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Wilhelm ML, Chan MKH, Abel B, Cremers F, Siebert FA, Wurster S, Krug D, Wolff R, Dunst J, Hildebrandt G, Schweikard A, Rades D, Ernst F, Blanck O. Tumor-dose-rate variations during robotic radiosurgery of oligo and multiple brain metastases. Strahlenther Onkol 2020; 197:581-591. [PMID: 32588102 PMCID: PMC8219559 DOI: 10.1007/s00066-020-01652-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 06/02/2020] [Indexed: 12/31/2022]
Abstract
Purpose For step-and-shoot robotic stereotactic radiosurgery (SRS) the dose delivered over time, called local tumor-dose-rate (TDR), may strongly vary during treatment of multiple lesions. The authors sought to evaluate technical parameters influencing TDR and correlate TDR to clinical outcome. Material and methods A total of 23 patients with 162 oligo (1–3) and multiple (>3) brain metastases (OBM/MBM) treated in 33 SRS sessions were retrospectively analyzed. Median PTV were 0.11 cc (0.01–6.36 cc) and 0.50 cc (0.12–3.68 cc) for OBM and MBM, respectively. Prescription dose ranged from 16 to 20 Gy prescribed to the median 70% isodose line. The maximum dose-rate for planning target volume (PTV) percentage p in time span s during treatment (TDRs,p) was calculated for various p and s based on treatment log files and in-house software. Results TDR60min,98% was 0.30 Gy/min (0.23–0.87 Gy/min) for OBM and 0.22 Gy/min (0.12–0.63 Gy/min) for MBM, respectively, and increased by 0.03 Gy/min per prescribed Gy. TDR60min,98% strongly correlated with treatment time (ρ = −0.717, p < 0.001), monitor units (MU) (ρ = −0.767, p < 0.001), number of beams (ρ = −0.755, p < 0.001) and beam directions (ρ = −0.685, p < 0.001) as well as lesions treated per collimator (ρ = −0.708, P < 0.001). Median overall survival (OS) was 20 months and 1‑ and 2‑year local control (LC) was 98.8% and 90.3%, respectively. LC did not correlate with any TDR, but tumor response (partial response [PR] or complete response [CR]) correlated with all TDR in univariate analysis (e.g., TDR60min,98%: hazard ration [HR] = 0.974, confidence interval [CI] = 0.952–0.996, p = 0.019). In multivariate analysis only concomitant targeted therapy or immunotherapy and breast cancer tumor histology remained a significant factor for tumor response. Local grade ≥2 radiation-induced tissue reactions were noted in 26.3% (OBM) and 5.2% (MBM), respectively, mainly influenced by tumor volume (p < 0.001). Conclusions Large TDR variations are noted during MBM-SRS which mainly arise from prolonged treatment times. Clinically, low TDR corresponded with decreased local tumor responses, although the main influencing factor was concomitant medication.
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Affiliation(s)
- Maria-Lisa Wilhelm
- Department of Radiation Oncology, University Medicine Rostock, Rostock, Germany.,Saphir Radiosurgery Center Frankfurt and Northern Germany, Guestrow, Germany
| | - Mark K H Chan
- Department of Radiation Oncology, Karl-Lennert-Krebscentrum Nord, University Medical Center Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, Haus 50, 24105, Kiel, Germany.,Strahlenklinik, University Hospital Essen, Hufelandstr. 55, Essen, Germany
| | - Benedikt Abel
- Institute for Robotics and Cognitive Systems, University of Luebeck, Luebeck, Germany
| | - Florian Cremers
- Department of Radiation Oncology, University Medical Center Schleswig-Holstein, Luebeck, Germany
| | - Frank-Andre Siebert
- Department of Radiation Oncology, Karl-Lennert-Krebscentrum Nord, University Medical Center Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, Haus 50, 24105, Kiel, Germany
| | - Stefan Wurster
- Saphir Radiosurgery Center Frankfurt and Northern Germany, Guestrow, Germany.,Department of Radiation Oncology, University Medicine Greifswald, Greifswald, Germany
| | - David Krug
- Saphir Radiosurgery Center Frankfurt and Northern Germany, Guestrow, Germany.,Department of Radiation Oncology, Karl-Lennert-Krebscentrum Nord, University Medical Center Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, Haus 50, 24105, Kiel, Germany
| | - Robert Wolff
- Saphir Radiosurgery Center Frankfurt and Northern Germany, Guestrow, Germany.,Department of Neurosurgery, University Hospital Frankfurt, Frankfurt, Germany
| | - Jürgen Dunst
- Department of Radiation Oncology, Karl-Lennert-Krebscentrum Nord, University Medical Center Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, Haus 50, 24105, Kiel, Germany
| | - Guido Hildebrandt
- Department of Radiation Oncology, University Medicine Rostock, Rostock, Germany
| | - Achim Schweikard
- Institute for Robotics and Cognitive Systems, University of Luebeck, Luebeck, Germany
| | - Dirk Rades
- Department of Radiation Oncology, University Medical Center Schleswig-Holstein, Luebeck, Germany
| | - Floris Ernst
- Institute for Robotics and Cognitive Systems, University of Luebeck, Luebeck, Germany
| | - Oliver Blanck
- Saphir Radiosurgery Center Frankfurt and Northern Germany, Guestrow, Germany. .,Department of Radiation Oncology, Karl-Lennert-Krebscentrum Nord, University Medical Center Schleswig-Holstein, Campus Kiel, Arnold-Heller-Straße 3, Haus 50, 24105, Kiel, Germany.
