Читать книгу Leksell Radiosurgery - Группа авторов - Страница 45

•Treatment beam on time should be in the 30-min range. Mask preparation for hardening on the patient takes 10 min. Patient verification and two CBCT scans plus imaging reconstruction and verification of the treatment takes 20 min or more. Total mask on time even in the perfect patient cannot be less than 60 min assuming that no other motion detection CBCT are repeated.

•The need for speed may lead to less conformal dose planning or dose selection in order to reduce mask on time since other times are fixed.

•The mask is not suitable for targets in extreme locations, far inferior, far anterior or posterior in the cranial vault.

•Not suitable for restless, claustrophobic, anxious, sleeping, or confused patients.

•Not suitable for patients with beards or very long bushy hair, which prevents good mask fixation.

•Not suitable for obese patients with large abdomens or large breasts, as the motion detection system cannot detect the fiducial markers on either side of the patient’s head.

•No gamma angles (70 and 110°) available for an extreme target position