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O Morin

Publications and source records attributed to O Morin.

At least 19 recordsLinked to original sources
PubMed2006

The use of megavoltage cone-beam CT to complement CT for target definition in pelvic radiotherapy in the presence of hip replacement.

In Europe and the USA combined, over half a million people had a hip joint replaced in 2005, contributing to the increasing number of radiotherapy patients with metallic hip prostheses. The treatment plan for external beam radiation therapy is based on the delineation of the anatomy in the planning CT scan. When implanted objects of high atomic number (Z) material are present, however, severe image artefacts are generated in conventional CT, strongly hindering the ability to delineate some organs. This is particularly the case for the planning of prostate patients with hip prostheses. This short communication presents the use of a new imaging modality, megavoltage cone-beam CT, to complement the regular CT for target definition of prostate cancer treatment of patients with hip replacements.

Hip Prosthesis↗
PubMed2006

[Megavoltage cone-beam CT: Recent developments and clinical applications].

The Megavoltage cone-beam (MV CBCT) system consists of a new a-Si flat panel adapted for MV imaging and an integrated workflow application allowing the automatic acquisition of projection images, cone-beam CT image reconstruction, CT to CBCT image registration and couch position adjustment. This provides a 3D patient anatomy volume in the actual treatment position, relative to the treatment isocenter, moments before the dose delivery, that can be tightly aligned to the planning CT, allowing verification and correction of the patient position, detection of anatomical changes and dose calculation. In this paper, we present the main advantages and performance of this MV CBCT system and summarize the different clinical applications. Examples of the image-guided treatment process from the acquisition of the MV CBCT scan to the correction of the couch position and dose delivery will be presented for spinal and lung lesions and for head and neck, and prostate cancers.

Head and Neck Neoplasms↗
PubMed2006

Dose-guided radiation therapy with megavoltage cone-beam CT.

Recent advances in fractionated external beam radiation therapy have increased our ability to deliver radiation doses that conform more tightly to the tumour volume. The steeper dose gradients delivered in these treatments make it increasingly important to set precisely the positions of the patient and the internal organs. For this reason, considerable research now focuses on methods using three-dimensional images of the patient on the treatment table to adapt either the patient position or the treatment plan, to account for variable organ locations. In this article, we briefly review the different adaptive methods being explored and discuss a proposed dose-guided radiation therapy strategy that adapts the treatment for future fractions to compensate for dosimetric errors from past fractions. The main component of this strategy is a procedure to reconstruct the dose delivered to the patient based on treatment-time portal images and pre-treatment megavoltage cone-beam computed tomography (MV CBCT) images of the patient. We describe the work to date performed to develop our dose reconstruction procedure, including the implementation of a MV CBCT system for clinical use, experiments performed to calibrate MV CBCT for electron density and to use the calibrated MV CBCT for dose calculations, and the dosimetric calibration of the portal imager. We also present an example of a reconstructed patient dose using a preliminary reconstruction program and discuss the technical challenges that remain to full implementation of dose reconstruction and dose-guided therapy.

Calibration↗
PubMed2005

In vitro susceptibility testing of Candida and Aspergillus spp. to voriconazole and other antifungal agents using Etest: results of a French multicentre study.

Minimum inhibitory concentrations (MICs) of the antifungal agent voriconazole were determined using the Etest and compared with those of amphotericin B, itraconazole and fluconazole using 1986 clinical isolates of Candida spp. Voriconazole MICs were also compared with those of amphotericin B and itraconazole using 391 clinical isolates of Aspergillus spp. Voriconazole was found to have more potent activity and lower MIC values than amphotericin B, itraconazole and fluconazole against C. albicans, C. tropicalis, C. parapsilosis and C. kefyr. Against C. glabrata and C. krusei, voriconazole was more active than either of the other two azole antifungals but had similar activity to amphotericin B. For species of Aspergillus, MIC values of voriconazole were lower than those of amphotericin B and itraconazole against A. fumigatus and A. flavus, and were similar to those of amphotericin B against A. niger. Against A. terreus, MIC values for voriconazole and itraconazole were similar. A. terreus is known to be resistant to amphotericin B, and this was reflected in higher MIC values compared with those of voriconazole and itraconazole. Voriconazole therefore compares very favourably with other antifungal agents against a large number of clinical isolates of Candida and Aspergillus spp.

