SUMMARY Acoustic pulses were detected fiom a patient treated by a pulsed proton radiation beam. The dose rate of the proton beam was 0.3 cGy/pulse. The signals from 100 to 700 pulses were accumulated to improve the signal to noise ratio. After accumulation, the random noise level was negligibly small compared to the signal. These results suggest the feasibility of non-invasive monitoring of proton dose distributions in patients by sensing acoustic pulses generated during irradiation by a pulsed proton radiation beam. Radiat Oncol Invest 1995;3:42-45. 0 1995 Wdey-Liss, lnc.
Time-resolved acoustic pulses generated in water and in soft tissue by pulsed proton beam irradiation were observed. The spatial resolution of depth dose distribution in the clinically applied beam intensity is estimated about 3 mm by means of TOF measurement. The dependence of the acoustic signal intensity on the temperature of medium was examined. Proportionality of acoustic pulse intensity to absorbed dose per pulse was confirmed as well. These results suggest the possibility of clinical application to monitor dose distribution in the patient's body during irradiation of pulsed proton beam.
A two-dimensional clinical intravenous coronary angiography system, comprising a large-size view area produced by asymmetrical re¯ection from a silicon crystal using intense synchrotron radiation from a multipole wiggler and a two-dimensional detector with an image intensi®er, has been completed. An advantage of the imaging system is that two-dimensional dynamic imaging of the cardiovascular system can be achieved due to its two-dimensional radiation ®eld. This world-®rst two-dimensional system has been successfully adapted to clinical applications. Details of the imaging system are described in this paper.
A method of examination for coronary artery disease that is less invasive and easier than coronary angiography (CAG) has been sought. We have developed a dynamic intravenous coronary angiography (IVCAG) system using synchrotron radiation (SR) and have used it clinically. Four patients suspected of having angina pectoris underwent IVCAG. An SR beam was reflected asymmetrically with a silicon crystal to produce a wide (150 mm x 80 mm) and monochromatic (37 keV) X-ray beam, with an energy level to achieve high sensitivity to the contrast agent. Following an intravenous injection of contrast agent, irradiation was applied for 4 ms periods at 33 ms intervals for dynamic IVCAG at 30 images s-1. Images were acquired with an image intensifier and recorded with a digital fluorography system. The dynamic images permitted clear visualization of the coronary arteries and permitted evaluation of coronary anatomy. Two patients exhibited no stenotic lesions, one patient had a 90% stenosis in the right coronary artery, and the remaining patient had a 25% stenosis at the site of previous percutaneous transluminal coronary angioplasty in the left anterior descending artery (LAD). The total irradiation doses used for IVCAG were less than those for conventional angiography. Dynamic IVCAG can be readily used for the evaluation of coronary arteries.
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