Generation of arbitrary intensity profiles by dynamic jaws or multileaf collimators

Spirou, Spiridon V.; Chui, Chen Shou

doi:10.1118/1.597345

Cited by 331 publications

(211 citation statements)

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“…Therefore our task was to commission the Helios module to extend the CadPlan capabilities to IMRT. Helios uses the optimization algorithm of Spirou and Chui 10 , 11 to produce “optimal” fluences for the different fields. The resolution of the optimum fluence is

0.25 cm \times leaf width

(standard within Helios).…”

Section: Methodsmentioning

confidence: 99%

IMRT clinical implementation: Prostate and pelvic node irradiation using Helios and a 120‐leaf multileaf collimator

Clark

Mubata

Meehan

et al. 2002

J Applied Clin Med Phys

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Dynamic intensity modulated radiation therapy (IMRT) to treat prostate and pelvic nodes using the Varian 120‐leaf Millennium multileaf collimator (MLC) has been implemented in our clinic. This paper describes the procedures that have been undertaken to achieve this, including some of the commissioning aspects of Helios, verification of the dynamic dose delivery, and quality assurance (QA) of the dose delivered to the patient. Commissioning of Helios included measurements of transmission through the 120‐leaf MLC, which were found to be 1.7% for 6 mV and 1.8% for 10 MV. The rounded leaf edge effect, known as the dosimetric separation, was also determined using two independent methods. Values of 1.05 and 1.65 mm were obtained for 6 and 10 MV beams. Five test patients were planned for prostate and pelvic node irradiation to 70 and 50 Gy, respectively. Dose and fluence verification were carried out on specially designed phantoms and dose points in the prostate were measured to be within 2.0% (mean 0.9%, s.d. 0.6%) of the calculated dose and in the nodes within 3.0% (mean 1.6%, s.d. 1.1%). Following the results of this commissioning and implementation study, we have started to treat men with a target volume including the prostate and pelvic nodes using Helios optimized dynamic IMRT delivery in a dose escalation protocol.PACS number(s): 87.53.–j, 87.90.+y

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0.25 cm \times leaf width

(standard within Helios).…”

Section: Methodsmentioning

confidence: 99%

IMRT clinical implementation: Prostate and pelvic node irradiation using Helios and a 120‐leaf multileaf collimator

Clark

Mubata

Meehan

et al. 2002

J Applied Clin Med Phys

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“…23 Treatments were delivered with 6 MV photons utilizing the sliding window IMRT method on Varian linear accelerators with dynamic multi-leaf collimator (600C, 2100C or 2100 EX Linacs with Mark I, Mark II or Millenium DMLC, depending on the patient and machine availability). 23 Beam directions were manually chosen by the planner to satisfy the clinical dosimetric objectives for the tumor and surrounding normal structures. The planners generally attempted to keep dose to the contralateral lung low, although formal dosimetric criteria were not applied to this structure.…”

Section: Methods/materialsmentioning

confidence: 99%

Intensity-modulated radiation therapy (IMRT) for inoperable non-small cell lung cancer: The Memorial Sloan-Kettering Cancer Center (MSKCC) experience

Sura

Gupta

Yorke

et al. 2008

Radiotherapy and Oncology

126

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“…After the inverse planning, the leaf motion required for the accelerator is generated for each IMRT plan by using the sliding-window technique. 14 The final dose distribution in each plan was normalized to 95% coverage of the PTV receiving the prescribed dose (50.4 Gy in 28 fractions). …”

Section: Methodsmentioning

confidence: 99%

Impact of different IMRT techniques to improve conformity and normal tissue sparing in upper esophageal cancer

Amin

Kelaney

Elshamndy

et al. 2014

Int J Cancer Ther Oncol

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Purpose: Intensity modulated radiotherapy (IMRT) for cervical esophageal cancer is challenging. Although IMRT techniques using inverse planning algorithms are facilitating the treatment planning process, the irradiation dose to the normal tissues can a critical issue. This study was performed to investigate the effect of beam numbers and their directions and local optimization (1) dose conformity and homogeneity to the planning target volume (PTV) and (2) dose to the organ at risks (OARs). Methods: Four upper esophageal cancer cases were randomly selected for this treatment planning study. Eight IMRT plans were for each case with the same dose-volume constraints but with different beam numbers and arrangements. Local optimization using regular structures drawn automatically around the PTV with margins from 0.5-1.5 cm was performed. IMRT plans were evaluated with respect to isodose distributions, dose-volume histograms (DVHs) parameters, homogeneity index (HI), and conformity index (CI). The statistical comparison between the types of plans was done using the One Way ANOVA test. Results: results showed that IMRT using three or five beams was not sufficient to obtain good dose optimization. The seven field plans showed the best coverage for the PTV with tolerable doses for the OARs, and the beam orientation was very critical. Increasing beams (Bs) number from 7 to 13 did not show significant differences in the PTV coverage, while the mean lung dose was increased. The PTV coverage were 95. 1, 95.1, 98.1, 97.3, 97.3, 97.3, 97.0, and 97.0% for 3Bs, 5Bs, 7Bs, 9Bs, 13Bs, 7Bs(30), 7Bs(60) (beam angles were changed from 0 o to 30 o and 60 o ), and 7Bs(R) (seven IMRT plans with ring), respectively. The mean heart dose did not exceed 0.36 Gy with p < 0.05. For lung doses, the best plan was the one with 9Bs which reduced lung volume doses V20Gy (%) and V30Gy (%), and reduced mean lung dose from 5.4 to 4.5 Gy with p < 0.05 for 7Bs(R) plans. IMRT improved the homogeneity indices (p > 0.05), yet conformity was better with 9Bs and 7Bs(R) IMRT plans with p < 0.05. Conclusion: Seven equispaced coplanar intensity-modulated beams with an addition of a ring structure can produce desirable dose distributions to the PTV. Moreover, dose-volume of exposed normal lung can be reduced with 9Bs and 7Bs(R) IMRT plans.

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Generation of arbitrary intensity profiles by dynamic jaws or multileaf collimators

Cited by 331 publications

References 0 publications

IMRT clinical implementation: Prostate and pelvic node irradiation using Helios and a 120‐leaf multileaf collimator

IMRT clinical implementation: Prostate and pelvic node irradiation using Helios and a 120‐leaf multileaf collimator

Intensity-modulated radiation therapy (IMRT) for inoperable non-small cell lung cancer: The Memorial Sloan-Kettering Cancer Center (MSKCC) experience

Impact of different IMRT techniques to improve conformity and normal tissue sparing in upper esophageal cancer

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