Amphotericin B↗
PubMed2004

[New antifungal agents and bronchopulmonary mycoses].

The frequency of respiratory mycosal infections has increased over recent Years. Diagnosis has been improved by recent epidemiological data and advances in radiological and mycological diagnostic methods. Two new antifungal agents have recently received marketing approval: voriconazole and caspofungine. Voriconazole belongs to the echinocandin family of antifungals. Sites of action of antifungals have become more diversified: amphotericins act on ergosterol directly, azolated agents act on the synthesis of ergosterol, flucytosine affects synthesis of nucleic acids, and echinocandins alter the fungal wall. Synergetic or additive combinations, such as amphotericin-caspofungine, or voriconazole-caspofungine, can be proposed for advanced disease. Thus both first intention and secondary treatments, particularly for systemic candidiasis and aspergillosis, have been modified. These new protocols take into consideration the severity of the mycosal infection, co-morbidity, and drug combinations as well as cost.

Antifungal Agents↗
PubMed2003

Fatal acute granulomatous pulmonary aspergillosis in a healthy subject after inhalation of vegetal dust.

A previously healthy 28-year-old man presented a few hours after inhalation of vegetal dust with acute bilateral community-acquired pneumonia, which caused death in 10 days despite treatment with broad-spectrum antibiotics, intravenous amphotericin B, inotropic support, and mechanical ventilation. A postmortem lung biopsy indicated miliary granulomatous pulmonary aspergillosis. Six similar previously published cases of acute granulomatous pulmonary aspergillosis are reviewed. This entity in adulthood may reveal a defect in neutrophil or macrophage function, such as late-onset chronic granulomatous disease.

Acute Disease↗
PubMed2002

[Mycologic surveillance of the environment for preventive invasive aspergillosis. Proposals for standardization of the methodologies and implementation].

A MAJOR RISK: The infection of immunodepressed patients by Aspergillus-type fungi increases morbidity and mortality, particularly in hematology units or during solid organ transplantation. Although present diagnostic means benefit from the progress over the last years, they remain limited and chemoprophylaxis protocols have still not demonstrated significant efficacy. THE NEED FOR RECOMMENDATIONS: Today, the handling of environmental risks is the only strategy that has proved its efficacy and usefulness. On the basis of administrative recommendations and data from the literature, a multicentric and pluri-disciplinary task force, grouping clinicians, microbiologists and hygienists, has assessed different methods and has proposed recommendations for the standardization and optimization of fungal surveillance of the environment.

Air Microbiology↗
PubMed2001

Longitudinal study of bacterial, viral, and fungal infections in adult recipients of bone marrow transplants.

The epidemiology of infections was studied in a retrospective cohort of 446 recipients of bone marrow transplants (BMTs; 92 of which were allogeneic and 354 of which were autologous) during 1993--1996. Infections that were microbiologically documented in 274 recipients included bacteremia, urinary tract infections, cytomegalovirus viremia, fungemia, invasive aspergillosis, and catheter-related infections. During the period of neutropenia, no differences were found between recipients of allogeneic BMTs and recipients of autologous BMTs with regard to the incidence and the nature of infection. After patients underwent engraftment, bacteremia, cytomegalovirus viremia, and invasive aspergillosis were significantly more common in recipients of allogeneic BMTs than in recipients of autologous BMTs. Deaths caused by infection were uncommon and were mainly the result of invasive aspergillosis. Therefore, empirical antimicrobial therapy should be the same for recipients of both allogeneic and autologous BMTs during the period of neutropenia; after engraftment, more attention should be paid to the risk of infection in allogeneic BMT recipients, particularly with regard to detection and prevention of invasive aspergillosis.

