The m.CAM gamma camera (Siemens Medical Solutions USA) is designed for planar imaging of pharmaceuticals labeled with gamma-emitting radionuclides, in a range of laboratory animals, from mice to small primates or dogs.
The system consists of a single High Definition Digital Detector (HD3) mounted onto a portable stand. The HD3 head may be rotated over 90 degrees, for imaging at any angle between horizontal (face up) to vertical (face out). The maximum imaging field-of-view (FOV) is 53.3 cm (21”) x 38.7 cm (15.25”) with an intrinsic resolution of 3.2 mm.
The m.CAM is equipped with a Low Energy High Resolution (LEHR) collimator for imaging radionuclides such as Tc-99m (140 keV), and a Medium Energy Low Penetration (MELP) collimator for radionuclides such as In-111 (172, 247 keV). The system resolution is 4-20 mm (6.3 mm at 10 cm, LEHR with Tc-99m) depending upon gamma ray energy, subject size and collimator.
Achievable image pixel sizes range from 19.18 mm (32 x 32 image matrix, zoom factor = 1) down to 0.187 mm (1024 x 1024 image matrix, zoom factor = 3.2). Inherent system deadtime is 5.74 msec, resulting in a count rate data loss of 20% at 38,400 counts per second (cps). System sensitivity (Tc-99m, 15% energy window) is 172 cpm/mCi for the LEHR collimator, and 237 cpm/mCi for the MELP collimator. Up to six independent energy windows (50 keV – 600 keV) can be selected.
The m.CAM is an ideal instrument for biomedical research laboratories to quantitatively measure the biodistribution of radiolabeled diagnostic and therapeutic compounds in vivo. The system is capable of acquiring conventional 2D (planar) static images and dynamic images.
A Tomographic Accessory for 3D SPECT imaging of mice and rats is currently under evaluation. The large FOV has been used to scan up to 12 mice at a time, yielding high throughput planar imaging with consistent imaging characteristics and synchronized dynamic data across entire cohorts of animals.
SPECT: 100 µCi (3.7 MBq) Tc-99m-MDP, 0.6 mm pixels