Radiosurgery of multiple brain metastases with single-isocenter dynamic conformal arcs (SIDCA)

Huang, Yimei; Chin, K; Robbins, Jared R.; Kim, Jinkoo; Li, Haisen; Amro, H.; Chetty, Indrin J.; Gordon, J; Ryu, Samuel

doi:10.1016/j.radonc.2014.05.009

Cited by 76 publications

(73 citation statements)

References 20 publications

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“…[15][16][17] Although the selected cases in the present article were challenging by design, as shown in Table 3, we found reasonable agreement with other published data reported on radiation therapy delivery to multiple targets. 1,2,15,16,18 As seen in Table 3, the literature results generally fell within or very close to the 95% prediction band based on the model presented in Figure 3. Of particular note were the results by Ma et al 15 and McDonald et al, 16 which indicated for specific cases a volume of normal brain receiving 60% and 50% of the prescription dose higher than the upper limit of our model's 95% prediction band.…”

Section: Discussionsupporting

confidence: 67%

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Investigation of two linear accelerator head designs for treating brain metastases with hypofractionated volumetric-modulated arc radiotherapy

Ruschin

Sahgal

Iradji

et al. 2016

BJR

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Objective: To investigate brain radiation dose in complex cases arising from two stereotactic linear accelerator designs and to present a method for comparing brain dose to published data. Methods: Two head designs were considered: Beam Modulator (BM) and Agility (AG). 12 patients treated on BM were replanned with AG. Planning objectives were: minimize brain dose and satisfy target coverage and organs at risk dose constraints. Each of the 36 targets was analyzed for conformality index (CI Paddick), gradient index (GI) and homogeneity index (HI). Total volume of tissue receiving 80% (V80) of the prescription dose down to 25% (V25) was evaluated. Similarly the volume of brain minus planning target volume receiving 80% (BMP80) down to 25% (BMP25) was evaluated. The mean brain dose and BMP dose were also evaluated. System differences were statistically evaluated using Wilcoxon signed-rank test. Powerlaw models for total volume (V) and brain minus planning target volumes (BMP) were generated based on BM data.Results: The median CI Paddick was 0.74 and 0.76 for BM and AG, respectively (p 5 0.04). The median GI was 5.5 and 6.1 (p , 0.01) and the median HI was 1.17 and 1.16 for BM and AG, respectively (p , 0.01). Neither V or BMP receiving doses of 80% down to 40% exhibited statistically significant difference between the two systems, whereas the volume of brain minus PTV receiving 25% (BMP25) was weakly different (p 5 0.02). AG exhibited a lower mean BMP dose (4.1 Gy) than BM (4.6 Gy) (p , 0.01). Power-law models for V/BMP showed excellent (R 2 . 0.80) agreement for the dose levels studied and comparable results with published data. Conclusion: Treatment plans of equivalent quality were attained with AG compared with BM. Advances in knowledge: The AG system involves a novel collimation design. The present article demonstrates equivalent or improved brain dose for complex, multitarget cases using AG vs an older stereotactic system. INTRODUCTIONThe use of intensity-modulated radiotherapy or volumetricmodulated arc radiotherapy (VMAT) using multileaf collimators (MLCs) for stereotactic radiosurgery and radiotherapy is becoming increasingly popular, as this technique affords efficient delivery with a high degree of target conformality. [1][2][3] In particular, for multiple targets, the use of VMAT has been implicated in yielding shorter treatment times while providing comparable plan quality to intensity-modulated radiotherapy and three-dimensional conformal treatments. 1 Initial experiences with VMAT were with multi-isocentre plans, 4,5 followed by a series of studies investigating the feasibility of a singleisocentre approach. 2,6

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Section: Discussionsupporting

confidence: 67%

“…Huang et al 18 Table 3, the TPS itself likely plays an influential role in determining brain dose. In the present study, we observed that the TPS optimization engine produced undesirable segments for multiple targets (Figure 4).…”

Section: Discussionmentioning

confidence: 99%

Investigation of two linear accelerator head designs for treating brain metastases with hypofractionated volumetric-modulated arc radiotherapy

Ruschin

Sahgal

Iradji

et al. 2016

BJR

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“…The multileaf collimators' (MLC) leaf resolution is also improving, with 2.5 mm leaf widths at the isocenter, in order to improve the dose conformality to the target (12) . Treatment delivery methods have advanced to further improve conformality to complex geometric targets, while limiting dose to critical organs, such as dynamic conformal arc (DCA), Intensity Modulated Radiation Therapy (IMRT), and Volumetric Modulated Arc Therapy (VMAT) 13 , 14 , 15 , 16 . In the era of image guidance, numerous methods have been developed for stereotactic treatment delivery, including optical surface monitoring, in‐room CT, stereoscopic X‐ray imaging, ultrasound, and cone‐beam computed tomography (CBCT) 17 , 18 , 19 , 20 .…”

Section: Introductionmentioning

confidence: 99%

Characteristics of a novel treatment system for linear accelerator–based stereotactic radiosurgery

