Bluetooth
Nothing negative can be said about Bluetooth operation. Regarding stability of connection, it is practically equivalent to a cable. The Connection Box was installed near the Gantry's stand, so the distance between the Box an DAVID was about 4 m. This gives good signal strength. PTW recommends distances up to 10-15 m.
Design
The chamber holder is depending on the linac vendor, so the following remarks are only valid for Varian linacs.
- The ODI (optical distance indicator) on our Varian linacs is blocked by DAVID. This means that if a therapist wants to check source skin distance, he/she has to pull out DAVID, do the check, and slide it back in. Not ideal.
- Grabbing DAVID's handle on the target side is easy, but on the gun side there should be something like a second handle for the other hand, to ensure a safe grip. Right now, the second hand supports the lower chamber window during manipulation, to keep DAVID from falling down.
- Initial vertical alignment of the chamber is accomplished with four adjustment screws. The adjustment worked out on our Clinacs, but the chamber is at the upmost position possible. The adjustment slits should be a little longer.
Software
- We would prefer to have the actual temperature displayed permanently in the status bar. This would give additional information about the degree of stabilization. Right now, the temperature is only displayed during a calibration mesurement.
- On Varian linacs, with the collimator at 0°, the target side leaf pair is #1, the gun side leaf pair is #40 (assuming 80-leaf MLC). In DAVID software (version 1.1), the "gun"/"target" labels are correct, but the leaf numbering is false:
We would flip the display, so that T and #1 are left, G and #40 are right.