The effect of MLC speed and acceleration on the plan delivery accuracy of VMAT

Park, Jong Min; Wu, Hong Gyun; Kim, Jin Ho; Carlson, Joel; Kim, K.

doi:10.1259/bjr.20140698

Cited by 48 publications

(58 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this work, we also tried to analyze MLC speed properties because it is an important VMAT plan parameter and it has direct relation to beam to the scale of beam modulation and deliverability [6,[14][15][16][17]28]. Thus, VMAT plans can be characterized by MLC speed.…”

Section: ) Mlc Speed Errormentioning

confidence: 99%

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

Rahman

Kim

2019

J Radiat Prot Res

View full text Add to dashboard Cite

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.

show abstract

Section: ) Mlc Speed Errormentioning

confidence: 99%

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

Rahman

Kim

2019

J Radiat Prot Res

View full text Add to dashboard Cite

show abstract

“…In radiation therapy, MV x-ray beams and the resulting 3-D dose distributions are defined with mm accuracy throughout the target volume (e.g., tumor) and intervening tissues. [9][10][11][12][13][14][15][16][17][18][19] Precision multileaf collimators control the lateral extent of the beam and allow shaped targeting. Combined with a rotating gantry and freedom of movement of the patient table, advanced inverse treatment planning algorithms allow the maximum uniform target dose with minimal dose to the intervening organs.…”

Section: Current Medical X-ray Technologiesmentioning

confidence: 99%

Optical and x-ray technology synergies enabling diagnostic and therapeutic applications in medicine

Pogue

Wilson

2018

J. Biomed. Opt.

View full text Add to dashboard Cite

X-ray and optical technologies are the two central pillars for human imaging and therapy. The strengths of x-rays are deep tissue penetration, effective cytotoxicity, and the ability to image with robust projection and computed-tomography methods. The major limitations of x-ray use are the lack of molecular specificity and the carcinogenic risk. In comparison, optical interactions with tissue are strongly scatter dominated, leading to limited tissue penetration, making imaging and therapy largely restricted to superficial or endoscopically directed tissues. However, optical photon energies are comparable with molecular energy levels, thereby providing the strength of intrinsic molecular specificity. Additionally, optical technologies are highly advanced and diversified, being ubiquitously used throughout medicine as the single largest technology sector. Both have dominant spatial localization value, achieved with optical surface scanning or x-ray internal visualization, where one often is used with the other. Therapeutic delivery can also be enhanced by their synergy, where radiooptical and optical-radio interactions can inform about dose or amplify the clinical therapeutic value. An emerging trend is the integration of nanoparticles to serve as molecular intermediates or energy transducers for imaging and therapy, requiring careful design for the interaction either by scintillation or Cherenkov light, and the nanoscale design is impacted by the choices of optical interaction mechanism. The enhancement of optical molecular sensing or sensitization of tissue using x-rays as the energy source is an important emerging field combining x-ray tissue penetration in radiation oncology with the molecular specificity and packaging of optical probes or molecular localization. The ways in which x-rays can enable optical procedures, or optics can enable x-ray procedures, provide a range of new opportunities in both diagnostic and therapeutic medicine. Taken together, these two technologies form the basis for the vast majority of diagnostics and therapeutics in use in clinical medicine.

show abstract

“…MLC positions, gantry rotation speeds, and dose-rates) increased the complexity of delivery methods and involve large uncer-tainties. 4) Therefore, patient-specific quality assurance (QA) should be performed prior to the first treatment fraction for a patient being treated with IMRT or VMAT. [5][6][7] In recent years, electronic portal imaging device (EPID) has been introduced for patient-specific dosimetry owing to the high resolution, temporal stability, negligible set-up time, and proven high accuracy.…”

Section: Introductionmentioning

confidence: 99%

Verification of Extended Source-To-Imager Distance (SID) Correction for Portal Dosimetry

et al. 2018

View full text Add to dashboard Cite

This study aimed to evaluate and verify a process for correcting the extended source-to-imager distance (SID) in portal dosimetry (PD). In this study, eight treatment plans (four volumetric modulated arc therapy and four intensity-modulated radiation therapy plans) at different treatment sites and beam energies were selected for measurement. A Varian PD system with portal dose image prediction (PDIP) was used for the measurement and verification. To verify the integrity of the plan, independent measurements were performed with the MapCHECK device. The predicted and measured fluence were evaluated using the gamma passing rate. The output ratio was defined as the ratio of the absolute dose of the reference SID (100 cm) to that of each SID (120 cm or 140 cm). The measured fluence for each SID was absolutely and relatively compared. The average SID output ratios were 0.687 and 0.518 for 120 SID and 140 SID, respectively; the ratio showed less than 1% agreement with the calculation obtained by using the inverse square law. The resolution of the acquired EPIDs were 0.336, 0.280, and 0.240 for 100, 120, and 140 SID, respectively. The gamma passing rates with PD and MapCHECK exceeded 98% for all treatment plans and SIDs. When autoalignment was performed in PD, the X-offset showed no change, and the Y-offset decreased with increasing SID. The PD-generated PDIP can be used for extended SID without additional correction.

show abstract

The effect of MLC speed and acceleration on the plan delivery accuracy of VMAT

Abstract: As the MLC speeds and accelerations increased, VMAT delivery accuracy reduced.

Cited by 48 publications

References 33 publications

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

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

Optical and x-ray technology synergies enabling diagnostic and therapeutic applications in medicine

Verification of Extended Source-To-Imager Distance (SID) Correction for Portal Dosimetry

Contact Info

Product

Resources

About