For many years, we were happy to see the beam shut off automatically after enough MU for the image were delivered. Then Varian had disabled it in VARiS/Vision Generation 6 (upgrade: Nov 2001), without apparent reason.

 

Now it is back again!

 

The situation had been a little confusing in the past 5 years: if an image template with a During-image had been added to the field on the Linac (the so-called 4D-Console), the beam would shut off automatically and the 4D-Console would present the image. But if the template was added in RT-Chart, the beam would not shut off. Instead, the Therapist would have to press Beam-Off manually after 15 MU or so, in order to see the image. This was an unpleasant thing, because you would have to remember where you added the image template ... Fortunately, this is history.