Caldwell C B
Department of Medical Imaging, University of Toronto, Sunnybrook Health Science Center, Ontario, Canada.
J Nucl Med Technol. 1997 Sep;25(3):201-4.
Radiation safety regulations require regular wipe testing to detect possible radioactive contamination. The objective of this work was to develop and test an accurate, convenient and inexpensive means of performing wipe tests with a conventional gamma camera.
An array of fifteen 3.2 x 3.2-cm square holes was chiseled through a previously-damaged collimator, substantially increasing the gamma camera's sensitivity for wipe testing. The sensitivity and the minimum detectable activity (MDA) were evaluated using low-activity sources of 99mTc, 111In, 67Ga, 201TI and 131I.
The wipe testing system had a sensitivity of 2.5 cpm/Bq for 131I, 2.9 cpm/Bq for 67Ga, 3.8 cpm/Bq for 99mTc, 4.1 cpm/Bq for 201TI and 4.3 cpm/Bq for 111In. In all cases, the MDA was less than 35 Bq for a 2-min counting time and an open-energy window.
The gamma camera wipe test system provides an accurate, inexpensive and easy method of meeting regulatory requirements for contamination monitoring of radioisotopes commonly used in nuclear medicine.
辐射安全法规要求定期进行擦拭检测以发现可能的放射性污染。本研究的目的是开发并测试一种使用传统伽马相机进行擦拭检测的准确、便捷且经济的方法。
在一个先前受损的准直器上凿出一排15个3.2×3.2厘米见方的孔，大幅提高伽马相机进行擦拭检测的灵敏度。使用99mTc、111In、67Ga、201TI和131I的低活度源评估灵敏度和最小可探测活度（MDA）。
该擦拭检测系统对131I的灵敏度为2.5计数每分钟每贝可，对67Ga为2.9计数每分钟每贝可，对99mTc为3.8计数每分钟每贝可，对201TI为4.1计数每分钟每贝可，对111In为4.3计数每分钟每贝可。在所有情况下，对于2分钟的计数时间和开放能量窗口，最小可探测活度均小于35贝可。
伽马相机擦拭检测系统提供了一种准确、经济且简便的方法，可满足核医学中常用放射性同位素污染监测的法规要求。
