The development and verification of a highly accurate collision prediction model for automated noncoplanar plan delivery

Yu, Victoria; Tran, A.; Nguyen, Dan; Cao, Minsong; Ruan, Dan; Low, Daniel A.; Sheng, Ke

doi:10.1118/1.4932631

Cited by 59 publications

(80 citation statements)

References 31 publications

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“…The delivery time of 4π plans involving a large number of beams can be excessively long in the manual mode. This limitation will be overcome using automating non-coplanar plan delivery [19]. …”

Section: Discussionmentioning

confidence: 99%

“…4π optimization begins with a candidate pool of 1162 non-coplanar beams, each 6° apart in the 4π solid angle space. Using a computer assisted design (CAD) model of the Varian TrueBeam machine and a 3D human surface model, each angle is simulated and subsequently eliminated if a collision is predicted between the gantry and the couch or patient [19]. The remaining beams were divided into 5 × 5 mm 2 beamlets, whose dose was calculated using convolution/superposition and Monte Carlo calculated 6MV polyenergetic kernels as described previously [20, 21].…”

Section: Methodsmentioning

confidence: 99%

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Treatment planning comparison of IMPT, VMAT and 4π radiotherapy for prostate cases

et al. 2017

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BackgroundIntensity-modulated proton therapy (IMPT), non-coplanar 4π intensity-modulated radiation therapy (IMRT), and volumetric-modulated arc therapy (VMAT) represent the most advanced treatment methods based on heavy ion and X-rays, respectively. Here we compare their performance for prostate cancer treatment.MethodsTen prostate patients were planned using IMPT with robustness optimization, VMAT, and 4π to an initial dose of 54 Gy to a clinical target volume (CTV) that encompassed the prostate and seminal vesicles, then a boost prescription dose of 25.2 Gy to the prostate for a total dose of 79.2 Gy. The IMPT plans utilized two coplanar, oblique scanning beams 10° posterior of the lateral beam positions. Range uncertainties were taken into consideration in the IMPT plans. VMAT plans used two full, coplanar arcs to ensure sufficient PTV coverage. 4π plans were created by inversely selecting and optimizing 30 beams from 1162 candidate non-coplanar beams using a greedy column generation algorithm. CTV doses, bladder and rectum dose volumes (V40, V45, V60, V65, V70, V75, and V80), R100, R50, R10, and CTV homogeneity index (D95/D5) were evaluated.ResultsCompared to IMPT, 4π resulted in lower anterior rectal wall mean dose as well as lower rectum V40, V45, V60, V65, V70, and V75. Due to the opposing beam arrangement, IMPT resulted in significantly (p < 0.05) greater femoral head doses. However, IMPT plans had significantly lower bladder, rectum, and anterior rectal wall max dose. IMPT doses were also significantly more homogeneous than 4π and VMAT doses.ConclusionCompared to the VMAT and 4π plans, IMPT treatment plans are superior in CTV homogeneity and maximum point organ-at-risk (OAR) doses with the exception of femur heads. IMPT is inferior in rectum and bladder volumes receiving intermediate to high doses, particularly to the 4π plans, but significantly reduced low dose spillage and integral dose, which are correlated to secondary cancer for patients with expected long survival. The dosimetric benefits of 4π plans over VMAT are consistent with the previous publication.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Treatment planning comparison of IMPT, VMAT and 4π radiotherapy for prostate cases

et al. 2017

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“…Collision of the machine with the patient during treatment, however, is still unsolved for these non‐isocentric, and non‐coplanar treatments. Most studies focus on collision prediction of the treatment plan, but not real‐time monitoring . Since the camera is on the couch, with the combination of the 3D computer‐aided design of the linac, it is feasible to build a real‐time collision avoidance system — if we know the location of patient relative to the machine, the collision can be avoided during the treatment.…”

Section: Discussionmentioning

confidence: 99%

Patient motion tracking for non‐isocentric and non‐coplanar treatments via fixed frame‐of‐reference 3D camera

