Multidetector CT fluoroscopy and cone-beam CT-guided percutaneous transthoracic biopsy: comparison based on patient doses.

In this study, two different techniques used for image-guided percutaneous transthoracic needle biopsy have been compared in terms of patient dose: computed tomography (CT) fluoroscopy (performed on a Toshiba Aquilion 64), supplied with several multidetector CT (MDCT), and cone-beam CT (CBCT) (performed on a Philips Allura Xper FD20), supplied with a few C-arm flat-panel angiographic devices. Dose data (10 patients for each technique) have been collected, and organ doses and effective dose have been evaluated using software packages enabling to simulate real acquisition geometry and X-ray exposure. As a result, higher doses were found for MDCT compared with CBCT: the effective dose is 50% higher for MDCT; ratios between mean organ doses range between 1.2 and 1.7, except for breast (0.9) and oesophagus (3.7). Even though the observed differences are not always statistically significant, the general distribution of organ doses confirms that the MDCT-guiding technique delivers higher dose than the CBCT-guided one.

Volumetric analysis of the aneurysmal sac with computed tomography in the follow-up of abdominal aortic aneurysms after endovascular treatment.

PURPOSE: Our aim was to assess the usefulness of volumetric analysis for the follow-up of abdominal aortic aneurysms after endovascular repair (EVAR) and operator independence of the method. MATERIALS AND METHODS: We retrospectively evaluated 99 computed tomography (CT) exams of 33 patients. Two blinded operators assessed the volume before treatment and after EVAR at 1-3 and 12-24 months. Friedman's statistical test was used to assess the reproducibility of the method. The time required for postprocessing by the two operators was compared. RESULTS: One patient was excluded. Twenty-one patients showed no endoleak: 12/21 showed a volume reduction at both follow-up scans (9.7% and 19.5%, respectively); 8/21 showed an early volume increase (9.8%) with a late reduction (10.5%); 1/21 patient showed a volume increase at both follow-up scans (endotension). Eleven patients had an endoleak (one type I, nine type II and one type III); 4/9 type II endoleaks showed a volume reduction at both post-EVAR scans (8.5% and 19.5%). All other cases showed a volume increase after EVAR (type II 15.4%/16.8%, type I 24.1%/9.1%, type III 8%/10.7%). The Friedman statistical test assessed operator independence with p < 0.001. Mean difference between the two operators was 0.9% (0-4.3%). CONCLUSIONS: CT volume analysis is an accurate and reproducible modality for the follow-up of abdominal aortic aneurysms after EVAR. At early follow-up, contrast-enhanced CT remains mandatory to identify small endoleaks. For later follow-up, volumetric analysis would eliminate the need for contrast material in asymptomatic patients with stable or decreasing aneurysm volume.

Comparative study of jaws with multislice computed tomography and cone-beam computed tomography.

PURPOSE: The aim of this study was to compare the dosimetric and diagnostic performance of multislice computed tomography (MSCT) and cone-beam computed tomography (CBCT) in the study of the dental arches. MATERIALS AND METHODS: Effective dose and dose to the main organs of the head and neck were evaluated by means of thermoluminescent dosimeters (TLDs) placed in an Alderson Rando anthropomorphic phantom and using a standard CBCT protocol and an optimised MSCT protocol. Five patients with occlusal plane ranging from 54 cm to 59 cm who needed close follow-up (range 1-3 months) underwent both examinations. Image quality obtained with CBCT and MSCT was evaluated. RESULTS: Effective dose and dose to the main organs of the head and neck were higher for MSCT than for CBCT. Image quality of CBCT was judged to be equivalent to that of MSCT for visualising teeth and bone but inferior for visualising soft tissues. Beam-hardening artefacts due to dental-care material and implants were weaker at CBCT than at MSCT. CONCLUSIONS: When panoramic radiography is not sufficient in the study of the teeth and jaw bones, CBCT can provide identical information to MSCT, with a considerable dose reduction. MSCT is, however, indicated when evaluation of soft tissue is required.

Determinação da resistência de Staphylococcus aureus: um desafio? / Identification of drug resistance in Staphylococcus aureus: a challenge?

O objetivo deste estudo foi avaliar o perfil de resistência de cepas de Staphylococcus aureus, com diferentes padrões de eletroforese em campo pulsado (PFGE), em relação à resistência induzida à clindamicina e caracterizar cepas resistentes à oxacilina por testes fenotípicos. Do total de 18 cepas diferenciadas por PFGE, isoladas dos sítios nasais ou linguais de portadores adultos saudáveis, sem doença de base, sem histórico de uso de antibióticos e internações hospitalares, quatro (22,2%) apresentaram sensibilidade à clindamicina no antibiograma convencional, mas demonstraram resistência no D-teste; uma cepa (5,6%) foi caracterizada como BORSA (borderline) em relação à resistência a oxacilina e outra (5,6%) CA MRSA (S.aureus meticilina/oxacilina resistente associado à comunidade), ambas sensíveis à cefoxitina pelo teste de disco difusão. A caracterização molecular pela reação em cadeia para polimerase (PCR) da cepa identificada fenotipicamente como CA MRSA não revelou a presença do gene mecA, indicando tratar-se de cepa BORSA. Estes resultados apontam a importância do emprego rotineiro do D-teste como ferramenta para a determinação da resistência do tipo induzida à clindamicina, bem como para a importância da inclusão do teste de resistência à cefoxitina entre os métodos fenotípicos para caracterização de MRSA.

