Table 3 Intra-fraction motion (IFM) in various series

Present series (n = 46)

Supine, knee cushion. Comfortably full bladder, empty rectum.

3 fiducial markers, imaged with aSi EPID. IFM estimated by comparing during-treatment EPI isocenter position with presumed pre-treatment position (after any correction; not verified by a repeat EPI).

Cheung [7] (n = 33)

Custom vacuum lock bag. Empty bladder and rectum.

3 fiducial markers, imaged with EPID. IFM estimated by comparing pre and post-treatment EPIs on days 1 to 9 of phase I.

Aubry [8] (n = 18)

Supine, immobilization not stated. Full bladder, empty rectum.

2 - 3 implanted fiducial markers. Multiple daily sets of portal images to estimate intrafraction motion. IFM was < 5 mm in 100%, 99.5% and 99% of cases along L - R, S - I and A - P axes respectively.

Chung [9] (n = 17)

Supine, custom vacuum lock bag, standard leg immobilizing device. Comfortably full bladder, empty rectum.

3 implanted fiducial markers. Lateral portal images prior to treatment. Correction of isocenter placement errors > 3 mm in any direction. Post-correction EPI to confirm correction.

J Wu [10] (n = 13)

Supine, alpha cradle, soft foam immobilization device supporting lower legs. Partially full bladder, empty rectum.

3 implanted fiducial markers. Daily EPI to confirm field placement. 3 × weekly lateral port films to measure random and systematic field placement errors. Data shown are with respect to center of mass.

Letourneau [11] (n = 8)

Not stated

3 implanted fiducial markers. Initial set-up according to skin marks, then cone beam CT verification of marker position and correction as required, followed by repeat cone beam CT for confirmation. Movement of markers relative to bony landmarks was assessed with kV x-rays; shown are standard deviations of IFM based on first and last radiographs that were taken between the 2 cone beam CTs, approximately 15 - 25 minutes apart.

Nederveen [12] (n = 10)

Supine, knee cushion. Empty bladder; no bowel instructions.

Real-time aSi "movies" showing movement of fiducial markers within the prostate over a 2 - 3 minute period.

Litzenberg [13] (n = 11)

Supine, flat couch, knee support. No bladder or bowel instructions.

3 electromagnetic transponders (Calypso^®) implanted in the prostate. Monitoring of position of transponders for 8 minutes.

Ghilezan [14] (n = 6)

Supine, no immobilization. Empty bladder, full rectum.

Sagittal cine-MRI at 6 sec intervals over 1 hour on 3 days. Measured movement was in sagittal plane; no distinction between A - P and S - I axes. Rectal filling based on qualitative assessment of the amount of gas and feces in the rectum on a particular scan.

As above, empty rectum.

Huang [15] (n = 20)

Supine. No additional details.

BAT ultrasound images before and after treatment. IFM was < 5 mm in 100%, 99.5% and 99% of cases along L - R, S - I and A - P axes respectively.

Stroom [16] (n = 15) a) Supine

Supine, knee roll, foot support. Suppository prior to planning CT; partially full bladder for all CTs.

Planning CT, 3 repeat CTs, at 2, 4 and 6 weeks of treatment. Changes in CTV position relative to bony anatomy were compared on the 4 CT datasets to estimate IFM.

Stroom [16] (n = 15) b) Prone

Prone with belly board. Otherwise as above.

As above.