Évaluation par tomodensitométrie du repositionnement en radiothérapie stéréotaxique fractionnée cérébrale

Pasquier, Dominique; Dubus, F.; Castelain, B.; Delplanque, Maurice; Bernier, V.; Buchheit, I.; Kerr, Christine; Santoro, Ilka Lopes; Huchet, A.; Causse, N.; Lartigau, É.

doi:10.1016/j.canrad.2009.05.003

Cited by 7 publications

(4 citation statements)

References 23 publications

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“…The results of patient 1,2,4 and 5 suggest that typical movement in this small population studied is restricted to a 1 mm region for the duration of treatment. This is similar to data presented by others [ 2 - 4 , 6 ]. However, the results of patient 3 suggest that a subpopulation of patients may exhibit occasional movement even under well-controlled conditions.…”

Section: Resultssupporting

confidence: 93%

“…During the course of a treatment fraction, we measured movement up to 2.4 mm in the longitudinal direction and 1.8 mm in the vertical direction which returned closer to baseline on subsequent imaging. Others have also shown that thermoplastic systems will sometimes exceed 1 mm linear motion [ 6 ] and have cautioned on the use of these immobilization systems without continuous monitoring of patient position [ 8 ]. Our results are similar to a recent publication reporting that a subpopulation of cranial SRS patients in thermoplastics masks may move 2 mm to 3 mm [ 9 ].…”

Section: Discussionmentioning

confidence: 99%

“…A potential drawback to this technology is the risk for greater head movement than would be possible with an invasive frame. While some have argued that submillimeter SRS is not feasible with current technology [ 5 ] others have demonstrated that thermoplastic masks can maintain stability within 1 mm in any linear direction [ 2 - 4 , 6 ]. These studies typically rely on x-ray imaging of the patient at the start of the treatment session with a repeat imaging session at the end of the treatment fraction, or may rely on repeated phantom imaging where no motion would be expected [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

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The Continuous Assessment of Cranial Motion in Thermoplastic Masks During CyberKnife Radiosurgery for Trigeminal Neuralgia

Bichay

Mayville

2016

Cureus

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Stereotactic radiosurgery (SRS) treatment is characterized by high doses per fraction and extremely steep dose gradients. This requires a great degree of accurate localization to the appropriate treatment position, and continuous immobilization during the treatment session. In the case of Trigeminal Neuralgia (TGN) treatment this is especially true as the very small target volume makes positional accuracy critical. In this study we carried out a quantitative analysis of patient motion during the full treatment fraction within a radiosurgery immobilization mask system. Patient cranial movement was assessed by using the image guidance stereo x-ray cameras on a CyberKnife (CK) M6 robotic radiosurgery system (Accuray, Sunnyvale, CA). A total of five patients received treatments for either right or left TGN. The duration of treatment varied from 24-64 minutes. Orthogonal images were taken every 15 seconds during the treatment to assess patient movement. Approximately 60 stereo images were taken per patient and a total of 560 images were analyzed in this study. The mean absolute movement in each of longitudinal, lateral or vertical directions was approximately 0.3 mm for the duration of the treatment; however, on occasion much greater movement was observed during a fraction. The maximum displacement was in the longitudinal direction and reached 2.4 mm compared to the initial setup. Images taken at the end of the treatment session showed that the patients typically return to a position closer to the original setup position than the maximum excursion that occurred. This data suggests that although this mask system appears stable during much of the treatment session; for some patients there may be momentary patient movements that take place. Frequent imaging and correction can help mitigate the effect of this movement. It is important to understand the limitations of non-invasive mask systems when used for very high precision treatment.

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Section: Resultssupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Continuous Assessment of Cranial Motion in Thermoplastic Masks During CyberKnife Radiosurgery for Trigeminal Neuralgia

Bichay

Mayville

2016

Cureus

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“…Changes to facial geometry during the course of treatments due to weight loss can also be an issue with the fit of masks [8], and the mask fabrication process itself can be time-consuming, uncomfortable, claustrophobic and distressing for patients [10][11][12]. While some studies report a 1 mm accuracy using thermoplastic masks [5,[13][14][15], others argue that high accuracy comparable to invasive fixation is not possible [16].…”

Section: Introductionmentioning

confidence: 99%