• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.46 no.3
• /
• pp.44-51
• /
• 2009

It is very important to verify generated setup errors in cancer therapy by using a high energy radiation and to perform the precise radiation therapy. Specially, the verification of treatment position is very crucial in special therapies like fractionated stereotatic radiotherapy (FSRT). The FSRT uses normally high-dose, small field size for treating small intracranial lesions. To estimate the developed FSRT system, the isocenter accuracy of gantry, couch and collimator were performed and a total of inaccuracy was less than ${\pm}1mm$. Precise beam targeting is crucial when using high-dose, small field size FSRT for treating small intracranial lesions. The EPID image of the 3mm lead ball mounted on the isocenter with a 25mm collimator cone was acquired and detected to the extent of one pixel (0.76mm) after comparing the difference between the center of a 25mm collimator cone and a 3 mm ball after processing the EPID image. In this paper, the radiation treatment efficiency can be improved by performing precise radiation therapy with a developed video based EPID and FSRT at near real time

• Progress in Medical Physics
• /
• v.9 no.2
• /
• pp.89-94
• /
• 1998

To make practical application of the MR image for stereotactic radiosurgery, the target point-achieved by acquisition of MR image in stereotactic radiosurgery planning system must agree with the actual isocenter of irradiation in real treatment. And the amount of distortion of the MR image must be known to make a correction for the agreement. A radish containing abundant water content was chosen as a homogeneous phantom for the purpose of verification of the agreement in this experiment. A dosimetric film was firmly attached to the small specially fabricated acryl plate and needle puncture was made through the film just into the acryl plate and a drop of oil was dropped into the hole of the film. The acryl plate with film was inserted into the radish and the dorp of oil represented the target point in MR image. After the image acquisition by stereotatic radiosurgery planning system, we achieved stereotactic coordinate of the target point represented by the oil drop. And we proceeded to actual irradiation to the target point according to the procedure of stereotactic radiosurgery. After the irradiation, the film in the radish was developed and processed and the degree of coincidence between the center of the radiation distribution and the target point represented by the hole in the film was measured. The discrepancy between two points was under 0.5 mm. so we could confirm good coincidence in homogeneous phantom such as radish. On the other hand, authors tried to use our home-made device for estimation of distortion of MR image.

• Journal of the Korean Institute of Navigation
• /
• v.17 no.1
• /
• pp.99-105
• /
• 1993

Underwater acoustic positioning systems have been extensively used not only in surface position fixing but also in underwater position fixing. Recently, these systems have been applied in the field of installation and underwater inspection offshore platforms etc. But in these systems are included the fixing errors as results of a signal with noise and irregular motion of vessel by ocean waves. In this paper to improve the accuracy of the position fixing a Kalman filter is applied to the short baseline(SBL) acoustic positioning system. The optimal position obtained by the Kalman filter is compared with the raw position and it is confirmed that the former is more accurate than the latter.

• Radiation Oncology Journal
• /
• v.28 no.3
• /
• pp.166-176
• /
• 2010

Purpose: To determine the appropriate prostate planning target volume (PTV) margins for 3-dimensitional (3D) conformal radiotherapy (CRT) and intensity-modulated radiation therapy (IMRT) patients treated with an endorectal balloon (ERB) under our institutional treatment condition. Materials and Methods: Patients were treated in the supine position. An ERB was inserted into the rectum with 70 cc air prior to planning a CT scan and then each treatment fraction. Electronic portal images (EPIs) and digital reconstructed radiographs (DRR) of planning CT images were used to evaluate inter-fractional patient's setup and ERB errors. To register both image sets, we developed an in-house program written in visual $C^{++}$. A new method to determine prostate PTV margins with an ERB was developed by using the common method. Results: The mean value of patient setup errors was within 1 mm in all directions. The ERB inter-fractional errors in the superior-inferior (SI) and anterior-posterior (AP) directions were larger than in the left-right (LR) direction. The calculated 1D symmetric PTV margins were 3.0 mm, 8.2 mm, and 8.5 mm for 3D CRT and 4.1 mm, 7.9 mm, and 10.3 mm for IMRT in LR, SI, and AP, respectively according to the new method including ERB random errors. Conclusion: The ERB random error contributes to the deformation of the prostate, which affects the original treatment planning. Thus, a new PTV margin method includes dose blurring effects of ERB. The correction of ERB systematic error is a prerequisite since the new method only accounts for ERB random error.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.42 no.2
• /
• pp.1-6
• /
• 2005

Ryu et al. proposed a multiple target DOA tracking algorithm using a linear sensor array. In Ryu's algorithm first, the signal subspace is estimated using sensor output and the angular innovations of targets are extracted from the estimated signal subspace. Next, the DOA's of targets are tracked using the angular innovations as the inputs of Kalman filters. Ryu's algorithm has good features that it has no data association problem and is efficient. However, Ryu's algorithm can't be a lied to an arbitrarily shaped array because it was proposed using linear sensor array. Actually, when the sensor array is used in the various application fields, sensors have a position error. Therefore, the sensor array can be an arbitrarily shaped array. In this paper, we propose a multiple target DOA tracking algorithm applicable to an arbitrarily shaped array, and it sustains the good features of Ryu's algorithm.

• Progress in Medical Physics
• /
• v.3 no.1
• /
• pp.53-62
• /
• 1992

Stereotactic implantation of intracranial lesions, and the development of stereotactic convergent irradiation, radiosurgery, techniques have to obtain the accurate coordinates of the tumor locations and that of critical organ. Computed tomography(CT) provides relatively precise imformations of tumor localization and surround the normal organs for conventional radiotherapy. This CT image use to extend for stereotactic radiosurgery procedures. Since the convergent irradiation technique in linear accelerator requires the target center coincident with gantry isocenter or radosurgery frame, the target coordinates must be described in accurately. We used the BRW stereotactic system for describing the target position in CT images This algorithm provides the coordinate conversions for orthogonal or non-orthogonal CT scan image. In this experiments, the target positions have shown the small discripancy within :to.3mm uncertanty in several known target positions in the phantom through the provided programs and it compared to that of BRW stereotactic systems.