The aim of this study was to identify the resistance profile of Staphylococcus aureus strains, in relation to induced clindamycin resistance, and to detect oxacillin resistance by the routine phenotypic methods. The strains were isolated from nasal or lingual swabs taken from healthy adult carriers with no medical history of hospitalization or antibiotic treatment. Eighteen strains were distinguished by the different patterns generated by pulsed gel electrophoresis (PFGE). Four (22.2%) of these showed sensitivity to clindamycin by the conventional antibacterial susceptibility test, but demonstrated inducible resistance to it by the D-test. One strain (5.6%) was characterized as borderline oxacillin-resistant S. aureus (BORSA), and another (5.6%) as CA MRSA (community-associated methicillin-resistant Staphylococcus aureus). Both of these strains were shown to be cefoxitin susceptible by the disk diffusion test. The polymerase chain reaction (PCR) failed to detect the mecA gene in this last strain and it was thus classified as BORSA. These results show the importance of incorporating the D-test into the routine lab tests for S. aureus inducible clindamycin resistance and also of including the cefoxitin resistance test among the phenotypic methods for MRSA characterization.

Alanine and TLD coupled detectors for fast neutron dose measurements in neutron capture therapy (NCT).

A method was investigated to measure gamma and fast neutron doses in phantoms exposed to an epithermal neutron beam designed for neutron capture therapy (NCT). The gamma dose component was measured by TLD-300 [CaF2:Tm] and the fast neutron dose, mainly due to elastic scattering with hydrogen nuclei, was measured by alanine dosemeters [CH3CH(NH2)COOH]. The gamma and fast neutron doses deposited in alanine dosemeters are very near to those released in tissue, because of the alanine tissue equivalence. Couples of TLD-300 and alanine dosemeters were irradiated in phantoms positioned in the epithermal column of the Tapiro reactor (ENEA-Casaccia RC). The dosemeter response depends on the linear energy transfer (LET) of radiation, hence the precision and reliability of the fast neutron dose values obtained with the proposed method have been investigated. Results showed that the combination of alanine and TLD detectors is a promising method to separate gamma dose and fast neutron dose in NCT.

Characterisation of the TAPIRO BNCT epithermal facility.

A collimated epithermal beam for boron neutron capture therapy (BNCT) research has been designed and built at the TAPIRO fast research reactor. A complete experimental characterisation of the radiation field in the irradiation chamber has been performed, to verify agreement with IAEA requirements. Slow neutron fluxes have been measured by means of an activation technique and with thermoluminescent detectors (TLDs). The fast neutron dose has been determined with gel dosemeters, while the fast neutron spectrum has been acquired by means of a neutron spectrometer based on superheated drop detectors. The gamma-dose has been measured with gel dosemeters and TLDs. For an independent verification of the experimental results, fluxes, doses and neutron spectra have been calculated with Monte Carlo simulations using the codes MCNP4B and MCNPX_2.1.5 with the direct statistical approach (DSA). The results obtained confirm that the epithermal beams achievable at TAPIRO are of suitable quality for BNCT purposes.

Characterisation of the TAPIRO BNCT thermal facility.

Dosimetry and spectrometry measurements have been carried out in the thermal column of the research fast reactor RSV-TAPIRO (ENEA-Casaccia, Rome) in order to investigate its suitability for irradiation of cells or mice, with a view to research in the interests of boron neutron capture therapy (BNCT). The thermal column consists of a graphite moderator (40 cm thick) containing a lead shield (13 cm thick) in order to shield reactor background. The irradiation volume, inside this structure, has cubic shape (18 x 18 x 18 cm3). Besides measurements of fluence and dose rates in air or in phantom performed with thermoluminescence dosemeters (TLDs) and using the activation technique, dose and fluence profiles have been generated using a method based on gel dosemeters analysed with optical imaging. To check the consistency of the results, spectrometry measurements in the same irradiation volume have been performed by means of bubble detectors.

In-phantom imaging of all dose components in boron neutron capture therapy by means of gel dosimeters.

The experimental method for in-phantom imaging and profiling the absorbed dose in neutron capture therapy has been improved. The method separates the contributions of the various secondary radiation components and is based on suitably designed gel dosimeters in the form of layers. The discrimination of the dose components is achieved by means of pixel-to-pixel manipulations of images obtained with gel dosimeters having different isotopic composition. Large dose images are obtainable with this method, because the layer geometry of dosimeters avoids sensible variation of neutron transport due to the isotopic composition of gel. Operation modalities aimed at attaining more reliable results have been studied. Some results, together with the results of punctual measurements performed with conventional dosimeters and with MC calculations, are here reported.

In situ identification of mononuclear cells infiltrating cutaneous carcinoma: an immuno-histochemical study.

The present study was undertaken in order to investigate the exact nature of the cells surrounding cutaneous tumours. Formalin-fixed, paraffin-embedded sections were tested with a horse antihuman T lymphocyte serum and with IgG, IgA and IgM rabbit antihuman serum. All the sections were respectively treated with rabbit anti-horse or swine antirabbit peroxidase-labelled serum. The advantages offered by the immunoperoxidase technique are briefly discussed. T cells are in overwhelming proportion in comparison with IgG, IgA and IgM bearing cells. This seems a further demonstration that mononuclear infiltrate surrounding cutaneous carcinoma mainly represents a cell-mediated immune response.

[An uncommon pseudo tumoral skin disease; the so-called Papillomatosis cutis carcinoides. A review (author's transl)]. / Contributo alla conoscenza di una non commune forma di Pseudo-cancerosi cutanea: la papillomatosis cutis carcinoides

The review of the current literature on the subject is followed by the exposure of the clinical and histopathological data concerning a case of papillomatosis cutis carcinoides. The Authors conclude on the opportunity to maintain this nosographic pattern, to be enclosed among the cutaneous pseudo tumoral affections.