A generalized three-dimensional line-of-sight guidance with lead angle (GLOS) is presented for maneuvering targets. In the proposed guidance law, we define a desired line-of-sight (LOS) from the tracker by taking the target future maneuvers into account. Because of the limitation of the tracker field-of-view (FOV), the lead angles in the azimuth and elevation channels must be fractions of the azimuth and elevation angles for straight collision trajectory. Simulation results show that GLOS has better performance, i.e., lower miss distance and total control effort, than the conventional LOS guidance with lead angle.

Purpose: To quantitatively analyze central corneal thickness (CCT) in patients with primary angle closure glaucoma (PACG) and primary open‑angle glaucoma (POAG), and to evaluate its correlation with severity of glaucoma.Methods: In this retrospective study, records of patients with previously diagnosed POAG or PACG at a tertiary glaucoma service were reviewed. CCT was measured by ultrasound pachymetry. Mean deviation (MD) on visual field (VF) testing was recorded for glaucoma severity determination. CCT and age‑ and sex‑adjusted CCT were compared among the study groups using Student’s t‑test and analysis of covariance (ANCOVA), respectively. Univariate and multivariate regression models were used for correlation of age, MD and CCT.Results: A total of 115 patients with PACG, 215 with POAG, and 100 normal controls were included with mean age of 64.1±10.4, 59.9±10.5, and 62.04±10.80 years, respectively. CCT was thicker in PACG eyes (545.5±46.1 mm) as compared to POAG eyes (531.7±37.3 mm) and controls (531.0±38.3 mm) even after age and gender adjustment (ANCOVA, P=0.05). CCT was found to decrease with increasing age only in the POAG group (b=-0.57, P=0.01). Disease severity (MD of VF) was significantly and inversely correlated with CCT in both POAG and PACG eyes (b=1.89, P=0.02; and b=1.38, P=0.04, respectively) after age and sex correction.Conclusion: PACG eyes had thicker CCT as compared to POAG and normal healthy eyes in Iranian subjects. Severity of the disease was inversely correlated with CCT in eyes with both POAG and PACG.

Objective (s): The objective of this study was to document and explain bilateral differences in the Q angle.Materials and Methods: Two hundred limbs of healthy adult Indian volunteers were studied. The Q angle was measured using a goniometric method with the subjects supine, quadriceps relaxed and lower limbs in neutral rotation. The relative lateral placement of the tibial tuberosity with respect to the centre of the patella was measured. Appropriate statistical tests were used to determine the bilateral variability in the Q angle and the lateral placement of the tibial tuberosity. Inter-observer variation of the above mentioned parameters were studied in twenty limbs.Results: The average Q angle value of all the 200 limbs was 12.73oC; the mean value on the right was 12.86oC and 12.60oC on the left. When the Q angle and the lateral placement of the tibial tuberosity were considered in pairs a significant difference was noted in males. The Q angle value on the right side was more often greater than the left. The relative lateral placement of the tibial tuberosity showed a significant positive correlation with the Q angle. The intra-class correlation coefficient was 0.66 for the Q angle and 0.8 for the lateral placement of the tibial tuberosity.Conclusion: The present study shows that bilateral variability in the Q angle could be attributed to an alteration of the relative placement of the tibial tuberosity with respect to the centre of the patella.

Objective and Importance: The authors reported a case of plasmocytoma involving the cerebellopontine angle (CPA), which is a rare presenting location of intracranial extramedullary plasmocytoma. Clinical presentation: The patient was A 55-years-old woman who complained of vertigo and tinnitus for one year before. Admission, Neurological examination showed impairment of cerebellar tests. CT scan revealed a large mass lesion in the left CPA region. Intervention: The patient underwent a left retromastoid craniectomy and resection of the tumor. Histopathological studies of biopsy revealed plasmocytoma. Other studies including bone isotope scan and bone marrow aspiration did not show involvement of other parts of the body. Within 6 months of follow up there was No sign of progression of the tumor in CT scan. Conclusion: There are few reports of CPA solitary plasmocytoma. There is a potential risk for error in diagnosis in imaging and pathology. The current treatment is subtotal or radical resection combined whit radiotherapy.

Introduction: Dose distribution can be affected by diverse parameters, such as beam orientations, and collimator angles. These parameters should respect and maintain the international recommended levels during the realization of the quality assurance protocols of linear accelerators. This study aimed at evaluating the dosimetric effects on treatment quality considering the mechanical error fluctuations in the recommended range. Material and Methods: This study included ten patients with head and neck cancer. All of them were treated using three-dimensional conformal radiotherapy with the simple 3-field classic technique. Initially, an optimized treatment plan was computed for each patient. Afterward, similar calculations were executed by varying isocenter position, gantry and collimator angles. Eventually, dosimetric evaluations based on dose-volume histograms were studied and analyzed by Wilcoxon signed rank test for each plan. Results: The analysis of the dose-volume histograms of tumor volumes and organs at risk, as well as the dosimetry calculation, revealed that the small errors of 0. 5° in gantry and collimator angles have minimal effects on dose distribution. However, the variation in isocenter coordinating up to 1 mm may influence the patients’ treatment quality, particularly in the spinal cord and the brainstem, in which Wilcoxon's test showed significant effects in all plans. Conclusion: According to the results, the quality of the treatment plans is almost insensitive to the errors of the gantry and the collimator angles of the order 0. 5° though it is relatively sensitive to isocenter errors (1 mm). These should be reduced in order to avoid overdose when applying the conventional 3-field technique.