Film-based delivery quality assurance for robotic radiosurgery: Commissioning and validation

Blanck, Oliver; Masi, Laura; Damme, Marie-Christin; Hildebrandt, Guido; Dunst, Jürgen; Siebert, Frank‐André; Poppinga, Daniela; Poppe, Björn

doi:10.1016/j.ejmp.2015.05.001

Cited by 33 publications

(59 citation statements)

References 27 publications

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“…The commissioning and validation for film based CyberKnife DQA using various test scenarios [7] was recently reported and results confirmed that, by means of accurate film-to-plan registration, maximum Gamma-Index pass-rate search and tight distance-to-agreement (DTA) criteria, small errors in beam delivery and system miscalibration can be detected. However, some drawbacks of film based methods applied to CyberKnife, remained unsolved: (1) absolute film dosimetry requires additional ion-chamber verification and appears to have an accuracy of no less than 3% [7] and (2) film DQA evaluation is cumbersome and requires long wait times (up to several hours) after irradiation. The generally long times required both to perform and analyze patient specific film DQA may significantly reduce the number of dosimetrically verified clinical treatment plans.…”

Section: Introductionsupporting

confidence: 55%

“…Radiochromic film measurement is the current method of choice both for routine QA as well as specific validation of patient treatment plans for the CyberKnife [6,7]. The commissioning and validation for film based CyberKnife DQA using various test scenarios [7] was recently reported and results confirmed that, by means of accurate film-to-plan registration, maximum Gamma-Index pass-rate search and tight distance-to-agreement (DTA) criteria, small errors in beam delivery and system miscalibration can be detected.…”

Section: Introductionmentioning

confidence: 99%

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High resolution ion chamber array delivery quality assurance for robotic radiosurgery: Commissioning and validation

Blanck

Masi²,

Chan

et al. 2016

Physica Medica

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Section: Introductionsupporting

confidence: 55%

Section: Introductionmentioning

confidence: 99%

High resolution ion chamber array delivery quality assurance for robotic radiosurgery: Commissioning and validation

Blanck

Masi²,

Chan

et al. 2016

Physica Medica

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“…Gamma‐index analysis 20 was used to compare the measurements and calculations, by applying a criterion of 3% local pixel dose difference (LPDD)/2 mm distance‐to‐agreement (DTA) and a threshold of 30% of the maximum dose. This criterion was determined based on previous studies,21, 22, 23 and the threshold was set according to the dose constraints of the critical organs.…”

Section: Methodsmentioning

confidence: 99%

Clinical usefulness of MLCs in robotic radiosurgery systems for prostate SBRT

Tomida

Kamomae

Suzuki

et al. 2017

J Applied Clin Med Phys

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Stereotactic body radiation therapy (SBRT) using recently introduced multileaf collimators (MLC) is preferred over circular collimators in the treatment of localized prostate cancer. The objective of this study was to assess the clinical usefulness of MLCs in prostate SBRT by comparing the effectiveness of treatment plans using fixed collimators, variable collimators, and MLCs and by ensuring delivery quality assurance (DQA) for each. For each patient who underwent conventional radiation therapy for localized prostate cancer, mock SBRT plans were created using a fixed collimator, a variable collimator, and an MLC. The total MUs, treatment times, and dose–volume histograms of the planning target volumes and organs at risk for each treatment plan were compared. For DQA, a phantom with a radiochromic film or an ionization chamber was irradiated in each plan. We performed gamma‐index analysis to evaluate the consistency between the measured and calculated doses. The MLC‐based plans had an ~27% lower average total MU than the plans involving other collimators. Moreover, the average estimated treatment time for the MLC plan was 31% and 20% shorter than that for the fixed and variable collimator plans respectively. The gamma‐index passing rate in the DQA using film measurements was slightly lower for the MLC than for the other collimators. The DQA results acquired using the ionization chamber showed that the discrepancies between the measured and calculated doses were within 3% in all cases. The results reinforce the usefulness of MLCs in robotic radiosurgery for prostrate SBRT treatment planning; most notably, the total MU and treatment time were both reduced compared to the cases using other types of collimators. Moreover, although the DQA results based on film dosimetry yielded a slightly lower gamma‐index passing rate for the MLC than for the other collimators, the MLC accuracy was determined to be sufficient for clinical use.

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“…[11][12][13] 2D film dosimetry offers superior spatial resolution for small field measurements, but the resulting dose distributions are sensi- The CyberKnife system has a predefined safety zone around the patient based on the patient's size. When we perform the patient-specific QA for a patient with the brain tumor, special attention is required to avoid the collision between the patient-specific QA phantom including Octavius 1000SRS detector and the moving robot arm due to the narrow patient safety zone.…”

Section: Discussionmentioning

confidence: 99%

Patient-Specific Quality Assurance in a Multileaf Collimator-Based CyberKnife System Using the Planar Ion Chamber Array

et al. 2018

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This paper describes the clinical use of the dose verification of multileaf collimator (MLC)-based CyberKnife plans by combining the Octavius 1000SRS detector and water-equivalent RW3 slab phantom. The slab phantom consists of 14 plates, each with a thickness of 10 mm. One plate was modified to support tracking by inserting 14 custom-made fiducials on surface holes positioned at the outer region of 10×10 cm 2 . The fiducial-inserted plate was placed on the 1000SRS detector and three plates were additionally stacked up to build the reference depth. Below the detector, 10 plates were placed to avoid longer delivery times caused by proximity detection program alerts. The cross-calibration factor prior to phantom delivery was obtained by performing with 200 monitor units (MU) on the field size of 95×92.5 mm 2 . After irradiation, the measured dose distribution of the coronal plane was compared with the dose distribution calculated by the MultiPlan treatment planning system. The results were assessed by comparing the absolute dose at the center point of 1000SRS and the 3-D Gamma (g) index using 220 patient-specific quality assurance (QA). The discrepancy between measured and calculated doses at the center point of 1000SRS detector ranged from −3.9% to 8.2%. In the dosimetric comparison using 3-D g-function (3%/3 mm criteria), the mean passing rates with g-parameter ≤ 1 were 97.4%±2.4%. The combination of the 1000SRS detector and RW3 slab phantom can be utilized for dosimetry validation of patient-specific QA in the CyberKnife MLC system, which made it possible to measure absolute dose distributions regardless of tracking mode.

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Film-based delivery quality assurance for robotic radiosurgery: Commissioning and validation

Cited by 33 publications

References 27 publications

High resolution ion chamber array delivery quality assurance for robotic radiosurgery: Commissioning and validation

High resolution ion chamber array delivery quality assurance for robotic radiosurgery: Commissioning and validation

Clinical usefulness of MLCs in robotic radiosurgery systems for prostate SBRT

Patient-Specific Quality Assurance in a Multileaf Collimator-Based CyberKnife System Using the Planar Ion Chamber Array

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