Pitch, roll, and yaw variations in patient positioning

Kaiser, Adeel; Schultheiss, Timothy E.; Wong, Jeffrey Y.C.; Smith, David; Han, Chunhui; Vora, Nayana; Pezner, Richard D.; Chen, Yi Jen; Radany, Eric H.

doi:10.1016/j.ijrobp.2006.05.055

Cited by 69 publications

(41 citation statements)

References 20 publications

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“…The scan length in the superior–inferior direction included the entire planning target volume (PTV) whenever possible. Then, the MVCT to kilovoltage CT (kVCT) image registration was performed by the TomoTherapy system software to determine translational and rotational (roll, pitch, and yaw) (9) corrections. Usually, image registration was based on bony or bony and soft tissue anatomy.…”

Section: Methodsmentioning

confidence: 99%

A retrospective tomotherapy image‐guidance study: analysis of more than 9,000 MVCT scans for ten different tumor sites

Sánchez-Rubio

Rodríguez-Romero

Castro

2014

J Applied Clin Med Phys

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The purpose of this study was to quantify the systematic and random errors for various disease sites when daily MVCT scans are acquired, and to analyze alternative off‐line verification protocols (OVP) with respect to the patient setup accuracy achieved. Alignment data from 389 patients (9,418 fractions) treated at ten different anatomic sites with daily image‐guidance (IG) on a helical tomotherapy unit were analyzed. Moreover, six OVP were retrospectively evaluated. For each OVP, the frequency of the residual setup errors and additional margins required were calculated for the treatment sessions without image guidance. The magnitude of the three‐dimensional vector displacement and its frequency were evaluated for all OVP. From daily IG, the main global systematic error was in the vertical direction (4.4–9.4 mm), and all rotations were negligible (less than 0.5°) for all anatomic sites. The lowest systematic and random errors were found for H&N and brain patients. All OVP were effective in reducing the mean systematic error to less than 1 mm and 0.2° in all directions and roll corrections for almost all treatment sites. The treatment margins needed to adapt the residual errors should be increased by 2–5 mm for brain and H&N, around 8 mm in the vertical direction for the other anatomic sites, and up to 19 mm in the longitudinal direction for abdomen patients. Almost 70% of the sessions presented a setup error of 3 mm for OVPs with an imaging frequency above 50%. Only for brain patients it would be feasible to apply an OVP because the residual setup error could be compensated for with a slight margin increase. However, daily imaging should be used for anatomic sites of difficult immobilization and/or large interfraction movement.PACS numbers: 87.55.‐x, 87.56.‐v

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Section: Methodsmentioning

confidence: 99%

A retrospective tomotherapy image‐guidance study: analysis of more than 9,000 MVCT scans for ten different tumor sites

Sánchez-Rubio

Rodríguez-Romero

Castro

2014

J Applied Clin Med Phys

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“…Not all standard treatment tables allow rotational corrections; therefore, strategies for six‐degrees‐of‐freedom (DOF) corrections have been discussed and included the use of a combination of collimator, gantry, and/or the implementation of a robotic couch 19 , 20 , 21 , 22 , 23 . Soete et al (21) have proven that this 6 DOF patient setup correction improves the patient setup accuracy, and other authors reported experiences about the relevance of rotational shift when patients received high precision radiotherapy 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 …”

Section: Introductionmentioning

confidence: 99%

Adaptive optimization by 6 DOF robotic couch in prostate volumetric IMRT treatment: rototranslational shift and dosimetric consequences