Song

Chin-Snyder

et al. 2015

J Applied Clin Med Phys

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The purpose of this study is to characterize the dosimetric properties and accuracy of a novel treatment platform (Edge radiosurgery system) for localizing and treating patients with frameless, image‐guided stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). Initial measurements of various components of the system, such as a comprehensive assessment of the dosimetric properties of the flattening filter‐free (FFF) beams for both high definition (HD120) MLC and conical cone‐based treatment, positioning accuracy and beam attenuation of a six degree of freedom (6DoF) couch, treatment head leakage test, and integrated end‐to‐end accuracy tests, have been performed. The end‐to‐end test of the system was performed by CT imaging a phantom and registering hidden targets on the treatment couch to determine the localization accuracy of the optical surface monitoring system (OSMS), cone‐beam CT (CBCT), and MV imaging systems, as well as the radiation isocenter targeting accuracy. The deviations between the percent depth‐dose curves acquired on the new linac‐based system (Edge), and the previously published machine with FFF beams (TrueBeam) beyond Dmax were within 1.0% for both energies. The maximum deviation of output factors between the Edge and TrueBeam was 1.6%. The optimized dosimetric leaf gap values, which were fitted using Eclipse dose calculations and measurements based on representative spine radiosurgery plans, were 0.700 mm and 1.000 mm, respectively. For the conical cones, 6X FFF has sharper penumbra ranging from 1.2−1.8 mm (80%‐20%) and 1.9−3.8 mm (90%‐10%) relative to 10X FFF, which has 1.2−2.2 mm and 2.3−5.1 mm, respectively. The relative attenuation measurements of the couch for PA, PA (rails‐in), oblique, oblique (rails‐out), oblique (rails‐in) were: −2.0%, −2.5%, −15.6%, −2.5%, −5.0% for 6X FFF and −1.4%, −1.5%, −12.2%, −2.5%, −5.0% for 10X FFF, respectively, with a slight decrease in attenuation versus field size. The systematic deviation between the OSMS and CBCT was −0.4±0.2 mm, 0.1±0.3 mm, and 0.0±0.1 mm in the vertical, longitudinal, and lateral directions. The mean values and standard deviations of the average deviation and maximum deviation of the daily Winston‐Lutz tests over three months are 0.20±0.03 mm and 0.66±0.18 mm, respectively. Initial testing of this novel system demonstrates the technology to be highly accurate and suitable for frameless, linac‐based SRS and SBRT treatment.PACS number: 87.56.J‐

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“…The most recent commercial implementation (HyperArc, Varian Medical Systems) offers refinements in terms of planning automation and collision prevention 10. Alternatively, Huang et al11 proposed a concept of single isocenter dynamic conformal arcs (SIDCA), whereby each lesion is treated by a dedicated group of dynamic conformal arcs but all groups share the same isocenter positioned between all targets. This allows for more efficient dynamic arc treatment, as only one isocenter setup is necessary, and the couch angles and arc directions can be optimized for fastest delivery.…”

Section: Introductionmentioning

confidence: 99%

A hybrid volumetric dose verification method for single‐isocenter multiple‐target cranial SRS

Ahmed

Kapatoes

Zhang

et al. 2018

J Applied Clin Med Phys

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A commercial semi‐empirical volumetric dose verification system (PerFraction [PF], Sun Nuclear Corp.) extracts multi‐leaf collimator positions from the electronic portal imaging device movies collected during a pre‐treatment run, while the rest of the delivered control point information is harvested from the accelerator log files. This combination is used to reconstruct dose on a patient CT dataset with a fast superposition/convolution algorithm. The method was validated for single‐isocenter multi‐target SRS VMAT treatments against absolute radiochromic film measurements in a cylindrical phantom. The targets ranged in size from 0.8 to 3.6 cm and in number from 3 to 10 per plan. A total of 17 films rotated at different angles around the cylinder axis were analyzed. Each of 27 total targets was intercepted by at least one film, and 2–4 different films were analyzed per plan. Film dose was always scaled to the ion chamber measurement in a high‐dose, low‐gradient area deliberately created at the isocenter. The planar dose agreement between PF and film using 3%(Global dose‐difference normalization)/1 mm gamma analysis was on average 99.2 ± 1.1%. The point dose difference in the low‐gradient area in the middle of every target was below 3%, while PF‐reconstructed and film dose centroids for individual targets showed submillimeter agreement when measured on a well aligned accelerator. Volumetrically, all voxels in all plans agreed between PF and the primary treatment planning system at the 3%/1 mm level. With proper understanding of its advantages and shortcomings, the tool can be applied to patient‐specific QA in routine radiosurgical clinical practice.

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Radiosurgery of multiple brain metastases with single-isocenter dynamic conformal arcs (SIDCA)

Cited by 76 publications

References 20 publications

Investigation of two linear accelerator head designs for treating brain metastases with hypofractionated volumetric-modulated arc radiotherapy

Investigation of two linear accelerator head designs for treating brain metastases with hypofractionated volumetric-modulated arc radiotherapy

Characteristics of a novel treatment system for linear accelerator–based stereotactic radiosurgery

A hybrid volumetric dose verification method for single‐isocenter multiple‐target cranial SRS

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