• Radiation Oncology Journal
• /
• v.17 no.1
• /
• pp.84-88
• /
• 1999

Purpose :To develop a method for verifying a treatment setup in stereotactic radiotherapy by ma- tching portal images to DRRs. Materials and Methods : Four pairs of orthogonal portal images of one patient immobilized by a thermoplastic mask frame for fractionated stereotactic radiotherapy were compared with DRRs. Portal images are obtained in AP (anteriorfposterior) and lateral directions with a target localizer box containing fiducial markers attached to a stereotactic frame. DRRs superimposed over a planned iso-center and fiducial markers are printed out on transparent films. And then, they were overlaid over onhogonal penal images by matching anatomical structures. From three different kind of objects (isgcenter, fiducial markers, anatomical structure) on DRRs and portal images, the displacement error between anatomical structure and isocenters (overall setup error), the displacement error between anatomical structure and fiducial markers (irnrnobiliBation error), and the displacement error between fiducial markers and isocenters (localization error) were measured. Results : Localization error were 1.5$\pm$0.3 mm (AP), 0.9$\pm$0.3 mm (lateral), and immobilization errors were 1.9$\pm$0.5 mm (AP), 1.9$\pm$0.4 mm (lateral). In addition, overall setup errors were 1.0$\pm$0.9 mm (AP), 1.3$\pm$0.4 mm (lateral). From these orthogonal displacement errors, maximum 3D displacement errors($\sqrt{(\DeltaAP)^{2}+(\DeltaLat)^{2}$)) were found to be 1.7$\pm$0.4 mm for localization, 2.0$\pm$0.6 mm for immobilization, and 2.3$\pm$0.7 mm for overall treatment setup. Conclusion : By comparing orthogonal portal images with DRRs, we find out that it is possible to verify treatment setup directly in stereotactic radiotherapy.

• Progress in Medical Physics
• /
• v.10 no.2
• /
• pp.63-71
• /
• 1999

For the purpose of utilization in 3-D conformal radiotherapy and whole body radiosurgery, the Whole Body 3-Dimensional Topographic Radiation Therapy System has been developed. Whole body frame was constructed in order to be installed on the couch. Radiopaque catheters were engraved on it for the dedicated coordinate system and a MeV-Green immobilizer was used for the patient setup by the help of side panels and plastic rods. By designing and constructing the whole body frame in this way, geometrical limitation to the gantry rotation in 3-D conformal radiotherapy could be minimized and problem which radiation transmission may be altered in particular incident angles was solved. By analyzing CT images containing information of patient setup with respect to the whole body frame, localization and coordination of the target is performed so that patient setup error may be eliminated between simulation and treatment. For the verification of setup, the change of patient positioning is detected and adjusted in order to minimize the setup error by means of comparison of the body outlines using 3 CCTV cameras. To enhance efficiency of treatment procedure, this work can be done in real time by watching the change of patient setup through the monitor. The method of image subtraction in IDL (Interactive Data Language) was used to visualize the change of patient setup. Rotating X-ray system was constructed for detecting target movement due to internal organ motion. Landmark screws were implanted either on the bones around target or inside target, and variation of target location with respect to markers may be visualized in order to minimize internal setup error through the anterior and the lateral image information taken from rotating X-ray system. For CT simulation, simulation software was developed using IDL on GUI(Graphic User Interface) basis for PC and includes functions of graphic handling, editing and data acquisition of images of internal organs as well as target for the preparation of treatment planning.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.24 no.1
• /
• pp.197-205
• /
• 2024

Development of AI and big data-based algorithms to advance and optimize the recognition and detection performance of various static/dynamic vehicles in front and around the vehicle at a time when securing driving safety is the most important point in the development and commercialization of autonomous vehicles. etc. are being studied. However, there are many research cases for recognizing the same vehicle by using the unique advantages of radar and camera, but deep learning image processing technology is not used, or only a short distance is detected as the same target due to radar performance problems. Therefore, there is a need for a convergence-based vehicle recognition method that configures a dataset that can be collected from radar equipment and camera equipment, calculates the error of the dataset, and recognizes it as the same target. In this paper, we aim to develop a technology that can link location information according to the installation location because data errors occur because it is judged as the same object depending on the installation location of the radar and CCTV (video).

• 전자공학회논문지 IE
• /
• v.47 no.2
• /
• pp.38-46
• /
• 2010

In this paper, an autonomous surveillance-tracking system for Workers monitoring basing on the stereo vision scheme is proposed. That is, analysing the characteristics of the cross-axis camera system through some experiments, a optimized stereo vision system is constructed and using this system an intelligent worker surveillance-tracking system is implemented, in which a target worker moving through the environments can be detected and tracked, and its resultant stereo location coordinates and moving trajectory in the world space also can be extracted. From some experiments on moving target surveillance-tracking, it is analyzed that the target's center location after being tracked is kept to be very low error ratio of 1.82%, 1.11% on average in the horizontal and vertical directions, respectively. And, the error ratio between the calculation and measurement values of the 3D location coordinates of the target person is found to be very low value of 2.5% for the test scenario on average. Accordingly, in this paper, a possibility of practical implementation of the intelligent stereo surveillance system for real-time tracking of a target worker moving through the environments and robust detection of the target's 3D location coordinates and moving trajectory in the real world is finally suggested.