study of a Tunisian family, in which eight subjects had or have features of Larsen syndrome: three siblings, two females and one male are affected with flattened facies, multiple congenital joint dislocations, and club foot deformities. Five other family members were recognised as being variably affected with the syndrome. Over the three generations, despite the characteristic facial features being the most constant clinical signs of the syndrome, none of those still living had palatal clefts, the multiple infantile deaths in this family, however, were characterised by an association with cleft palate.