Dose verification in clinical imrt prostate incidents

Sandilos, P.; Angelopoulos, A.; Baras, Panagiotis; Dardoufas, K.; Karaiskos, P.; Kipouros, P.; Kozicki, Marek; Rosiak, Janusz M.; Sakelliou, L.; Seimenis, Ioannis; Vlahos, L.

doi:10.1016/j.ijrobp.2004.04.029

Cited by 62 publications

(49 citation statements)

References 36 publications

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“…The accuracy of the dose distributions calculated by the AAA in terms of their agreement with in-phantom verification measurements as typically performed prior to IMRT treatments [19,20] was assessed.…”

Section: Verificationmentioning

confidence: 99%

Clinical implications of the anisotropic analytical algorithm for IMRT treatment planning and verification

Bragg

Wingate

Conway

2008

Radiotherapy and Oncology

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Published paper AbstractPurpose: To determine the implications of the use of the Anisotropic Analytical Algorithm (AAA) for the production and dosimetric verification of IMRT plans for treatments of the prostate, parotid, nasopharynx and lung. Methods: 72 IMRT treatment plans produced using the Pencil Beam Convolution (PBC) algorithm were recalculated using the AAA and the dose distributions compared. 24 of the plans were delivered to inhomogeneous phantoms and verification measurements made using a pinpoint ionisation chamber. The agreement between the AAA and measurement was determined.Results: Small differences were seen in the prostate plans, with the AAA predicting slightly lower minimum PTV doses. In the parotid plans, there were small increases in the lens and contralateral parotid doses while the nasopharyngeal plans revealed a reduction in the volume of the PTV covered by the 95% isodose (the V 95% ) when the AAA was used. Large changes were seen in the lung plans, the AAA predicting reductions in the minimum PTV dose and large reductions in the V 95% . The AAA also predicted small increases in the mean dose to the normal lung and the V 20 . In the verification measurements, all AAA calculations were within 3% or 3.5mm distance to agreement of the measured doses. Conclusions:The AAA should be used in preference to the PBC algorithm for treatments involving low density tissue but this may necessitate re-evaluation of plan acceptability criteria. Improvements to the Multi-Resolution Dose Calculation algorithm used in the inverse planning are required to reduce the convergence error in the presence of lung tissue. There was excellent agreement between the AAA and verification measurements for all sites.3

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Section: Verificationmentioning

confidence: 99%

Clinical implications of the anisotropic analytical algorithm for IMRT treatment planning and verification

Bragg

Wingate

Conway

2008

Radiotherapy and Oncology

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“…Both gel formulations exhibit comparable dose sensitivity and a wide linear dose‐response region extending up to about 40 Gy. ( 6 , 13 ) The VIPAR gel also features an increased dynamic dose range of dose response (up to about 250 Gy) at the expense, however, of dose resolution in the low‐dose region (13) …”

Section: Methodsmentioning

confidence: 99%

“…This method simulates the entire patient treatment and presents the unique advantage of providing 3D dose distribution measurements with high resolution ( 3 – 6 ) in a water‐equivalent material, (7) thus allowing for the experimental verification of the 3D steep dose gradients met in gamma‐knife applications of single‐ or multishot applications to a single target. ( 8 – 11 ) Two different polymer gel dosimeter formulations (PABIG and VIPAR) were used.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and dose delivery accuracy evaluation in radiosurgery using polymer gels

Sandilos

Tatsis

Vlachos

et al. 2006

J Applied Clin Med Phys

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The polymer gel–magnetic resonance imaging (MRI) dosimetry technique was used to evaluate the mechanical and dose delivery accuracy in Leksell gamma‐knife stereotactic radiosurgery for the treatment of multiple targets. Two different polymer gel dosimeter formulations reported in the literature were prepared in‐house. A plan for the treatment of four brain metastases (targets) was generated. It involved the delivery of four 8‐mm collimator shots using different prescription isodose lines and different prescription doses for each target, keeping the maximum dose constant for all targets. A sample of each gel formulation was irradiated using a custom‐made phantom with an experimental procedure capable of testing the increased nominal mechanical accuracy of stereotactic radiosurgery. The irradiated dosimeters were evaluated using a clinical 1.5 T MR imager. Result manipulation in 3D allowed for the determination of the mechanical accuracy in the delivery of each shot through the comparison of measured versus planned shot center coordinates. Dose delivery accuracy was also evaluated by comparison of maximum dose values measured at the center of each shot as well as dose distribution measurements, with corresponding treatment‐planning calculations. Polymer gel dosimetry was found capable of verifying the complete chain of radiosurgery treatment in gamma‐knife applications involving the irradiation of multiple targets.PACS numbers: 87.53.Dq, 87.53.Ly, 87.53.Xd

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“…[5][6][7] However, IMRT does not allow the reduction of treatment margins that are used to account for geometric uncertainties. 8 In this context, image guided radiotherapy (IGRT), associated with IMRT, enables a more exact location of the target volume, 8 allowing the margin reduction.…”

Section: Introductionmentioning

confidence: 99%