Comparison of monitor unit calculations performed with a 3D computerized planning system and independent “hand” calculations: Results of three years clinical experience

Chan, Jackson

doi:10.1120/1.1506379

Cited by 13 publications

(10 citation statements)

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“…5͒ and others 28 gave recommended criteria for the absolute accuracy of the dose calculation, the literature on the expected level of agreement between primary and verification calculations for modern image-based 3D planning systems is limited. [29][30][31][32][33][34] The action level guidelines given in Tables II and III are therefore based primarily on the collective experience and expectations of the task group members. A base action level of 2% was postulated for simple field geometries, consistent with the TG-53 criterion of 2% dose accuracy between calculations and measurements.…”

Section: Via Action Levels For Mu Disagreementmentioning

confidence: 99%

“…However, they did not include an off-axis factor for the supraclavicular fields nor did the spreadsheet calculation account for beam hardening due to the physical wedge for the rectal fields. Chan et al 30 compared manual calculations to homogeneous calculations from a 3D TPS with the aim of evaluating the usefulness of the manual calculation as a verification tool. They found average ratios of verification to TPS MUs for four sites ranged between 1.010 and 1.013, and standard deviations of 0.005-0.016, with the largest variations encountered for breast treatments and supraclavicular fields.…”

Section: Via Action Levels For Mu Disagreementmentioning

confidence: 99%

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Verification of monitor unit calculations for non‐IMRT clinical radiotherapy: Report of AAPM Task Group 114

et al. 2010

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The requirement of an independent verification of the monitor units ͑MU͒ or time calculated to deliver the prescribed dose to a patient has been a mainstay of radiation oncology quality assurance. The need for and value of such a verification was obvious when calculations were performed by hand using look-up tables, and the verification was achieved by a second person independently repeating the calculation. However, in a modern clinic using CT/MR/PET simulation, computerized 3D treatment planning, heterogeneity corrections, and complex calculation algorithms such as convolution/superposition and Monte Carlo, the purpose of and methodology for the MU verification have come into question. In addition, since the verification is often performed using a simpler geometrical model and calculation algorithm than the primary calculation, exact or almost exact agreement between the two can no longer be expected. Guidelines are needed to help the physicist set clinically reasonable action levels for agreement. This report addresses the following charges of the task group: ͑1͒ To re-evaluate the purpose and methods of the "independent second check" for monitor unit calculations for non-IMRT radiation treatment in light of the complexities of modernday treatment planning. ͑2͒ To present recommendations on how to perform verification of monitor unit calculations in a modern clinic. ͑3͒ To provide recommendations on establishing action levels for agreement between primary calculations and verification, and to provide guidance in addressing discrepancies outside the action levels. These recommendations are to be used as guidelines only and shall not be interpreted as requirements.

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Section: Via Action Levels For Mu Disagreementmentioning

confidence: 99%

Section: Via Action Levels For Mu Disagreementmentioning

confidence: 99%

Verification of monitor unit calculations for non‐IMRT clinical radiotherapy: Report of AAPM Task Group 114

et al. 2010

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“…The option to import the body contour for VMAT plans makes it possible to assign a source to surface distance (SSD) and depth of calculation to each control point (a VMAT field is composed of 177 or 178 control points), otherwise averaged values of SSD and depth must be assigned to all control points. In the previous studies 4,15,23 using PTW's Diamond software (version 5.01.02.131 or higher), the 8,24 In our present work, using Diamond SCS, version-6, the heterogeneity corrections were done by assigning relative electron density values to each organ. The structure sets are imported from TPS along with the RT plan into Diamond.…”

Section: Diamond Scs Calculations For Vmat Plans With Heterogeneity Cmentioning

confidence: 96%

Validation and clinical implementation of commercial secondary check software with heterogeneity corrections

Kuppusamy

Nagarajan

Murugan

2016

Reports of Practical Oncology & Radiotherapy

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“…MUs are directly related to the dose delivered to the patient. Specific task groups have recommended comparing the monitor unit calculation for different kinds of plans in order to confirm the validity of monitor unit calculations [3][4][5]. The aim of our study was to compare monitor units and dose distribution obtained with the two algorithms respectively: the Clarkson and the PBC algorithms, and to evaluate the possible change in the clinical outcome of treatment plans.…”

Section: Introductionmentioning

confidence: 99%

Clinical Comparison of Pencil Beam Convolution and Clarkson Algorithms for Dose Calculation

Chaikh¹,

Giraud²,

Balosso³

2013

JCT

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Purpose: The purpose of this work is to study and quantify the differences in calculated dose computed with two algorithms available in treatment planning systems: Pencil Beam Convolution and Clarkson. Material and Methods: Four different types of treatment cases were analyzed: lung, head and neck, brain and prostate. For each case, the volume definition was based on a clinical CT-scan acquisition. The patients were treated with 3-dimensional radiation therapy. For each patient, 2 treatment plans were generated using exactly the same configuration of beams. In plan 1 and plan 2, the dose was calculated using the Clarkson and Pencil Beam Convolution algorithms, respectively, without heterogeneity correction. To evaluate the treatment plans, the monitor units, isodose curves, dose volume histograms and quality index were compared. A statistical analysis was carried out using Wilcoxon signed rank test. Results: The difference observed for monitor unites was 1.2% for lung and less than 1% for head and neck, brain and prostate. Wilcoxon test showed that there was "no statically significant difference, (p > 0.05)". The dosimetric parameters derived from dose volume histograms were higher for organs at risks using Clarkson compared to Pencil Beam Convolution algorithm inviting clinician to make "safer" prescriptions. For quality index there was no statistically significant difference between both algorithms for all quality indexes, (p > 0.05). Conclusion: The clinical evaluation of a treatment plan should be made regarding the calculation algorithm which, in turn, is linked to the experience of the clinician.

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Comparison of monitor unit calculations performed with a 3D computerized planning system and independent “hand” calculations: Results of three years clinical experience

Cited by 13 publications

References 0 publications

Verification of monitor unit calculations for non‐IMRT clinical radiotherapy: Report of AAPM Task Group 114

Verification of monitor unit calculations for non‐IMRT clinical radiotherapy: Report of AAPM Task Group 114

Validation and clinical implementation of commercial secondary check software with heterogeneity corrections

Clinical Comparison of Pencil Beam Convolution and Clarkson Algorithms for Dose Calculation

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