Chiesa

Placidi

Azario

et al. 2015

J Applied Clin Med Phys

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The purpose of this study was to investigate the magnitude and dosimetric relevance of translational and rotational shifts on IGRT prostate volumetric‐modulated arc therapy (VMAT) using Protura six degrees of freedom (DOF) Robotic Patient Positioning System. Patients with cT3aN0M0 prostate cancer, treated with VMAT simultaneous integrated boost (VMAT‐SIB), were enrolled. PTV2 was obtained adding 0.7 cm margin to seminal vesicles base (CTV2), while PTV1 adding to prostate (CTV1) 0.7 cm margin in all directions, except 1.2 cm, as caudal margin. A daily CBCT was acquired before dose delivery. The translational and rotational displacements were corrected through Protura Robotic Couch, collected and applied to the simulation CT to obtain a translated CT (tCT) and a rototranslated CT (rtCT) on which we recalculated the initial treatment plan (TP). We analyzed the correlation between dosimetric coverage, organs at risk (OAR) sparing, and translational or rotational displacements. The dosimetric impact of a rototranslational correction was calculated. From October 2012 to September 2013, a total of 263 CBCT scans from 12 patients were collected. Translational shifts were <5mm in 81% of patients and the rotational shifts were <2∘ in 93% of patient scans. The dosimetric analysis was performed on 172 CBCT scans and calculating 344 VMAT‐TP. Two significant linear correlations were observed between yaw and the V20 femoral heads and between pitch rotation and V50 rectum (p<0.001); rototranslational correction seems to impact more on PTV2 than on PTV1, especially when margins are reduced. Rotational errors are of dosimetric significance in sparing OAR and in target coverage. This is relevant for femoral heads and rectum because of major distance from isocenter, and for seminal vesicles because of irregular shape. No correlation was observed between translational and rotational errors. A study considering the intrafractional error and the deformable registration is ongoing.PACS number: 87.55.de

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“…L'optimisation de la mise en place est quotidienne grâce à l'imagerie embarquée, en respectant un seuil de repositionnement jusqu'à 5 mm [33]. Cette technique augmente le temps de traitement par rapport à la RCMI mais optimise la protection des organes à risque (OAR).…”

Section: ❙ La Tomothérapie Hélicoïdaleunclassified

Radiothérapie des cancers du canal anal

Rochefordière¹,

Labib²,

Dauphinot³

et al. 2011

Cancérodig.

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❚ RésuméLa radio(chimio)thérapie correspond au traitement de référence des carcinomes épidermoïdes du canal anal localisés qui repré-sentent la majorité des cas. Elle a pour objectif d'obtenir une stéri-lisation tumorale définitive tout en conservant un sphincter anal fonctionnel. Cet article a pour objectif de préciser les indications et les modalités de la radiothérapie pelvienne dans cette situation. Il sera également question des nouvelles modalités d'irradiation (Radiothérapie Conformationnelle avec Modulation d'Intensité ; Tomothérapie hélicoïdale et irradiation avec modulation d'intensité volumétrique par Arc thérapie) qui permettent à la fois une meilleure définition des volumes cibles et une meilleure protection des organes à risque (intestin grêle, recto-sigmoïde, vessie, organes génitaux notamment). Cette dernière réduit la toxicité induite, ce qui permet d'envisager une réduction de la durée totale du traitement (réduction de la durée de la pause thérapeu-tique entre les 2 séquences de radiothérapie, voire suppression de cette pause avec traitement continu). La réduction de la toxicité devrait également permettre d'augmenter la dose totale déli-vrée dans le volume cible. L'intérêt d'une telle stratégie mérite d'être évalué. Mots-clésCanal anal, Radiothérapie, Modulation d'intensité, RCMI, Tomothérapie, Arc thérapie ❚ Abstract Radio(chemo)therapy is the standard treatment of localized epidermoid carcinomas of the anal canal, which represent the majority of cases. The aim of treatment is to obtain tumor sterilization while preserving functional anal sphincter. This article concerns the indications and the modalities of radiotherapy in this situation, with special attention to the new available radiation techniques (conformational static field intensity modulated radiotherapy; helicoidal tomotherapy; volumetric modulated arc therapy). These developments mainly allow to reduce the dose to normal tissues and organs at risk thereby minimizing the risk of toxicity. The reduction of the induced morbidity should allow to shorten the classical 2 to 6 weeks gap period between the two sequences of radiotherapy and therefore the total duration of treatment. It also should allow dose escalation to the tumor volume potentially leading to improved locoregional control.

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Pitch, roll, and yaw variations in patient positioning

Cited by 69 publications

References 20 publications

A retrospective tomotherapy image‐guidance study: analysis of more than 9,000 MVCT scans for ten different tumor sites

A retrospective tomotherapy image‐guidance study: analysis of more than 9,000 MVCT scans for ten different tumor sites

Adaptive optimization by 6 DOF robotic couch in prostate volumetric IMRT treatment: rototranslational shift and dosimetric consequences

Radiothérapie des cancers du canal anal

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