Adolescent↗
PubMed2001

[Emerging visceral mycoses].

The emergence of new fungal pathogens such filamentous fungi (Scedosporium, Fusarium) or yeast (Trichosporon) is a real problem for doctors who treat immunocompromised patients. These fungi present in our environment (Scedosporium, Fusarium) can also be on the skin (Trichosporon). They are responsible for invasive infections cause of morbidity and mortality because patients are immunocompromised and the fungi are resistant to antifungal treatment. Clinical manifestations are seldom specific, but cutaneous localisations are frequent. They are either the portal of entry of the infection or a metastatic localisation. The role of laboratory for identification of the fungus is essential.

Amphotericin B↗
PubMed2001

Delayed closed reduction of rotatory atlantoaxial dislocation in an adult.

We report a case of rotatory atlantoaxial dislocation due to a rugby injury in an adult. The patient presented with torticollis 4 weeks after the injury. The neurological evaluation was normal. Reduction proved difficult to obtain and required 10 days of skull traction followed by gentle manipulation. After reduction, dynamic cervical radiographs showed no instability and magnetic resonance imaging (MRI) confirmed that the transverse ligament was intact. After 6 weeks of immobilization in a Minerva jacket, a dynamic rotatory computed tomography (CT) scan confirmed that the atlantoaxial joint was stable. Such cases of atlantoaxial joint dislocation in adults treated by traction after a considerable delay are rare. In our patient, demonstration by MRI that the transverse ligament was intact led to the decision to use conservative therapy, which proved successful.

Adult↗
PubMed2001

Pseudallescheria boydii knee arthritis in a young immunocompetent adult two years after a compound patellar fracture.

Pseudallescheria boydii arthritis of the knee developed in a 32-year-old immunocompetent man 2 years after a compound patellar fracture contaminated with soil. No other potential portal of entry was identified, suggesting that the fungus remained latent for 2 years. Pseudallescheria arthritis often occurs after a prolonged latency period, causing minimal symptoms that contrast with the frequently severe radiological changes. Although this organism often shows limited sensitivity to most antifungal agents, our patient achieved a full recovery after surgical synovectomy and 6 months of itraconazole therapy (400 mg/ d). This case illustrates the importance of testing for fungi in patients with torpid arthritis, particularly when mild clinical symptoms contrast with severe bone and joint destruction.

Adult↗
PubMed2001

[Airborne molds in Nantes--effect of climatic factors].

Many cities are studying biological atmospheric and, particularly, pollen pollution, but they are having difficulties setting up a mold analysis network and only a few provide fungal spore counts. The significance of some of those spores, and Alternaria in particular, as major allergens is now well known. The number of Alternaria spores varies extensively according to weather conditions over the year.

Air Pollution↗
PubMed2001

[Bronchopulmonary aspergillosis: new developments].

Bronchopulmonary aspergillosis are in the news. Invasive pulmonary aspergillosis raise early diagnostic problems and prevention problems in immunocompromised patients. These infections are no unusual in chronic obstructive pulmonary disease. The diagnosis between aspergilloma and chronic necrotizing pulmonary aspergillosis can be difficult. In allergic bronchopulmonary aspergillosis, epidemiology and therapy are questionable. Real progress has been made due to thoracic computed tomographic scan and mycological methods. Better use of amphotericin B, of amphotericin B lipid formulations and of azole antifungal agents, combined with surgical resection if necessary should improve aspergillosis prognosis.

Amphotericin B↗
PubMed2001

[Primary cutaneous cryptococcosis in HIV-seronegative subjects].

