scholarly journals Dosimetric performance of two linear accelerator-based radiosurgery systems to treat single and multiplebrain metastases

2019 ◽  
Vol 92 (1100) ◽  
pp. 20190004 ◽  
Author(s):  
Yoshihiro Ueda ◽  
Shingo Ohira ◽  
Hideya Yamazaki ◽  
Nobuhisa Mabuchi ◽  
Naokazu Higashinaka ◽  
...  
Keyword(s):  
Brain Metastasis ◽  
Brain Metastases ◽  
Stereotactic Radiosurgery ◽  
Linear Accelerator ◽  
Planning System ◽  
Treatment Planning System ◽  
Multiple Brain Metastases ◽  
Volumetric Arc Therapy ◽  
Significant Difference ◽  
Single Brain Metastasis

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.

scholarly journals Point dose verification of Cranial Stereotactic Radiosurgery using micro Ionization Chamber and EBT3 film for 6MV FF and FFF beams in Varian TrueBeam® LINAC

2020 ◽  
Vol 26 (3) ◽  
pp. 135-142
Author(s):  
Gopinath Mamballikalam ◽  
S. Senthilkumar ◽  
Basith P.M. Ahamed ◽  
Rohit Inipully ◽  
P.M. Jayadevan ◽  
...  
Keyword(s):  
Stereotactic Radiosurgery ◽  
Planning System ◽  
Treatment Planning System ◽  
Patient Specific ◽  
Small Lesion ◽  
Dose Verification ◽  
Gafchromic Film ◽  
Volumetric Arc Therapy ◽  
Significant Difference ◽  
Flattening Filter

AbstractIntroduction: Achieving high positional and dosimetric accuracy in small fields is very challenging due to the imbalance of charged particle equilibrium (CPE), occlusion of the primary radiation source, and overlapping penumbra regions. These factors make the choice of the detector for Stereotactic Radiosurgery (SRS) patient-specific quality assurance (PSQA) difficult. The aim of the study is to compare the suitability of EBT3 Gafchromic film against CC01 pinpoint chamber for the purpose of SRS and stereotactic Radiotherapy (SRT) dose verification.Material and Method: EBT3 Gafchromic film was calibrated against Treatment Planning System (TPS) doses (1 Gy – 35 Gy). CC01 pinpoint chamber and EBT3 film was used to verify Patient-Specific point doses of 21 intracranial lesions each planned with Static, Dynamic Conformal Arc (DCA), and Volumetric Arc Therapy (VMAT) using Varian TrueBeam Accelerator 6MV Flattening Filter (FF) and 6MV Flattening Filter Free (FFF) beams. The lesion sizes varied from 0.4 cc to 2.9 cc. The lesions were categorized into <1cc, 1cc-2cc and 2cc-3cc.Results: High variations in measured doses from TPS calculated dose were observed with small lesion volumes irrespective of the dosimeter. As the sizes decreased high uncertainty was observed in ion chamber results. CC01 was observed under-responding to film in small lesion sizes (<1cc), where nearly 50% of results under-responded in comparison with Film results. Film results were more or less consistent for static and DCA plans. Static and DCA plans were consistent passing more than 73% of the plans of the smallest lesion size category. VMAT showed very poor PSQA agreement for all three volumes (32.1% for <1cc, 14.3% for 2cc-3cc and 39.3% for 2cc-3cc). No significant difference was observed between 6MVFF and 6MVFFF beams from the chi-squared test.Conclusion: EBT3 Film was observed to be a more suitable detector for small lesion sizes less than 1cc, compared to CC01. As the volume increases, the response of CC01 and EBT3 film have no significant difference in performing PSQA for intracranial SRS/SRT. VMAT techniques for intra cranial SRS shows deviation from TPS planned dose for both EBT3 film and CC01 and should not be preferred choice of verification tools.

Dosimetric comparison of fractionated radiosurgery plans using frameless Gamma Knife ICON and CyberKnife systems with linear accelerator–based radiosurgery plans for multiple large brain metastases

2020 ◽  
Vol 132 (5) ◽  
pp. 1473-1479 ◽  
Author(s):  
Eun Young Han ◽  
He Wang ◽  
Dershan Luo ◽  
Jing Li ◽  
Xin Wang
Keyword(s):  
Brain Metastases ◽  
Gamma Knife ◽  
Linear Accelerator ◽  
Treatment Time ◽  
Target Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Normal Brain ◽  
Large Brain ◽  
The Mean

