REAL-TIME PORTAL IMAGING IN RADIATION THERAPY

THE OBJECTIVE OF THIS RESEARCH IS TO DESIGN A PROTOTYPE HIGH-ENERGY IMAGING DEVICE TO REPLACE CURRENT METHODS OF FILM PORTAL IMAGING IN RADIATION THERAPY TREATMENT VERIFICATION. PRIOR WORK HAS SHOWN THAT PROJECTIONS OF AN IRRADIATED OBJECT VIEWED WITH A NARROW-STRIP, LIQUID-FILLED ION CHAMBER DETECTOR CAN BE MATHEMATICALLY RECONSTRUCTED INTO AN IMAGE WITH GREATER CONTRAST THAN CONVENTIONAL PORTALFILMS. IT IS NECESSARY TO INCREASE THE SPEED OF DATA ACQUISITION AND THE RECONSTRUCTION PROCESS SIGNIFICANTLY TO PRODUCE AN IMAGE WITHIN 10 SECONDS. THE AIM OF PHASE I RESEARCH IS TO DEMONSTRATE THE ABILITY TO COLLECT THE STRIP PROJECTIONS OF THE IMAGE AT THE RATE OFAPPROXIMATELY 10 MSEC PER PROJECTION FOR 200 PROJECTIONS. ASUITABLE IONIZING LIQUID, SAFE AND NONFLAMMABLE, MUST BE FOUND FOR CLINICAL USE. PHASE I RESEARCH WILL DEVELOP THE TECHNOLOGICAL APPROACH THAT WILL BE IMPLEMENTED IN PHASE II. A DEVICE THAT CAN PRODUCE IMAGES OF TREATMENT PORTALS WITHIN 10 SECONDS WILL ENABLE DAILY CHECKS OF ALL TREATMENT PORTALS AND MAKE POSSIBLE DAILY ADJUSTMENTS OF PORTALS IF NECESSARY. PATIENT MOVEMENT DURING TREATMENT WILL BE EVIDENT, AND THUS THE QUALITY OF TREATMENT WILL BE ENHANCED.