The use of log file analysis within VMAT audits

McGarry, Conor K.; Agnew, Christina; Hussein, Mohammad; Tsang, Yatman; Hounsell, Alan R.; Clark, Catharine H.

doi:10.1259/bjr.20150489

Cited by 22 publications

(29 citation statements)

References 19 publications

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“…Figure 5 shows the daily distributions of the maxRMS by DFV for 5 different pcsr QA plans and 12 real treatment plans which were grouped into the corresponding plan class. Similar MLC position error was revealed by different other previous works [10][11][12][13].…”

Section: Mlc Movement Analysissupporting

confidence: 87%

Plan-Class Specific Reference Quality Assurance for Volumetric Modulated Arc Therapy

Rahman

Kim

2019

J Radiat Prot Res

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Background: There have been much efforts to develop the proper and realistic machine Quality Assurance (QA) reflecting on real Volumetric Modulated Arc Therapy (VMAT) plan. In this work we propose and test a special VMAT plan of plan-class specific (pcsr) QA, as a machine QA so that it might be a good solution to supplement weak point of present machine QA to make it more realistic for VMAT treatment. Materials and Methods: We divided human body into 5 treatment sites: brain, head and neck, chest, abdomen, and pelvis. One plan for each treatment site was selected from real VMAT cases and contours were mapped into the computational human phantom where the same plan as real VMAT plan was created and called plan-class specific reference (pcsr) QA plan. We delivered this pcsr QA plan on a daily basis over the full research period and tracked how much MLC movement and dosimetric error occurred in regular delivery. Several real patients under treatments were also tracked to test the usefulness of pcsr QA through comparisons between them. We used dynalog file viewer (DFV) and Dynalog file to analyze position and speed of individual MLC leaf. The gamma pass rate from portal dosimetry for different gamma criteria was analyzed to evaluate analyze dosimetric accuracy. Results and Discussion: The maxRMS of MLC position error for all plans were all within the tolerance limit of < 0.35 cm and the positional variation of maxPEs for both pcsr and real plans were observed very stable over the research session. Daily variations of maxRMS of MLC speed error and gamma pass rate for real VMAT plans were observed very comparable to those in their pcsr plans in good acceptable fluctuation. Conclusion: We believe that the newly proposed pcsr QA would be useful and helpful to predict the mid-term quality of real VMAT treatment delivery.

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Section: Mlc Movement Analysissupporting

confidence: 87%

Plan-Class Specific Reference Quality Assurance for Volumetric Modulated Arc Therapy

Rahman

Kim

2019

J Radiat Prot Res

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“…Magnitude of MLC errors (RMS <0.3 mm) and maximum gantry angle deviation (<0.2 degree) in this study for VMAT SBRT were 13,14 Minor differences between studies might be due to the differences of MLC positions, gantry angles, and differential dose indices with magnitudes of 1 mm, 1 degree, and 5 % respectively, while the passing rate of gamma analysis from ArcCheck TM measurement was still higher than 95 % tolerance that would be recognized as a pass…”

Section: Discussionmentioning

confidence: 51%

“…12 Several studies have been performed to evaluate the efficiency and effectiveness of machine log file analysis for volumetric-modulated arc therapy (VMAT). 13,14 Chan et al conducted a preliminary study on quantifying the deviations of monitor unit (MU) and gantry angles during delivery against the plan through log analysis for three head and neck and three prostate VMAT cases. 14 Mcgarry et al quantified the plan delivery accuracy in terms of log file-derived MLC positioning error with single center-specific plan and single standard plan for each participating center in VMAT audits.…”

Section: Introductionmentioning

confidence: 99%

“…14 Mcgarry et al quantified the plan delivery accuracy in terms of log file-derived MLC positioning error with single center-specific plan and single standard plan for each participating center in VMAT audits. 13 However, no comprehensive study with a large number of clinical cases has been conducted to evaluate simultaneously the deviations of MU, gantry angles, and MLC positions against the planned values using machine log files. The accuracy of all these beam parameters is essential to guarantee mechanical stability and dosimetrical accuracy.…”

