Model L-840 Dual Source Scatter Phantom

The Model L-840 simulates in-vivo scatter conditions required to measure gamma camera deadtime.  

Deadtime is the interval in which a gamma camera while processing incident radiation is insensitive to additional radiation. Measurement of these phenomena is important because during higher count rates, losses of data during the ‘deadtime’ degrade the quantitative data. Accurate measurement allows for the mathematical correction of the deadtime losses.  

During standard clinical conditions, the deadtime is a function of the scatter within the radiation source and its immediate surroundings. The phantom provides the simulated characteristics of forward and back scatter of the ^99mTc gamma rays and allow the measurement* of the camera’s deadtime.

*The deadtime measurement can typically be acquired in less than 15 minutes. The phantom is made of acrylic and has two holes, spaced 5 cm apart (and 5 cm from the face of the phantom) to accommodate the radioactive sources (not included) to measure the count rates and associated deadtime.