Fig. 1.

a) Fraction of users that use a given technique. The pattern of each column indicates the technique, The colour of each column segment indicates the percentage of patients receiving gated/tracked treatment. Respondents could use more than one technique per treatment site. A substantial number of respondents reported using tracking but it was unclear if tracking was meant as monitoring only. b) Fraction of users that use given selection criteria to decide to treat patients with gating or tracking. Respondents could use more than one criterion per treatment site.