Comparison of megavoltage position verification for prostate irradiation based on bony anatomy and implanted fiducials

A Comparison of the Use of Bony Anatomy and Internal Markers for Offline Verification and an Evaluation of the Potential Benefit of Online and Offline Verification Protocols for Prostate Radiotherapy

“…It will have more effect in some patients than others as the majority of events >5mm in the posterior direction occurred in five patients out of the cohort of 30. Nederveen et al also found that the use of a bony anatomy protocol increased the set-up error in six patients out of a cohort of 23 (13).…”

“…In the group of 30 patients without the balloon the systematic displacements were reduced by 44% ,58% , 62% which is a comparable with our study. Nederveen et al (13) used the shrinking action level protocol (SAL) and the systematic error reduced from 2.4mm, 4.4mm and 3.7mm to 0.6mm, 0.9mm and 0.6mm in the RL, SI and AP direction respectively. This is a much smaller systematic error than seen here but involved a greater workload.…”

“…Cone beam CT is being explored but involves purchasing additional equipment for each linear accelerator and increased time on the treatment unit. An alternative approach, which is already routine in clinical practice in several centres (11,12,13,14,15) is to use fiducial marker seeds implanted within the prostate.…”

Impact of the observers' experience on daily prostate localization accuracy in ultrasound‐based IGRT with the Clarity platform

“…Direct imaging of the prostate gland and daily verification of its position during each treatment session is essential for reducing the margins and, consequently, avoiding the organs at risk such as rectum and bladder. Several image guidance methods have been investigated in recent years, including tumor tracking with intraprostatic fiducial markers, cone‐beam computed tomography (CBCT), and ultrasound‐based imaging (US‐image guidance) 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 . Ultrasound‐based systems are volumetric and offer better soft‐tissue visualization compared to CBCT, without additional exposure to ionizing radiations (9) .…”

Intensity-modulated radiation therapy: emerging cancer treatment technology

“…In recent years, transabdominal ultrasound systems have been employed to more accurately target the prostate on a daily basis (Lattanzi et al, 1999;Lattanzi et al, 2000;D'Amico et al, 2001). As an alternative, the implantation of small metal seeds into the prostate to serve as fiduciaries during daily portal imaging has also proven reliable as a means of reproducibly localising the prostate (Nederveen et al, 2003). In addition, it has been demonstrated that the use of a rectal balloon catheter can immobilise the prostate and facilitate localisation on port films potentially allowing tighter margins for the treatment volume (Wachter et al, 2002).…”