BACKGROUND: Primary cutaneous cryptococcosis is an uncommon clinical entity characterized by direct skin inoculation without systemic involvement. We report four cases of this affection in HIV-negative patients seen between 1990 and 1999 in Nantes Dermatological Clinic. CASE REPORTS: Patients mean age was seventy. Three patients had recent exposure to soil or birds, and two remembered a trauma before the lesion appeared. In three cases the lesion was on the hand. In two cases the lesion was an ulcerated nodule, in another an abscess and in the last a cellulitis. Two subjects were treated by fludarabin and systemic corticosteroids for respectively chronic lymphocytic leukemia and Waldenstrom's macroglobulinemia. The third had a CD4 lymphopenia. Cultural examination confirmed the diagnosis. Treatment, with fluconazole in 3 cases and ketoconazole and itraconazole in 1 case, resulted in healing of the skin lesion in a few months. DISCUSSION: Recognition of primary cutaneous cryptococcosis as a clinical entity has long been debated. An altered immunological status is an important factor for developing this disease. There is often a clear history of trauma or exposure to soil or birds preceding the development of the lesion. Clinically it often looks like a papule or an ulcerated nodule. The lesion is confined to the skin without systemic involvement. The prognosis is excellent thanks to the use of oral antifungal imidazoles.

Aged↗
PubMed2000

[Cryptococcus neoformans infection in hematologic malignancies].

PURPOSE: Cryptococcus is an opportunistic infection that affects immunodepressed patients and is a classical complication of AIDS-stage HIV infection. The aim of this study was to investigate Cryptococcus neoformans infections in patients with hematological malignancies. METHODS: Six cases have been described of cryptococcosis detected in Nantes, France over the past 10 years in patients with hematological malignancies. RESULTS: This infection has been found particularly in the context of lymphoproliferative disorders (chronic lymphocytic leukemia, Waldenström macroglobulinemia, Hodgkin's disease, and non-Hodgkin's lymphoma), and also following cytotoxic therapy. In four cases, the patients were treated with fludarabine, which rapidly caused long-duration marked lymphocytopenia, notably in CD4 cells. Cell-mediated immunity plays a major role in systemic defense against C. neoformans. It therefore seems that fludarabine favors the spread of cryptococcal infections. CONCLUSION: In the context of lymphoproliferative syndromes treated with cytotoxic drugs, in particular fludarabine, it appears important to take into account the possible presence of cryptococcal infection in the presence of respiratory, neurological or cutaneous disorders, so that a correct diagnosis can be made and the appropriate treatment administered.

Adult↗
PubMed1998

[Unusual lung mycosis: Penicillium++ marneffei infection].

We report an uncommon radiographic finding which led to the diagnosis of Penicillium marneffei pulmonary mycosis in an HIV positive woman. The patient who lived in France had travelled several times to her native country. Thailand, prior to the development of fever, weight loss, skin lesions with a macular aspect around the umbilicus. The chest x-ray demonstrated non-excavated round opacities. Penicillium marneffei was isolated from alveolar lavage fluid and blood samples. This rare fungus is usually found in immunodepressed subjects, especially HIV+ patients (CD4 < 50) should be suspected in subjects who have travelled to endemic zones (Southeast Asia). Penicillium marneffei is considered as a criteria for AIDS. P. marneffei is the only dimorphic member of the Penicillium genus and has a particular affinity for the reticuloendothelial system. Clinical manifestations vary, usually with skin lesions. Mycology diagnosis is usually made on blood samples as well as alveolar lavage or pleural fluids. Antifungals (amphotericin B. itraconazole, ketoconazole) are generally effective but the risk of relapse underlines the importance of secondary prophylaxis in immunodepressed subjects.

Female↗
PubMed1998

[Rare pulmonary mycoses in patients with hematologic diseases].

Patients with hematology disease in post-chemotherapy medullary aplasia are susceptible to life-threatening bronchopulmonary mycoses, especially aspergillosis. Other less common pulmonary mycoses are also observed. We report 4 cases due to Penicillium purpurogenum, Acromonium strictum and Scedosporium apiospermum (n = 2) infections. These unusual fungi appear to be emerging as pathogens in this population. They have common ubiquitous, opportunistic and low pathogenicity characteristics in immunocompetent subjects. The major risk factor is neutropenia. Isolating one of these fungi in an immunodepressed patient modifies management protocols since certain unusual fungi such as Scedosporium are resistant to amphotericin B.

Acremonium↗