Section: Introductionmentioning

confidence: 99%

“…Several studies have been performed to evaluate the efficiency and effectiveness of machine log file analysis for volumetric‐modulated arc therapy (VMAT) 13,14 . Chan et al conducted a preliminary study on quantifying the deviations of monitor unit (MU) and gantry angles during delivery against the plan through log analysis for three head and neck and three prostate VMAT cases 14 .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Patient‐specific quality assurance using machine log files analysis for stereotactic body radiation therapy (SBRT)

Chow

Kan

Chan

2020

J Applied Clin Med Phys

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An in-house trajectory log analysis program (LOGQA) was developed to evaluate the delivery accuracy of volumetric-modulated arc therapy (VMAT) for stereotactic body radiation therapy (SBRT). Methods have been established in LOGQA to provide analysis on dose indices, gantry angles, and multi-leaf collimator (MLC) positions. Between March 2019 and May 2020, 120 VMAT SBRT plans of various treatment sites using flattening filter-free (FFF) mode were evaluated using both LOGQA and phantom measurements. Gantry angles, dose indices, and MLC positions were extracted from log and compared with each plan. Integrated transient fluence map (ITFM) was reconstructed from log to examine the deviation of delivered fluence against the planned one. Average correlation coefficient of dose index versus gantry angle and ITFM for all patients were 1.0000, indicating that the delivered beam parameters were in good agreement with planned values. Maximum deviation of gantry angles and monitor units (MU) of all patients were less than 0.2 degree and 0.03 % respectively. Regarding MLC positions, maximum and rootmean-square (RMS) deviations from planned values were less than 0.6 mm and 0.3 mm respectively, indicating that MLC positions during delivery followed planned values in precise manner. Results of LOGQA were consistent with measurement, where all gamma-index passing rates were larger than 95 %, with 2 %/2 mm criteria. Three types of intentional errors were introduced to patient plan for software validation. LOGQA was found to recognize the introduced errors of MLC positions, gantry angles, and dose indices with magnitudes of 1 mm, 1 degree, and 5 %, respectively, which were masked in phantom measurement. LOGQA was demonstrated to have the potential to reduce or even replace patient-specific QA measurements for SBRT plan delivery provided that the frequency and amount of measurement-based machine-specific QA can be increased to ensure the log files record real values of machine parameters.

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Assessment of the Sun Nuclear ArcCHECK to detect errors in 6MV FFF VMAT delivery of brain SABR using ROC analysis

Tattenberg

Hyde

Milette

et al. 2021

J Applied Clin Med Phys

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Institutions use a range of different detector systems for patient-specific quality assurance (QA) measurements conducted to assure that the dose delivered by a patient's radiotherapy treatment plan matches the calculated dose distribution.However, the ability of different detectors to detect errors from different sources is often unreported. This study contains a systematic evaluation of Sun Nuclear's Arc-CHECK in terms of the detectability of potential machine-related treatment errors.The five investigated sources of error were multileaf collimator (MLC) leaf positions, gantry angle, collimator angle, jaw positions, and dose output. The study encompassed the clinical treatment plans of 29 brain cancer patients who received stereotactic ablative radiotherapy (SABR). Six error magnitudes were investigated per source of error. In addition, the Eclipse AAA beam model dosimetric leaf gap (DLG) parameter was varied with four error magnitudes. Error detectability was determined based on the area under the receiver operating characteristic (ROC) curve (AUC). Detectability of DLG errors was good or excellent (AUC >0.8) at an error magnitude of at least ±0.4 mm, while MLC leaf position and gantry angle errors reached good or excellent detectability at error magnitudes of at least 1.0 mm and 0.6°, respectively. Ideal thresholds, that is, gamma passing rates, to maximize sensitivity and specificity ranged from 79.1% to 98.7%. The detectability of collimator angle, jaw position, and dose output errors was poor for all investigated error magnitudes, with an AUC between 0.

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The use of log file analysis within VMAT audits

Cited by 22 publications

References 19 publications

Plan-Class Specific Reference Quality Assurance for Volumetric Modulated Arc Therapy

Plan-Class Specific Reference Quality Assurance for Volumetric Modulated Arc Therapy

Patient‐specific quality assurance using machine log files analysis for stereotactic body radiation therapy (SBRT)

Assessment of the Sun Nuclear ArcCHECK to detect errors in 6MV FFF VMAT delivery of brain SABR using ROC analysis

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