Evaluation of Rotational Errors in Treatment Setup of Stereotactic Body Radiation Therapy of Liver Cancer

Cao, Minsong; Lasley, Foster D.; Das, Indra J.; DesRosiers, Colleen; Slessinger, Eric D.; Cárdenes, Higinia R.

doi:10.1016/j.ijrobp.2012.05.018

Cited by 16 publications

(25 citation statements)

References 23 publications

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“…One patient (3%) described being uncomfortable in the BodyFIX with wrap at the post‐treatment questionnaire, which could suggest this patient did not tolerate the abdominal pressure 7, 9. The devices that patients thought were the most secure and prevented movement tended to be the BodyFIX without wrap and BodyFIX with vacuum wrap which in conjunction with the literature, staff opinions and imaging results suggest that these are strong accurate immobilisation devices 3, 8, 23…”

Section: Discussionmentioning

confidence: 93%

A randomised comparison of three different immobilisation devices for thoracic and abdominal cancers

et al. 2016

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IntroductionPatient immobilisation is critically important for both highly conformal conventionally fractionated radiotherapy and for stereotactic body radiotherapy. Different immobilisation devices are available to maintain patient position for radiotherapy but the most suitable one remains unknown.MethodsForty‐five patients were randomly allocated to one of three immobilisation devices; the Q fix arm shuttle, BodyFIX without wrap or BodyFIX with wrap. Patients were imaged before and after treatment to ascertain intra‐fraction and inter‐fraction motion. Bony anatomy was used for matching to determine the positional accuracy of each device. Treatments were timed using a standard method. Patient comfort and staff satisfaction questionnaires were also issued to determine comfort, ease of use and preferences for each device.ResultsThe BodyFIX without wrap was the more accurate device; however, the differences between the devices were not statistically significant. The BodyFIX with wrap was found to take significantly longer to set up and set down compared to the arm shuttle and the BodyFIX without wrap (all P < 0.001). Patients (37%) marginally preferred the BodyFIX with wrap. Most (81%) staff preferred the BodyFIX without wrap.ConclusionImmobilisation using the BodyFIX without wrap was deemed to be suitable for clinical use. It was a clinically accurate device, the more efficient in terms of set up and set down time, the most preferred by staff and was accepted by patients.

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Section: Discussionmentioning

confidence: 93%

A randomised comparison of three different immobilisation devices for thoracic and abdominal cancers

et al. 2016

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“…Table rotation was not performed as we do not have the 6 degree of freedom table. However, based on our earlier study indicating that rotation can be achieved by coordinate translation was used . Couch shifts associated with the interfractional setup errors were analyzed to assess the accuracy of the initial CBCT setups of each immobilization system along the three axes and by means of a 3D vector (3D vector: the root sum of LR 2 , AP 2 , and CC 2 ).…”

Section: Methodsmentioning

confidence: 99%

Evaluation of initial setup errors of two immobilization devices for lung stereotactic body radiation therapy (SBRT)

Ueda¹,

Teshima²,

Cárdenes

et al. 2017

J Applied Clin Med Phys

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The aim of this study was to investigate the accuracy and efficacy of two commonly used commercial immobilization systems for stereotactic body radiation therapy (SBRT) in lung cancer. This retrospective study assessed the efficacy and setup accuracy of two immobilization systems: the Elekta Body Frame (EBF) and the Civco Body Pro‐Lok (CBP) in 80 patients evenly divided for each system. A cone beam CT (CBCT) was used before each treatment fraction for setup correction in both devices. Analyzed shifts were applied for setup correction and CBCT was repeated. If a large shift (>5 mm) occurred in any direction, an additional CBCT was employed for verification after localization. The efficacy of patient setup was analyzed for 105 sessions (48 with the EBF, 57 with the CBP). Result indicates that the CBCT was repeated at the 1st treatment session in 22.5% and 47.5% of the EBF and CBP cases, respectively. The systematic errors {left–right (LR), anterior–posterior (AP), cranio‐caudal (CC), and 3D vector shift: (LR 2 + AP 2 + CC 2)1/2 (mm)}, were {0.5 ± 3.7, 2.3 ± 2.5, 0.7 ± 3.5, 7.1 ± 3.1} mm and {0.4 ± 3.6, 0.7 ± 4.0, 0.0 ± 5.5, 9.2 ± 4.2} mm, and the random setup errors were {5.1, 3.0, 3.5, 3.9} mm and {4.6, 4.8, 5.4, 5.3} mm for the EBF and the CBP, respectively. The 3D vector shift was significantly larger for the CBP (P < 0.01). The setup time was slightly longer for the EBF (EBF: 15.1 min, CBP: 13.7 min), but the difference was not statistically significant. It is concluded that adequate accuracy in SBRT can be achieved with either system if image guidance is used. However, patient comfort could dictate the use of CBP system with slightly reduced accuracy.

