Image artifacts in early TV

[Rinehart]

I found these photos on Steve Restelli's web site historytv.net. They are from Vladimir Zworykin's personal collection of pictures taken of early television broadcasts. There are about sixteen or so in total, most of them show the characteristic faults of iconoscope cameras: edge flaring, shading problems, etc. But these also show curved lines radiating from the edge to the centre. Mr. Restelli tells me that they are on the original photographs, although scanning has accentuated them. He doesn't know what caused them. I've looked through the section on image defects in Fink, but they don't look like any of the examples there. Can anyone hazard a guess at what they might be?