جستجوی مقالات مرتبط با کلیدواژه "image-guided" در نشریات گروه "پزشکی"

This study aims to evaluate the interchangeability between cone beam computed tomography (CBCT) and the optical surface scanning system (Catalyst) for daily positioning during radiation therapy in head and neck cancer patients. This study was designed as a prospective observational descriptive study divided into two parts. The first part involved a phantom study using the computerized imaging reference systems (CIRS) child atom phantom. It aimed to detect deviations in patient position across six degrees of freedom (lateral, longitudinal, vertical, rotation, roll, and pitch) using the optical light scanner and Catalyst and compare them with deviations detected by CBCT in the same treatment sessions. The second part included 252 sessions, during which 30 head and neck cancer patients were treated at Children Cancer Hospital 57357, Egypt, using both Catalyst and CBCT for setup treatment positioning. The differences between CBCT and Catalyst in all six degrees of deviation were not statistically significant (lateral (P = 0.175), longitudinal (P = 0.296), vertical (P = 0.110), rotation (P = 0.936), roll (P = 0.527), and pitch (P = 0.270)). The optical light scanner system Catalyst is comparable to CBCT. Surface scanning (Catalyst) has proven reliable and feasible for daily patient positioning, with the advantage of avoiding daily exposure to additional radiation.

Numerous efforts have been made over the past century. Various innovation techniques are increasingly gaining attention and gradually establishing the foundation of recent significant developments in the world of neurosurgery, among which varied stereotactic neuro-navigation designs and other novel emerging systems are being developed every day. This narrative review aims to describe basic concepts in frameless stereotaxy and summarize the primary principles of neuronavigation and clarify basic characteristics, such as the accuracy of this technique (frameless navigation), and emphasize the importance of designing phantom.

Methods and Materials/Patients

 The application of brain images to steer the surgeon to a target in the brain by utilizing the stereotactic principle of co-registration of the patient with an imaging study that permits brain surgery to be fulfilled with greater safety and smaller incisions by providing precise surgical guidance of the location of intracranial pathology is highly noticeable. General uses of frameless stereotaxy are explained and common benefits
are highlighted. It is genuinely inevitable to estimate the accuracy of these systems and discover sources of error.

The findings have provided considerable insight into recent findings on principles of frameless stereotactic surgery and novel developments for image-guidance systems.

The unprecedented development of image guidance has been much discussed. As a concluding note, several determinants, including updated imaging/registration, ease of use, robotic instruments, automated registration of increased accuracy, and the program’s potential for expansion to other disciplines, are all under development for image guidance.

Radiation therapy involves a multistep procedure; therefore, the error in patient set up is an inherent part of the treatment. Main purpose of this study was to determine the clinical target volume (CTV) to planning target volume (PTV) in head and neck cancer patients.
A total of 15 patients who had daily portal images during the treatment courses were randomly selected in the present study. Systematic (Σ) and random (σ) errors were evaluated in three directions. The Isogray treatment planning system and Elekta linear accelerator were used in this study. Moreover, we had used MOSIAQ software as arecord and Verify system. Setup margins were calculated using three published margin recipes, including the International Commission on Radiation Units and Measurements (ICRU) report 62, as well as Stroom’s and van Herk’s formulae.
Average magnitude of the translational errors was reported between 0.7 and 10 mm. The systematic and random errors for head and neck cancer patients were 3.55 (2.58-4.52) and 1.83 (1.56-2.10) mm, respectively. According to the ICRU report 62, as well as Stoorm’s and van Herk’s formulas, the required margins to cover the target were obtained within the ranges of 3.1-4.9, 6.4-10.5, and 7.7-12.7 mm, respectively.
According to the results of the present study, 6.5-10.5 mm extension in CTV to PTV margin can ensure that 90% of the head and neck cancer patients will receive a minimum cumulative CTV dose higher than or equal to 95% of the prescribed dose.

Medical image interpolation is recently introduced as a helpful tool to obtain further information via initial available images taken by tomography systems. To do this, deformable image registration algorithms are mainly utilized to perform image interpolation using tomography images.

In this work, 4DCT thoracic images of five real patients provided by DIR-lab group were utilized. Four implemented registration algorithms as 1) Original Horn-Schunck, 2) Inverse consistent Horn-Schunck, 3) Original Demons and 4) Fast Demons were implemented by means of DIRART software packages. Then, the calculated vector fields are processed to reconstruct 4DCT images at any desired time using optical flow based on interpolation method. As a comparative study, the accuracy of interpolated image obtained by each strategy is measured by calculating mean square error between the interpolated image and real middle image as ground truth dataset.

Final results represent the ability to accomplish image interpolation among given two-paired images. Among them, Inverse Consistent Horn-Schunck algorithm has the best performance to reconstruct interpolated image with the highest accuracy while Demons method had the worst performance.

Since image interpolation is affected by increasing the distance between two given available images, the performance accuracy of four different registration algorithms is investigated concerning this issue. As a result, Inverse Consistent Horn-Schunck does not essentially have the best performance especially in facing large displacements happened due to distance increment.