Debbie,
For the PET portion of the scan (which takes a long time) you do NOT go in and out (on the 3 different machines they used on me). What is happening it advances you by 10cm or so. I counted to 140 to 180 for each segment.
Compared to IMRT this is nothing although it does seem to take forever.

Markus


Partial glossectomy (25%) anterior tongue. 4/6/07/. IMRT start @5/24/07 (3x) Erbitux start/end@ 5/24/07. IMRT wider field (30x) start 6/5/07. Weekly cisplatin (2x30mg/m2), then weekly carbo- (5x180mg/m2). End of Tx 19 July 07.