A Region-of-Interest Analysis of Setup Uncertainties in Head and Neck Radiotherapy

Zhang, L.; Dong, Lei; Ang, K. Kian; Lo, Justin; Tung, S.; Mason, B.; Wong, Pei Fong; Ahamad, A.; William, Marina; Rosenthal, D.I.; Chambers, Mark S.; Garden, Adam S.

doi:10.1016/j.ijrobp.2005.07.154

Cited by 7 publications

(7 citation statements)

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“…22,23 The intra-and interobserver variability is well known in literature. 8,14,15,18,22,23 Similar results were obtained in the publication by Song et al 15 Song et al compared the delineation process for the prostate on KVCT and MVCT. The uncertainty in prostate contouring (prostate has the HU value near the "soft tissue" and "muscles" in this study) was higher on MVCT vs. KVCT.…”

Section: Discussionsupporting

confidence: 74%

“…The interobserver contouring uncertainties of organs with electron density similar to organs at risk in human body were measured using KVCT and MVCT. 18,19 Additionally, the subjective image quality for perception and delineation of structures was assessed. This paper provides an opportunity to explore differences of contouring structures with different densities in a water phantom.…”

Section: Discussionmentioning

confidence: 99%

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Influence of the type of imaging on the delineation process during the treatment planning

Jackowiak

Bąk

Kowalik

et al. 2015

Reports of Practical Oncology & Radiotherapy

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a b s t r a c tAim: The aim of this study was to compare the intra-and interobserver contouring variability for structures with density of organ at risk in two types of tomography: kilovoltage computed tomography (KVCT) versus megavoltage computed tomography (MVCT). The intraand interobserver differences were examined on both types of tomography for structures which simulate human tissue or organs. Materials and methods:Six structures with density of the liver, bone, trachea, lung, soft tissue and muscle were created and used. For the measurements, the special water phantom with all structures was designed. To evaluate interobserver variability, five observers delineated the structures in both types of computed tomography (CT).Results: Intraobserver variability was in the range of 1-14% and was the largest for the liver. (51.86 vs. 67.97), the volume on MVCT was smaller than KVCT. The statistically significant differences between observers were observed for structures with density of the liver, bone and soft tissue on KVCT and for the liver, lung and soft tissue on MVCT. For the structures with density of the trachea and muscles, there were no significant differences for both types of tomography.Conclusions: During the contouring process the interobserver and intraobserver contouring uncertainty was larger on MVCT, especially for structures with HU near 80, compared with KVCT.

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Section: Discussionsupporting

confidence: 74%

Section: Discussionmentioning

confidence: 99%

Influence of the type of imaging on the delineation process during the treatment planning

Jackowiak

Bąk

Kowalik

et al. 2015

Reports of Practical Oncology & Radiotherapy

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“…Over the course of radiation therapy (RT), head and neck cancer patients undergo weight loss, tumor response, and posture changes (1)(2)(3)(4). Rigid registration (RR), optimizing only translations and rotations, cannot account for these geometric uncertainties.…”

Section: Introductionmentioning

confidence: 99%

Deformable Image Registration for Adaptive Radiation Therapy of Head and Neck Cancer: Accuracy and Precision in the Presence of Tumor Changes

Mencarelli

Kranen

Hamming‐Vrieze

et al. 2014

International Journal of Radiation Oncology*Biology*Physics

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“…Patients receiving intensity modulated radiation therapy ͑IMRT͒ for tumors in the head-and-neck region are typically immobilized using patient-specific immobilization masks, 1-8 and planned using treatment margins as small as 3-5 mm. [9][10][11][12] Although immobilization is typically better than 3 -5 mm, 3, 13,14 we have observed clinically that it is difficult to maintain the position of the shoulders ͑i.e., supraclavicular region͒ within an acceptable range from day to day. 14 We have found that a subset of patients can experience setup uncertainties in the supraclavicular region of 1 cm or more.…”

Section: Introductionmentioning

confidence: 99%

“…Other researchers have also reported larger setup uncertainties for this region. 3, 13 Recently, using repeat in-room computed tomography ͑CT͒ imaging, O'Daniel et al from M.D. Anderson Cancer Center presented results at the 2006 AAPM Annual Conference showing that daily bone alignment of head-and-neck patients can help keep parotid doses closer to that in the original treatment plan and can maintain a consistent equivalent uniform dose to the target.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the precision of portal‐image‐guided head‐and‐neck localization: An intra‐ and interobserver study

2007

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There is increasing evidence that, for some patients, image-guided intensity-modulated radiation therapy (IMRT) for head-and-neck cancer patients may maintain target dose coverage and critical organ (e.g., parotids) dose closer to the planned doses than setup using lasers alone. We investigated inter- and intraobserver uncertainties in patient setup in head-and-neck cancer patients. Twenty-two sets of orthogonal digital portal images (from five patients) were selected from images used for daily localization of head-and-neck patients treated with IMRT. To evaluate interobserver variations, five radiation therapists compared the portal images with the plan digitally reconstructed radiographs and reported shifts for the isocenter (approximately C2) and for a supraclavicular reference point. One therapist repeated the procedure a month later to evaluate intraobserver variations. The procedure was then repeated with teams of two therapists. The frequencies for which agreement between the shift reported by the observer and the daily mean shift (average of all observers for a given image set) were less than 1.5 and 2.5 mm were calculated. Standard errors of measurement for the intra- and interobserver uncertainty (SEMintra and SEMinter) for the individual and teams were calculated. The data showed that there was very little difference between individual therapists and teams. At isocenter, 80%-90% of all reported shifts agreed with the daily average within 1.5 mm, showing consistency in the ways both individuals and teams interpret the images (SEMinter approximately 1 mm). This dropped to 65% for the supraclavicular point (SEMinter approximately 1.5 mm). Uncertainties increased for larger setup errors. In conclusion, image-guided patient positioning allows head-and-neck patients to be controlled within 3-4 mm. This is similar to the setup uncertainties found for most head-and-neck patients, but may provide some improvement for the subset of patients with larger setup uncertainties.

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A Region-of-Interest Analysis of Setup Uncertainties in Head and Neck Radiotherapy

Cited by 7 publications

References 0 publications

Influence of the type of imaging on the delineation process during the treatment planning

Influence of the type of imaging on the delineation process during the treatment planning

Deformable Image Registration for Adaptive Radiation Therapy of Head and Neck Cancer: Accuracy and Precision in the Presence of Tumor Changes

Evaluation of the precision of portal‐image‐guided head‐and‐neck localization: An intra‐ and interobserver study

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