Gasparyan¹,

Ko²,

Skinner³

et al. 2020

J Applied Clin Med Phys

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Purpose As C‐arm linac radiation therapy evolves toward faster, more efficient delivery, and more conformal dosimetry, treatments with increasingly complex couch motions are emerging. Monitoring the patient motion independently of the couch motion during non‐coplanar, non‐isocentric, or dynamic couch treatments is a key bottleneck to their clinical implementation. The goal of this study is to develop a prototype real‐time monitoring system for unconventional beam trajectories to ensure a safe and accurate treatment delivery. Methods An in‐house algorithm was developed for tracking using a couch‐mounted three‐dimensional (3D) depth camera. The accuracy of patient motion detection on the couch was tested on a 3D printed phantom created from the body surface contour exported from the treatment planning system. The technique was evaluated against a commercial optical surface monitoring system with known phantom displacements of 3, 5, and 7 mm in lateral, longitudinal, and vertical directions by placing a head phantom on a dynamic platform on the treatment couch. The stability of the monitoring system was evaluated during dynamic couch trajectories, at speeds between 10.6 and 65 cm/min. Results The proposed monitoring system agreed with the ceiling mounted optical surface monitoring system in longitudinal, lateral, and vertical directions within 0.5 mm. The uncertainty caused by couch vibration increased with couch speed but remained sub‐millimeter for speeds up to 32 cm/min. For couch speeds of 10.6, 32.2, and 65 cm/min, the uncertainty ranges were 0.27– 0.73 mm, 0.15–0.87 mm, and 0.28–1.29 mm, respectively. Conclusion By mounting a 3D camera in the same frame‐of‐reference as the patient and eliminating dead spots, this proof of concept demonstrates real‐time patient monitoring during couch motion. For treatments with non‐coplanar beams, multiple isocenters, or dynamic couch motion, this provides additional safety without additional radiation dose and avoids some of the complexity and limitations of room mounted systems.

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“…Moreover, they reported that the quadrature sum of the translational uncertainties (maximum value was 1.09 mm at couch angle of 270° using a weight of 70 kg) mostly depended on couch angles rather than weights of the phantom. Noncoplanar beams (or arcs) are commonly used in SRS/SRT treatment with a linear accelerator to improve dose conformity and normal tissue sparing . Murphy et al analyzed the patterns of patient movements during frameless image‐guided radiosurgery with the CyberKnife.…”

Section: Introductionmentioning

confidence: 99%

Impact of patient positioning uncertainty in noncoplanar intracranial stereotactic radiotherapy

Tanaka

Oita

Inomata

et al. 2020

J Applied Clin Med Phys

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The aim of this study is to evaluate the patient positioning uncertainty in noncoplanar stereotactic radiosurgery or stereotactic radiotherapy (SRS/SRT) for intracranial lesions with the frameless 6D ExacTrac system. In all, 28 patients treated with SRS/SRT of 70 treatment plans at our institution were evaluated in this study. Two X‐ray images with the frameless 6D ExacTrac system were first acquired to correct (XC) and verify (XV) the patient position at a couch angle of 0º. Subsequently, the XC and XV images were also acquired at each planned couch angle for using noncoplanar beams to detect position errors caused by rotating a couch. The translational XC and XV shift values at each couch angle were calculated for each plan. The percentages of the translational XC shift values within 1.0 mm for each planned couch angle for using noncoplanar beams were 77.86%, 72.26%, and 98.47% for the lateral, longitudinal, and vertical directions, respectively. Those within 2.0 mm were 98.22%, 97.96%, and 99.75% for the lateral, longitudinal, and vertical directions, respectively. The maximum absolute values of the translational XC shifts among all planned couch angles for using noncoplanar beams were 2.69, 2.45, and 2.17 mm for the lateral, longitudinal, and vertical directions, respectively. The overall absolute values of the translational XV shifts were less than 1.0 mm for all directions except for one case in the longitudinal direction. The patient position errors were detected after couch rotation for using noncoplanar beams, and they exceeded a planning target volume (PTV) margin of 1.0–2.0 mm used commonly in SRS/SRT treatment. These errors need to be corrected at each planned couch angle, or the PTV margin should be enlarged.

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The development and verification of a highly accurate collision prediction model for automated noncoplanar plan delivery

Cited by 59 publications

References 31 publications

Treatment planning comparison of IMPT, VMAT and 4π radiotherapy for prostate cases

Treatment planning comparison of IMPT, VMAT and 4π radiotherapy for prostate cases

Patient motion tracking for non‐isocentric and non‐coplanar treatments via fixed frame‐of‐reference 3D camera

Impact of patient positioning uncertainty in noncoplanar intracranial stereotactic radiotherapy

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