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Rijken J, Bhat M, Crowe S, Kairn T, Trapp J. Linear accelerator bunker shielding for stereotactic radiotherapy. Phys Med Biol 2019; 64:21NT04. [PMID: 31569089 DOI: 10.1088/1361-6560/ab4916] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Shielding protocols such as NCRP 151, IAEA SRS 47 and IPEM 47 are commonly used for the design of radiotherapy facilities. Some work has been accomplished in updating the basic formula with the advent of IMRT but little consideration has been made for unflattened beams and stereotactic techniques apart from for facilities housing devices like the CyberKnife. The inevitable scenario of a stereotactic-only linear accelerator was considered in this study. The necessary shielding requirements were determined based on stereotactic data from a year's worth treatments from one clinic as well as further measurements of leakage, scatter and use factors. These values were compared to recommendations in the literature. While tenth value layer amounts, workload and barrier widths could be kept at the status quo, major changes could be made to the parameters of leakage, scatter and use factors while still maintaining safety. Some differences could also be seen for the use of IMRT factors. Current shielding protocols were found to inadequately describe methodology for the shielding of a stereotactic-only radiotherapy linac bunker, producing overly-conservative wall thicknesses which is in disagreement with the principles of ICRP.
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Affiliation(s)
- James Rijken
- GenesisCare, Flinders Private Hospital, Bedford Park, SA, Australia. Queensland University of Technology, Brisbane, QLD, Australia. Author to whom any correspondence should be addressed
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Ueda Y, Ohira S, Yamazaki H, Mabuchi N, Higashinaka N, Miyazaki M, Teshima T. Dosimetric performance of two linear accelerator-based radiosurgery systems to treat single and multiplebrain metastases. Br J Radiol 2019; 92:20190004. [PMID: 31188018 DOI: 10.1259/bjr.20190004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To evaluate and compare the dosimetric plan quality for noncoplanar volumetric arc therapy of single and multiple brain metastases using the linear accelerator-based radiosurgery system HyperArc and a robotic radiosurgery system. METHODS 31 tumors from 24 patients were treated by stereotactic radiosurgery using the CyberKnife system. CT images, structure sets, and dose files were transferred to the Eclipse treatment planning system for the HyperArc system. Dosimetric parameters for both plans were compared. The beam-on time was calculated from the total monitor unit and dose rate. RESULTS For normal brain tissue, the received volume doses were significantly lower for HyperArc than for CyberKnife_G4 and strongly correlated with the planning target volume (PTV) for cases of single brain metastasis. In addition, the difference in volume dose between CyberKnife_G4 and HyperArc was proportional to the PTV. For multiple brain metastases, no significant difference was observed between the two stereotactic radiosurgery systems, except for high-dose region in the normal tissue. In low dose for brain minus PTV, when the maximum distance among each target was above 8.0 cm, HyperArc delivered higher dose than CyberKnife_G4. The mean ± SDs for the beam-on time were 15.8 ± 5.3 and 5.6 ± 0.8 min for CyberKnife_G4 and HyperArc, respectively (p < .01). CONCLUSION HyperArc is best suited for larger targets in single brain metastasis and for smaller inter tumor tumor distances in multiple brain metastases. ADVANCES IN KNOWLEDGE The performance of HyperArc in comparison with CyberKnife_G4 was depended on defined margin and tumor distances.
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Affiliation(s)
- Yoshihiro Ueda
- 1 Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Shingo Ohira
- 1 Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Hideya Yamazaki
- 2 Department of Radiation Oncology, Soseikai General Hospital CyberKnife Center, Kyoto, Japan
| | - Nobuhisa Mabuchi
- 2 Department of Radiation Oncology, Soseikai General Hospital CyberKnife Center, Kyoto, Japan
| | - Naokazu Higashinaka
- 2 Department of Radiation Oncology, Soseikai General Hospital CyberKnife Center, Kyoto, Japan
| | - Masayoshi Miyazaki
- 1 Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Teruki Teshima
- 1 Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
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