The purpose of this note is to provide yet another example of the link between certain conformal geometries and ordinary differential equations, along the lines of the examples discussed by Nurowski [3]. In this particular case, I consider the equivalence problem for 3-plane fields D ⊂ TM on a 6-manifold M satisfying the nondegeneracy condition that D + [D, D] = TM . I give a solution of the eq...

Introduction: The use of electronic portal imaging devices (EPIDs) is a method for the dosimetric verification of radiotherapy plans both pretreatment and in-vivo. The aim of this study was to test a 2D EPID-based dosimetry algorithm for dose verification of some plans inside a homogenous and anthropomorphic phantom and in-vivo, as well. Materials and Methods: </strong...

Radiotherapy wedges constitute an important group within the generic classification of so-called Beam Modification Devices (BMD). Wedges are subdivided into Static, Dynamic, and Omni Wedges sug-groups. The standard static wedge attenuates the beam progressively, in such a way that the dose delivery is higher at the thin side, and lower at the broader side. The slope of the inferior surface has ...

Keywords Disease name Definition Diagnostic criteria and differential diagnosis Etiology Genetics Clinical description Prognosis Diagnostic methods Epidemiology Management Unresolved questions References Abstract Ependymoma accounts for 10% of all pediatric central nervous system tumors and originates in ventricular spaces or from residual intra-parenchymal ependymal cells. The most common loca...

Background: We report the case of a patient with an advanced carcinoma of the cervix treated using the new concept of LATTICE Radiotherapy (LRT). We describe the dose distribution, planning and delivery of treatment as well as the clinical evaluation of the patient during and at the completion of treatment. The basic principle of LATTICE is to create, within the tumor volume, multiple localized...

Hepatocellular carcinoma (HCC) continues to be one of the worst cancer conditions worldwide, being the sixth most common cancer and associated with a 5-year overall survival rate of only 5% (1). Surgery, either in terms of local resection or liver transplant, is still the treatment of choice, with 5-year survival rates of 30–70% (2). However, o 20% of patients qualify for this treatment because...

OBJECTIVE Assess the results of salvage conformal radiotherapy in patients with biochemical failure after radical prostatectomy and identify prognostic factors for biochemical recurrence and toxicity of the treatment. MATERIALS AND METHODS From June 1998 to November 2001, 35 patients were submitted to conformal radiotherapy for PSA > or = 0.2 ng/mL in progression after radical prostatectomy a...

The problem of the quantum modes of the scalar free field on anti-de Sitter backgrounds with an arbitrary number of space dimensions is considered. It is shown that this problem can be solved by using the same quantum numbers as those of the nonrelativistic oscillator and two parameters which give the energy quanta and respectively the ground state energy. This last one is known to be just the ...

Since the introduction of 3-dimensional conformal radiotherapy (3DCRT), new radiotherapy techniques have expanded the indication of radiotherapy for the treatment of hepatocellular carcinoma (HCC), from the hitherto palliative to a now curative-intent purpose. Intensity-modulated radiotherapy (IMRT), currently the most advanced radiotherapy technique, is considered an attractive option for the ...