OBJECTIVEFor patients with multiple large brain metastases with at least 1 target volume larger than 10 cm3, multifractionated stereotactic radiosurgery (MF-SRS) has commonly been delivered with a linear accelerator (LINAC). Recent advances of Gamma Knife (GK) units with kilovolt cone-beam CT and CyberKnife (CK) units with multileaf collimators also make them attractive choices. The purpose of this study was to compare the dosimetry of MF-SRS plans deliverable on GK, CK, and LINAC and to discuss related clinical issues.METHODSTen patients with 2 or more large brain metastases who had been treated with MF-SRS on LINAC were identified. The median planning target volume was 18.31 cm3 (mean 21.31 cm3, range 3.42–49.97 cm3), and the median prescribed dose was 27.0 Gy (mean 26.7 Gy, range 21–30 Gy), administered in 3 to 5 fractions. Clinical LINAC treatment plans were generated using inverse planning with intensity modulation on a Pinnacle treatment planning system (version 9.10) for the Varian TrueBeam STx system. GK and CK planning were retrospectively performed using Leksell GammaPlan version 10.1 and Accuray Precision version 1.1.0.0 for the CK M6 system. Tumor coverage, Paddick conformity index (CI), gradient index (GI), and normal brain tissue receiving 4, 12, and 20 Gy were used to compare plan quality. Net beam-on time and approximate planning time were also collected for all cases.RESULTSPlans from all 3 modalities satisfied clinical requirements in target coverage and normal tissue sparing. The mean CI was comparable (0.79, 0.78, and 0.76) for the GK, CK, and LINAC plans. The mean GI was 3.1 for both the GK and the CK plans, whereas the mean GI of the LINAC plans was 4.1. The lower GI of the GK and CK plans would have resulted in significantly lower normal brain volumes receiving a medium or high dose. On average, GK and CK plans spared the normal brain volume receiving at least 12 Gy and 20 Gy by approximately 20% in comparison with the LINAC plans. However, the mean beam-on time of GK (∼ 64 minutes assuming a dose rate of 2.5 Gy/minute) plans was significantly longer than that of CK (∼ 31 minutes) or LINAC (∼ 4 minutes) plans.CONCLUSIONSAll 3 modalities are capable of treating multiple large brain lesions with MF-SRS. GK has the most flexible workflow and excellent dosimetry, but could be limited by the treatment time. CK has dosimetry comparable to that of GK with a consistent treatment time of approximately 30 minutes. LINAC has a much shorter treatment time, but residual rotational error could be a concern.

scholarly journals Linear accelerator stereotactic radiosurgery and radiotherapy for multiple brain metastases: outcomes from a tertiary centre

2018 ◽  
Vol 20 (suppl_5) ◽  
pp. v355-v355
Author(s):  
Dr Mark O’Beirn ◽  
Dr Paul Sanghera ◽  
Mr Peter Nightingale ◽  
Dr Sara Meade ◽  
Dr Andrew Hartley ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Stereotactic Radiosurgery ◽  
Linear Accelerator ◽  
Multiple Brain Metastases ◽  
Tertiary Centre

Gamma Knife surgery for multiple brain metastases from a malignant schwannoma of the penis

2006 ◽  
Vol 105 (Supplement) ◽  
pp. 238-240 ◽  
Author(s):  
Albertus T. C. J. van Eck ◽  
Gerhard A. Horstmann
Keyword(s):  
Brain Metastasis ◽  
Brain Metastases ◽  
Gamma Knife ◽  
De Novo ◽  
Tumor Resection ◽  
Gamma Knife Surgery ◽  
Malignant Schwannoma ◽  
Efficacy And Safety ◽  
Single Brain Metastasis ◽  
Therapy Option

✓The occurrence of brain metastases from a malignant schwannoma of the penis is extremely rare. In patients with a single brain metastasis, microsurgical extirpation is the treatment of choice and verifies the diagnosis. In cases of multiple or recurrent metastases, radiosurgery is an effective and safe therapy option. Gamma Knife surgery was performed in a patient who had previously undergone tumor resection and who presented with recurrence of the lesion and three de novo brain metastases. This first report on brain metastasis from a malignant penile schwannoma illustrates the efficacy and safety of radiosurgical treatment for these tumors.

Management of multiple brain metastases via dual-isocenter VMAT stereotactic radiosurgery

2021 ◽  
Author(s):  
Allison N Palmiero ◽  
Denise Fabian ◽  
William St Clair ◽  
Marcus Randall ◽  
Damodar Pokhrel
Keyword(s):  
Brain Metastases ◽  
Stereotactic Radiosurgery ◽  
Multiple Brain Metastases

Surgical treatment of multiple brain metastases

1993 ◽  
Vol 79 (2) ◽  
pp. 210-216 ◽  
Author(s):  
Rajesh K. Bindal ◽  
Raymond Sawaya ◽  
Milam E. Leavens ◽  
J. Jack Lee
Keyword(s):  
Brain Metastases ◽  
Survival Time ◽  
Prognostic Indicators ◽  
Survival Duration ◽  
Surgical Removal ◽  
Complication Rates ◽  
Multiple Brain Metastases ◽  
Significant Difference ◽  
Group A ◽  
Group B

✓ The authors conducted a retrospective review of the charts of 56 patients who underwent resection for multiple brain metastases. Of these, 30 had one or more lesions left unresected (Group A) and 26 underwent resection of all lesions (Group B). Twenty-six other patients with a single metastasis who underwent resection (Group C) were selected to match Group B by type of primary tumor, time from first diagnosis of cancer to diagnosis of brain metastases, and presence or absence of systemic cancer at the time of surgery. Statistical analysis indicated that Groups A and B were also homogeneous for these prognostic indicators. Median survival duration was 6 months for Group A, 14 months for Group B, and 14 months for Group C. There was a statistically significant difference in survival time between Groups A and B (p = 0.003) and Groups A and C (p = 0.012) but not between Groups B and C (p > 0.5). Brain metastasis recurred in 31% of patients in Group B and in 35% of those in Group C; this difference was not significant (p > 0.5). Symptoms improved after surgery in 65% of patients in Group A, 83% in Group B, and 84% in Group C. Symptoms worsened in 13% of patients in Group A, 6% in Group B, and 0% in Group C. Groups A, B, and C had complication rates per craniotomy of 8%, 9%, and 8%, and 30-day mortality rates of 3%, 4%, and 0%, respectively. Guidelines for management of patients with multiple brain metastases are discussed. The authors conclude that surgical removal of all lesions in selected patients with multiple brain metastases results in significantly increased survival time and gives a prognosis similar to that of patients undergoing surgery for a single metastasis.

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