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“…To our knowledge, few studies have quantified the dosimetric effects of target rotations for SBRT liver treatments. 142,155 As discussed in Section 2.3.2, Chan et al 142 rotated and translated the contours for the CTV and PTV based on the aggregate translational and rotational errors for ten phases of the respiratory cycle, each equally weighted in the final dose accumulation for CyberKnife liver treatments. They analyzed data for 24 liver patients and found a relatively small median dose reduction of 1.1% and 0.0% for PTV and CTV, respectively, when the aggregate rotations were of −0.26° ± 0.51°, 0.14° ± 0.71°, 0.65° ± 0.61° in roll, pitch, and yaw directions, respectively.…”

Section: Chapter 5 Dosimetric Assessmentsmentioning

confidence: 99%

“…They analyzed data for 24 liver patients and found a relatively small median dose reduction of 1.1% and 0.0% for PTV and CTV, respectively, when the aggregate rotations were of −0.26° ± 0.51°, 0.14° ± 0.71°, 0.65° ± 0.61° in roll, pitch, and yaw directions, respectively. Cao et al 155 estimated rotational setup errors by aligning to soft tissue using the liver as a surrogate organ in CBCT and planning CT images for 20 SBRT liver treatments using conventional gantry-based linac delivery. They found the systematic setup errors were -0.29° ± 0.62°, -0.06°± 0.68°, and -0.24° ± 0.61° for roll, pitch, and yaw, with random errors of 1.05°, 0.80°, and 0.61°, respectively.…”

Section: Chapter 5 Dosimetric Assessmentsmentioning

confidence: 99%

“…Some research groups assessed the deformations 151 and the resulting dosimetric effects [152][153][154] using either 4DCT or CBCT data. Cao et al 155 evaluated the systematic and random errors associated with rotational setup variations for SBRT liver treatments by manually matching CBCT images with the planning CT images and found that more than 14.7% of the patient population had more than 2° of rotational error in at least one rotational direction (roll/pitch/yaw). In one study examining CBCT data for 29 liver patients, Bertholet et al 156 found a large day-to-day variation of rotations * The results in this Chapter have been published in a peer-reviewed journal (up to 16.9° and 28.6° in roll and yaw, respectively), which may be important for liver treatments especially without abdominal compression as is typical for CyberKnife treatments.…”

Section: Uniform Ptv Margins Introductionmentioning

confidence: 99%

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Patient-Specific Planning Target Volume Margins for Liver Stereotactic Robotic Radiosurgery

Liu¹

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Purpose: To create analytical tools for a proposed clinical workflow, which implements patientspecific planning target volume (PTV) margins for liver radiation therapy treatments. Methods and Materials: Treatment log files are analyzed for liver treatments to assess tumour motion-tracking accuracy. A uniform PTV margin is estimated that considers motion-tracking errors and deformations, provided that the impact of uncorrected rotations is minimized. A supervised machine learning algorithm employing retrospective data, which emulates a dry-run session prior to treatment planning, is used to investigate if motion-tracking errors are less than 2 mm, and consequently, the standard PTV margins can be reduced by 2 mm. For a safer implementation in the clinic, we employ a warning system that quantifies the probability of a geographic miss if the PTV margin is reduced for every subsequent fraction. A dosimetric analytical tool is proposed to retrospectively assess the dose to a target against different types of delivery errors. The tool is validated by radiochromic film measurements for two very different types of treatments, liver and trigeminal neuralgia (a cranial nerve disorder). Case studies are conducted to access the suitability of a selected PTV margin based on the geometrical and dosimetric coverage of targets. The range of rotations that can be safely allowed for trigeminal neuralgia treatments is quantified since rotational corrections cannot be applied by the system for this specific disease site. Results: Isotropic 4 mm PTV margins are sufficient to account for tracking errors and deformations for 95% of patients. For patient-specific PTV margins, the accuracy of predicting if motion-tracking errors are less than 2 mm is 0.84 ± 0.06 using 5-fold cross-validation. Using the warning system, 11 out of 64 cases predicted to be treated with 2 mm reduced PTV margins might

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Evaluation of Rotational Errors in Treatment Setup of Stereotactic Body Radiation Therapy of Liver Cancer

Cited by 16 publications

References 23 publications

A randomised comparison of three different immobilisation devices for thoracic and abdominal cancers

A randomised comparison of three different immobilisation devices for thoracic and abdominal cancers

Evaluation of initial setup errors of two immobilization devices for lung stereotactic body radiation therapy (SBRT)

Patient-Specific Planning Target Volume Margins for Liver Stereotactic Robotic Radiosurgery

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