Limits...
Variable dose interplay effects across radiosurgical apparatus in treating multiple brain metastases.

Ma L, Nichol A, Hossain S, Wang B, Petti P, Vellani R, Higby C, Ahmad S, Barani I, Shrieve DC, Larson DA, Sahgal A - Int J Comput Assist Radiol Surg (2014)

Bottom Line: All treatment plans were developed at individual centers, and the results were centrally analyzed.We found that dose-volume constraints were satisfied by each apparatus with some differences noted in certain structures such as the lens.Treatment times were shortest with TrueBeam FFF.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, University of California, San Francisco, 505 Parnassus Avenue, Room L-08, San Francisco, CA , 94143, USA, lijunma@radonc.ucsf.edu.

ABSTRACT

Purpose: Normal brain tissue doses have been shown to be strongly apparatus dependent for multi-target stereotactic radiosurgery. In this study, we investigated whether inter-target dose interplay effects across contemporary radiosurgical treatment platforms are responsible for such an observation.

Methods: For the study, subsets ([Formula: see text] and 12) of a total of 12 targets were planned at six institutions. Treatment platforms included the (1) Gamma Knife Perfexion (PFX), (2) CyberKnife, (3) Novalis linear accelerator equipped with a 3.0-mm multi-leaf collimator (MLC), and the (4) Varian Truebeam flattening-filter-free (FFF) linear accelerator also equipped with a 2.5 mm MLC. Identical dose-volume constraints for the targets and critical structures were applied for each apparatus. All treatment plans were developed at individual centers, and the results were centrally analyzed.

Results: We found that dose-volume constraints were satisfied by each apparatus with some differences noted in certain structures such as the lens. The peripheral normal brain tissue doses were lowest for the PFX and highest for TrueBeam FFF and CyberKnife treatment plans. Comparing the volumes of normal brain receiving 12 Gy, TrueBeam FFF, Novalis, and CyberKnife were 180-290 % higher than PFX. The mean volume of normal brain-per target receiving 4-Gy increased by approximately 3.0 cc per target for TrueBeam, 2.7 cc per target for CyberKnife, 2.0 cc per target for Novalis, and 0.82 cc per target for PFX. The beam-on time was shortest with the TrueBeam FFF (e.g., 6-9 min at a machine output rate of 1,200 MU/min) and longest for the PFX (e.g., 50-150 mins at a machine output rate of 350 cGy/min).

Conclusion: The volumes of normal brain receiving 4 and 12 Gy were higher, and increased more swiftly per target, for Linac-based SRS platforms than for PFX. Treatment times were shortest with TrueBeam FFF.

No MeSH data available.


Illustrations of four SRS modalities for the study: a Gamma Knife Perfexion b Cyberknife c Novalis DCA d Flattening filter free Truebeam. a was courtesy of Elekta (Atlanta, Georgia, USA)
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Fig1: Illustrations of four SRS modalities for the study: a Gamma Knife Perfexion b Cyberknife c Novalis DCA d Flattening filter free Truebeam. a was courtesy of Elekta (Atlanta, Georgia, USA)

Mentions: Following the same multi-institutional study protocol as per our previous publication, a multiple metastases SRS case was selected for independent treatment planning using the Gamma Knife PFX, CyberKnife, Novalis DCA delivery, and the TrueBeam FFF intensity-modulated arc delivery systems. An illustration of these modalities is given Fig. 1. In brief, subsets of target combination with 3, 6, 9, and 12 targets were selected for treatment planning using individual SRS modalities each housed in different institutions, which were chosen due to their expertise with the given technology. The spatial distribution of all the targets is shown in Fig. 2. For a robust comparison of the new TrueBeam FFF with the previously studied modalities, two independent institutions were used for planning with the TrueBeam FFF, each with their own treatment planning strategies.Fig. 1


Variable dose interplay effects across radiosurgical apparatus in treating multiple brain metastases.

Ma L, Nichol A, Hossain S, Wang B, Petti P, Vellani R, Higby C, Ahmad S, Barani I, Shrieve DC, Larson DA, Sahgal A - Int J Comput Assist Radiol Surg (2014)

Illustrations of four SRS modalities for the study: a Gamma Knife Perfexion b Cyberknife c Novalis DCA d Flattening filter free Truebeam. a was courtesy of Elekta (Atlanta, Georgia, USA)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4215114&req=5

Fig1: Illustrations of four SRS modalities for the study: a Gamma Knife Perfexion b Cyberknife c Novalis DCA d Flattening filter free Truebeam. a was courtesy of Elekta (Atlanta, Georgia, USA)
Mentions: Following the same multi-institutional study protocol as per our previous publication, a multiple metastases SRS case was selected for independent treatment planning using the Gamma Knife PFX, CyberKnife, Novalis DCA delivery, and the TrueBeam FFF intensity-modulated arc delivery systems. An illustration of these modalities is given Fig. 1. In brief, subsets of target combination with 3, 6, 9, and 12 targets were selected for treatment planning using individual SRS modalities each housed in different institutions, which were chosen due to their expertise with the given technology. The spatial distribution of all the targets is shown in Fig. 2. For a robust comparison of the new TrueBeam FFF with the previously studied modalities, two independent institutions were used for planning with the TrueBeam FFF, each with their own treatment planning strategies.Fig. 1

Bottom Line: All treatment plans were developed at individual centers, and the results were centrally analyzed.We found that dose-volume constraints were satisfied by each apparatus with some differences noted in certain structures such as the lens.Treatment times were shortest with TrueBeam FFF.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, University of California, San Francisco, 505 Parnassus Avenue, Room L-08, San Francisco, CA , 94143, USA, lijunma@radonc.ucsf.edu.

ABSTRACT

Purpose: Normal brain tissue doses have been shown to be strongly apparatus dependent for multi-target stereotactic radiosurgery. In this study, we investigated whether inter-target dose interplay effects across contemporary radiosurgical treatment platforms are responsible for such an observation.

Methods: For the study, subsets ([Formula: see text] and 12) of a total of 12 targets were planned at six institutions. Treatment platforms included the (1) Gamma Knife Perfexion (PFX), (2) CyberKnife, (3) Novalis linear accelerator equipped with a 3.0-mm multi-leaf collimator (MLC), and the (4) Varian Truebeam flattening-filter-free (FFF) linear accelerator also equipped with a 2.5 mm MLC. Identical dose-volume constraints for the targets and critical structures were applied for each apparatus. All treatment plans were developed at individual centers, and the results were centrally analyzed.

Results: We found that dose-volume constraints were satisfied by each apparatus with some differences noted in certain structures such as the lens. The peripheral normal brain tissue doses were lowest for the PFX and highest for TrueBeam FFF and CyberKnife treatment plans. Comparing the volumes of normal brain receiving 12 Gy, TrueBeam FFF, Novalis, and CyberKnife were 180-290 % higher than PFX. The mean volume of normal brain-per target receiving 4-Gy increased by approximately 3.0 cc per target for TrueBeam, 2.7 cc per target for CyberKnife, 2.0 cc per target for Novalis, and 0.82 cc per target for PFX. The beam-on time was shortest with the TrueBeam FFF (e.g., 6-9 min at a machine output rate of 1,200 MU/min) and longest for the PFX (e.g., 50-150 mins at a machine output rate of 350 cGy/min).

Conclusion: The volumes of normal brain receiving 4 and 12 Gy were higher, and increased more swiftly per target, for Linac-based SRS platforms than for PFX. Treatment times were shortest with TrueBeam FFF.

No MeSH data available.