CCD Camera Monitor Research Articles

Study of cellulose pyrolysis using an in situ visualization technique and thermogravimetric analyzer

A technique has been developed to study cellulose pyrolysis by in situ visualization of cellulose transformation in a quartz capillary under a microscope using a CCD camera monitoring system and Raman spectroscopy. The processes and temperature of cellulose transformation during pyrolysis reaction can be observed directly. In situ visualization of reaction revealed that how oil is generated and expulsed concurrently from cellulose during pyrolysis. The in situ visualization result is the first direct evidence to show cellulose pyrolysis transformation. Pyrolysis characteristics were investigated under a highly purified N2 atmosphere using a thermogravimetric analyzer from room temperature to 500°C at the heating rate of 5°C/min. The results showed that three stages appeared in this thermal degradation process. Kinetic parameters in terms of apparent activation energy and pre-exponential factor were determined.

Development and Evaluation of a Target-tracking Radiation-therapySystem Using a Multileaf Collimator (MLC) Synchronized with MovingOrgans

A target-tracking radiation-therapy (RT) system that tracks the movement of a treatment target resulting from internal organ movement has been developed, and the system was evaluated for effectiveness. The developed radiation-therapy system determines the limit of the MLC (multileaf collimator) movement range with an acquired maximum displacement value of target movement during the radiotherapy planning stage and moves the MLC to continuously detect and synchronize the displacement of the abdominal by using a CCD camera monitoring system during real-time RT treatment. The system consists of a Co-60 teletherapy unit, an abdominal displacement detection system to correlate the movement of internal organs, and a MLC moving stage synchronized with the abdominal displacement. The effectiveness of the RT system was evaluated by analyzing the beam penumbra from the dose distribution on films (Gafchromic EBT) installed within a moving phantom. Penumbra widths (80%/20%) were measured for the nominal left (perpendicular to leaf motion) and right (parallel to leaf motion) directions of the x-axis and the y-axis for a fixed phantom and fixed MLC (3.3 mm/3.5 mm and 3.7 mm/3.1 mm), a moving phantom and a fixed MLC (9.0 mm/8.2 mm and 9.1 mm/8.8 mm), and a moving phantom and a moving MLC (3.7 mm/3.5 mm and 3.7 mm/3.8 mm). Percent area deviations of the 100% to 80% field of the maximum dose for the exposure condition of a fixed phantom and a fixed MLC were a relatively low value of 0.64% and a relatively high value of 15.04%, as compared to the values for a moving phantom and a fixed MLC and for a moving phantom and a moving MLC. With the method to move the MLC by passive synchronization with organ motion, the target-tracking radiation-therapy system was successfully implemented and was evaluated for performance. In future studies, various verification processes should be performed prior to the application of the system in a clinical situation.

SU‐FF‐T‐299: The Use of Beam Fluency to Assure Image‐Guided Radiosurgery Accuracy

Purpose: The purpose of this study was to accelerate and improve the measurement process of Cyberknife individual beam accuracy using a novel detector (XRV‐100, Logos Systems, Scotts Valley, CA) consisting of a three‐dimensional scintillator screen geometry and real‐time CCD camera monitoring. Method and Materials: The XRV‐100 hardware consists of a 60 degree cone laminated with conventional Gadox X‐ray scintillator phosphor. As an x‐ray beam passes through the cone, two spots of visible light are formed by Compton scattering at the entry and exit points. These two spots of light define not only the path of the radiation through three‐dimensional (3D) space but also the energy profile of the beam fluence. While QA treatment plans are administered by the radiosurgery system, the CCD camera and monitoring software view the interior of the scintillator cone and record the position of each beam in real‐time. Fiducial spheres mounted in proximity to the scintillator allow the Cyberknife system imaging system to precisely target treatment plans within the cone volume. Several Cyberknife beam collimators were profiled with the XRV system and the fluency data was compared with historical dose data taken with traditional water tank systems. AQA and isocenter end‐to‐end treatment plans were also performed on the XRV detector. Results: Beam fluency field widths and penumbras captured with the XRV using the Cyberknife 10 mm collimator at a SAD of 75 cm compare within 2% of water tank dose data taken at a depth of 50 cm. The AQA vector results confirmed Cyberknife submillimeter accuracy. Conclusion: The XRV results demonstrate that 3D beam fluency metrology can be accurate, fast, and a powerful adjunct to existing radiosurgery QA systems. This detector system is independent of the laser‐beam CAX alignment and improves the measurement methodology by measuring the delivery accuracy of the x‐ray beams directly.

