Set-up errors and planning target volume margins in head and neck cancer radiotherapy: a clinical study of image guidance with on-line cone-beam computed tomography

Dionisi, Francesco; Palazzi, Mauro; Bracco, Francesco; Brambilla, M.G.; Carbonini, C.; Asnaghi, D.; Monti, A.F.; Torresin, A.

doi:10.1007/s10147-012-0395-7

Cited by 27 publications

(19 citation statements)

References 25 publications

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“…In our study, CBCT effectively improved the accuracy of VMAT in NPC patients because the inter-fraction systematic error could be decreased from 1.0–1.4 mm to 0.4–0.5 mm, which was similar to the results reported by Wang et al and Dionisi et al [5,17]. While the uncertainties in delivering RT can be reduced with CBCT systems, it is important to understand the uncertainties arising from this process.…”

Section: Discussionsupporting

confidence: 91%

Evaluation of inter-fraction and intra-fraction errors during volumetric modulated arc therapy in nasopharyngeal carcinoma patients

et al. 2013

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BackgroundThis prospective study was conducted to evaluate inter- and intra-fraction errors in nasopharyngeal carcinoma (NPC) patients undergoing volumetric modulated arc therapy (VMAT) using cone-beam computed tomography (CBCT) and to thus obtain planning target volume (PTV) margins to effectively guide treatment in the future.MethodsFifteen NPC patients scheduled to undergo VMAT were prospectively enrolled in the study. For each patient, three CBCT scans were obtained; one after daily conventional positioning, one after online correction with 2 mm tolerance and one after 1 week of VMAT delivery. The scans were registered to the planning CT to determine the inter- and intra-fraction errors. Patient positioning errors were analyzed for time trends over the course of radiotherapy. PTV margins were calculated from the systematic (Σ) and random (σ) errors.ResultsThe average absolute values of the pre-correction, post-correction and intra-fraction errors (in order) were 1.1, 0.6 and 0.4 mm in the medial–lateral (ML) direction, 1.2, 0.7 and 0.5 mm in the superior–inferior (SI) direction and 1.1, 0.7 and 0.5 mm in the anterior–posterior (AP) direction. The corresponding Σ were 1.0–1.4 mm, 0.4–0.5 mm and 0.2–0.4 mm, while the corresponding σ were 0.7–0.8 mm, 0.6–0.7 mm and 0.5–0.6 mm. With time, gradual increases in both the inter- and intra-fraction three-dimensional displacements were observed (P = 0.019 and P = 0.044, respectively). The total PTV margins accounting for pre-correction and intra-fraction errors were 3.4–4.1 mm and those accounting for post-correction and intra-fraction errors were 1.7–2.2 mm.ConclusionsCBCT is an effective modality to evaluate and improve the accuracy of VMAT in NPC patients. Inter- and intra-fraction three-dimensional displacements increased as a function of time during the course of radiotherapy. In our institution, we recommend a PTV margin of 5 mm for NPC patients undergoing VMAT without CBCT and 3 mm for those treated with rigorous daily CBCT scans.

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Section: Discussionsupporting

confidence: 91%

Evaluation of inter-fraction and intra-fraction errors during volumetric modulated arc therapy in nasopharyngeal carcinoma patients

et al. 2013

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“…10 Population random (r) and systematic (Σ) errors were calculated as the mean of the individual random errors and the SD of the individual systematic errors respectively. For calculating set up error and resultant margins, 11 both Van Herk's (2.5Σ + 0.7r) and Stroom's (2Σ + 0.7r) margin calculations 12,13 were selected.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of accuracy and reproducibility of a relocatable maxillary fixation system for fractionated intracranial stereotactic radiation therapy

Russo

Owen

Bernard

et al. 2015

J of Medical Radiation Sci

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IntroductionAccurate localisation is an essential component for the delivery of intracranial stereotactic treatment. For fractionated stereotactic radiotherapy, we compared the daily localisation accuracy of a standard thermoplastic mask with a new maxillary fixation device (MFD).MethodsDaily pre‐treatment kV cone‐beam computed tomography (CBCT) scans of 23 patients (12 localised in the MFD and 11 in the mask) with benign skull‐based lesions were reviewed retrospectively. The set up accuracy was measured in 6° of freedom, to ascertain both individual and population random and systematic errors. The appropriate clinical target volume to planning target volume margin was computed from set up error data.ResultsA total of 682 CBCT scans were evaluated. Systematic (Σ) and random (σ) population errors were Σ = 0.8 mm, 0.2 mm and 0.2 mm and σ = 0.3 mm, 0.3 mm and 0.2 mm, respectively, for the standard mask in the left/right (LR), superior/inferior (SI), and anterior/posterior (AP) translational planes, and Σ = 0.2 mm, 0.1 mm and 0.2 mm and σ = 0.2 mm, 0.3 mm and 0.2 mm, respectively, for the MFD. There was a reduction in rotation errors in the MFD compared to the mask. Margin calculations suggested an isotropic margin could be safely reduced to 2 mm for the MFD.ConclusionThe two devices demonstrate similar daily positional accuracy for fractionated stereotactic treatment of intracranial lesions. Combined with daily image guidance and couch correction, either of these devices is a viable frameless option for fractionated stereotactic radiation therapy.

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“…Current systems available include orthogonal imaging with planar radiographs, ultrasonography, cone-beam CT scans, fiducial markers with planar radiographs or cone-beam CT scans, radiofrequency transponders, infrared cameras, video cameras, and gating mechanisms that automatically can stop or resume treatment based on correct positioning of the patient or body part such as the eye ( fig. 3) [21][22][23][24].…”

Section: Image-guided Radiation Therapymentioning

confidence: 99%

Teletherapy: Advanced Techniques

Stockham

Balagamwala

Singh

et al. 2013

Ophthalmic Radiation Therapy

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Radiotherapy has been utilized as a treatment for ophthalmologic processes for more than one hundred years. Over this century, the field of ophthalmologic oncology has been revolutionized through medical discoveries, development of novel surgical interventions, and innovation of advanced radiotherapy techniques. In this chapter, novel radiotherapy techniques are considered. Material presented will build on basic radiation therapy principles, techniques, and treatment parameters established in the previous chapter through consideration of intensity modulated radiotherapy, stereotactic radiotherapy, and heavy ion therapy. Deliberation of matters common across advanced radiotherapy techniques including target delineation, treatment planning, and requisites for ensuring accurate, precise treatment delivery will precede discussion of advanced radiotherapy techniques as applied to the management ophthalmologic malignancies.

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Set-up errors and planning target volume margins in head and neck cancer radiotherapy: a clinical study of image guidance with on-line cone-beam computed tomography

Cited by 27 publications

References 25 publications

Evaluation of inter-fraction and intra-fraction errors during volumetric modulated arc therapy in nasopharyngeal carcinoma patients

Evaluation of inter-fraction and intra-fraction errors during volumetric modulated arc therapy in nasopharyngeal carcinoma patients

Evaluation of accuracy and reproducibility of a relocatable maxillary fixation system for fractionated intracranial stereotactic radiation therapy

Teletherapy: Advanced Techniques

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