Development and validation of a new set-up simulator dedicated to ocular proton therapy at CNAO.

An Eye Tracking System (ETS) is used at CNAO for providing a stable and reproducible ocular proton therapy (OPT) set-up, featuring a fixation light (FL) and monitoring stereo-cameras embedded in a rigid case. The aim of this work is to propose an ETS set-up simulation algorithm, that automatically provides the FL positioning in space, according to patient-specific gaze direction and avoiding interferences with patient, beam and collimator. Two configurations are provided: one in the CT room for acquiring images required for treatment planning with the patient lying on a couch, and one related to the treatment room with the patient sitting in front of the beam. Algorithm validation was performed reproducing ETS simulation (CT) and treatment (room) set-up for 30 patients previously treated at CNAO. The positioning accuracy of the device was quantified through a set of 14 control points applied to the ETS case and localizable both in the CT volume and in room X-ray images. Differences between the position of ETS reference points estimated by the algorithm and those measured by imaging systems are reported. The corresponding gaze direction deviation is on average 0.2° polar and 0.3° azimuth for positioning in CT room and 0.1° polar and 0.4° azimuth in the treatment room. The simulation algorithm was embedded in a clinically usable software application, which we assessed as capable of ensuring ETS positioning with an average accuracy of 2 mm in CT room and 1.5 mm in treatment room, corresponding to gaze direction deviations consistently lower than 1°.

Time-resolved volumetric MRI in MRI-guided radiotherapy: an in silico comparative analysis.

MRI-treatment units enable 2D cine-MRI centred in the tumour for motion detection in radiotherapy, but they lack 3D information due to spatio-temporal limits. To derive time-resolved 3D information, different approaches have been proposed in the literature, but a rigorous comparison among these strategies has not yet been performed. The goal of this study is to quantitatively investigate five published strategies that derive time-resolved volumetric MRI in MRI-guided radiotherapy: Propagation, out-of-plane motion compensation, Fayad model, ROI-based model and Stemkens model. Comparisons were performed using an MRI digital phantom generated with six different patient-derived motion signals and tumour-shapes. An average 4D cycle was generated as well as 2D cine-MRI data with corresponding 3D in-room ground truth. Quantitative analysis was performed by comparing the estimated 3D volume to the ground truth available for each 2D cine-MRI sample. A grouped patient statistical analysis was performed to evaluate the performance of the selected methods, in case of tumour tracking or motion estimation of the whole anatomy. Analyses were also performed based on patient characteristics. Quantitative ranking of the investigated methods highlighted that Propagation and ROI-based model strategies achieved an overall median tumour centre of mass 3D distance from the ground truth of 1.1 mm and 1.3 mm, respectively, and a diaphragm distance below 1.6 mm. Higher errors and variabilities were instead obtained for other methods, which lack the ability to compensate for in-room variations and to account for regional changes. These results were especially evident when further analysing patient characteristics, where errors above 2 mm/5 mm in tumour/diaphragm were found for more irregular breathing patterns in case of out-of-plane motion compensation, Fayad and Stemkens models. These findings suggest the potential of the proposed in silico framework to develop and compare strategies to estimate time-resolved 3DMRI in MRI-guided radiotherapy.

Medications for COPD: a review of effectiveness.

Chronic obstructive pulmonary disease (COPD) is a common problem among patients presenting to primary care. This condition has multiple individual and combined treatment regimens. The goals of treatment are to improve quality of life, exercise tolerance, sleep quality, and survival; and to reduce dyspnea, nocturnal symptoms, exacerbations, use of rescue medications, and hospitalizations. All patients benefit from bronchodilator medications as needed. Long-acting inhaled anticholinergics are probably more beneficial than short-acting formulations. Use of inhaled corticosteroids might benefit patients with mild COPD who have an inflammatory component or significant reversibility on spirometry. Patients with moderate to severe disease benefit from the use of long-acting inhaled anticholinergics, inhaled corticosteroids, and possibly a long-acting beta2 agonist or mucolytics. For rescue therapy, short-acting beta2 agonists or combination anticholinergics with a short-acting beta2 agonist should be used. Inhaled corticosteroids should be considered before initiating a long-acting beta2 agonist. Caution should be used if a long-acting beta2 agonist is discontinued before initiation of an inhaled corticosteroid because this may precipitate exacerbations. Evidence to support the use of mucolytics, oral theophylline, and oral corticosteroids is limited. Patients with severe hypoxemia (i.e., arterial oxygen pressure less than 55 mm Hg or oxygen saturation less than 88 percent) should be given continuous oxygen.

Steroids ineffective for pain in children with pharyngitis.

In children with acute pharyngitis, oral dexamethasone does not provide clinically significant reductions in time to initial or complete pain relief. Reserve its use for children with group A beta-hemolytic streptococcus pharyngitis who have moderate to severe pain, realizing that the benefit is of questionable significance.

Suturing unnecessary for hand lacerations under 2 cm.

Hand lacerations less than 2 cm long without tendon, joint, fracture, or nerve complications and not involving the nail bed can be cleaned and dressed without suturing, with similar cosmetic results and time to resume normal activities. Moreover, managing these uncomplicated hand lacerations conservatively could result in better use of medical resources and improved patient satisfaction due to less pain and less time spent in the emergency department.