Thermoelasticity and CCD analysis of crack propagation in AA6082 friction stir welded joints

The advantages of friction stir welding (FSW) process compared to conventional fusion welding technologies have been clearly demonstrated in recent years. In the present study, AA6082 FSW joints were produced by employing different welding parameters. The principal aim of this work is to apply thermoelastic stress analysis (TSA) to study crack propagation characteristics of friction stir welded aluminum sheets, during cyclic fatigue tests. The crack propagation experiments were performed by employing single edge notched specimens; fatigue tests were performed under tension with load ratio R = 0.1. All the mechanical tests were conducted up to failure. The TSA measurement system allowed crack evolution to be observed in real-time during fatigue cycles and stress fields to be derived on the specimens from the measured temperature variation. The thermoelastic data were used to analyse principal stresses and principal strains on the specimens surface and the crack growth rate during tests. In addition, it was possible to evaluate all the joints defects effects, as a function of welding parameters, correlating effects on different crack growth rate and instabilities. The achieved results were compared with those obtained by classical CCD camera monitoring of crack front propagation during cyclic loading and all the results were validated by employing finite element analysis performed with ABAQUS software.

A Washing Toilet Seat with a CCD Camera Monitor to Stimulate Bowel Movement in Patients with Spinal Cord Injury

The objective was to study the effectiveness of a modified washing toilet seat equipped with a CCD camera monitor and an electronic bidet to facilitate precise hitting of the anal area with water streams to stimulate bowel movement in patients with spinal cord injury (SCI). There were 20 subjects, all of whom had traumatic SCI, were at least 5 mos post acute injury, and could change their position on the toilet seat while watching the monitor. Stimulation of bowel movement with the modified toilet seat was provided for a maximum of 30 mins. Success or failure to induce bowel movement was evaluated as related to injury level, ASIA impairment scale, and ability to voluntarily increase anorectal pressure, measured with a manometory. Bowel movement was successfully induced in 15 of the 20 patients (75%). Success was not related significantly to injury level, ASIA impairment scale, or ability to voluntarily squeeze. Compared with their usual manner of bowel management, for which they spent more than 30 mins, time needed for successful bowel movement was shortened in 11 of 13 patients. No complications were observed. This preliminary study suggests that our newly modified washing toilet seat with a monitoring system could be a useful alternative for bowel management in patients with SCI.

SU-FF-J-36: Clinical Implementation of An Eye Fixing and Monitoring System with Head Mount Display

Purpose: A system to non-invasively fix and monitor eye by a head mounted display (HMD) with a CCD camera for stereotactic radiotherapy (SRS) of uveal melanoma has been developed and implemented clinically. Method and Materials: The eye fixing and monitoring system consists of a HMD showing patient a screen for fixing eyeball, a CCD camera monitoring patient's eyeball, and an immobilization mask. At first, patient's head was immobilized with a mask. Then, patient was instructed to wear HMD, to which CCD camera was attached, on the mask and see the given reference point on its screen. While patient stared at the given point in order to fix eyeball, the camera monitored its motion. Four volunteers and one patient of uveal melanoma for SRS came into this study. For the volunteers, setup errors and the motion of eyeball were analyzed. For the patient, CT scans were performed, with patient's wearing HMD and fixing the eye to the given point. To treat patient under the same condition, daily CT scans were also performed before every treatment and the motion of lens was compared to the planning CT. Results: Setup errors for four volunteers were within 1 mm and the motion of eyeball was fixed within the clinically acceptable ranges. For the patient with uveal melanoma, the motion of lens was fixed within 2 mm from daily CT scans. Conclusion: An eye fixing and monitoring system allowed immobilizing patient as well as monitoring eyeball and was successfully implemented in the treatment of uveal melanoma for SRS.