Page 19 - Clinical Manual of Small Animal Endosurgery

Rigid Endoscopy 7

Video signals are then sent to a monitor, which can vary in size and
resolution. Although a high-resolution monitor cannot improve a poor
image, it is important for it to match or surpass the video camera’s reso-
lution (500 lines for single-chip cameras and 750 lines for three-chip
ones). It is also important that the video input format quality equals the
video camera quality. In particular, Y/C (also called S) video format is
recommended for single-chip cameras, and RGB video input should be
used for a three-chip camera. These signal formats are capable of high
resolution (the latter more than the former), as they separate different
aspects of signal information (such as brightness, colour and synchroni-
sation) into more than one signal (two in S format and four in RGB
format), thus minimising artefacts. Flat widescreen LCD high-resolution
monitors are required for use with high-definition cameras, in order to
benefit from the perceived three-dimensional effect.
Cameras are not generally autoclavable. They can be sterilised by cold
soaking in most instances, but during surgery it is more common to use
a disposable camera sheath to provide asepsis (Fig. 1.7).
Finally, a series of different video accessories completes the video
system. Until some years ago the most widespread devices were video
printers and VHS recorders. With the advances in digital technology,
digital recording devices have become readily available and affordable.
Still images and/or video clips can be captured and stored for editing,
printing and reproduction. The main advantages of digital devices are
the lack of degradation in photo quality over time and in successive pas-
sages, and the saving of storage space.
More recent devices combine all video system components (CCU, light
source and image recording) into one unit, apart from the camera
head (Fig. 1.8). Their compactness makes them easy to use in clinic or
field settings but the set-up cost may be greater than using modular

Fig. 1.7 An unscrubbed surgical assistant helps the surgeon place a sterile
disposable camera sleeve over the camera head.