Positional Reproducibility of Pancreatic Tumors Under End-Exhalation Breath-Hold Conditions Using a Visual Feedback Technique

Nakamura, Mitsuhiro; Shibuya, Kazuhiko; Shiinoki, Takehiro; Matsuo, Yukinori; Nakamura, Akira; Nakata, Manabu; Sawada, Akira; Hiraoka, Masahiro

doi:10.1016/j.ijrobp.2010.05.046

Cited by 49 publications

(60 citation statements)

References 39 publications

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“…That way, the differences in motion magnitude between 4DCT, used for margin determination, and daily treatment could be eliminated. A remaining margin of 5 mm is reported to be suffi cient to account for all position variations in EE breath-hold for pancreatic cancer patients [25].…”

Section: Discussionmentioning

confidence: 99%

Differences in respiratory-induced pancreatic tumor motion between 4D treatment planning CT and daily cone beam CT, measured using intratumoral fiducials

et al. 2014

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Background. In radiotherapy, the magnitude of respiratory-induced tumor motion is often measured using a single four-dimensional computed tomography (4DCT). This magnitude is required to determine the internal target volume. The aim of this study was to compare the magnitude of respiratory-induced motion of pancreatic tumors on a single 4DCT with the motion on daily cone beam CT (CBCT) scans during a 3 -5-week fractionated radiotherapy scheme. In addition, we investigated changes in the respiratory motion during the treatment course. Material and methods. The mean peak-to-peak motion (i.e. magnitude of motion) of pancreatic tumors was measured for 18 patients using intratumoral gold fi ducials visible on CBCT scans made prior to each treatment fraction (10 -27 CBCTs per patient; 401 CBCTs in total). For each patient, these magnitudes were compared to the magnitude measured on 4DCT. Possible time trends were investigated by applying linear fi ts to the tumor motion determined from daily CBCTs as a function of treatment day.Results. We found a signifi cant (p Յ 0.01) difference between motion magnitude on 4DCT and on CBCT in superiorinferior, anterior-posterior and left-right direction, in 13, 9 and 12 of 18 patients, respectively. In the anteriorposterior and left-right direction no fractions had a difference Ն 5 mm. In the superior-inferior direction the difference was Ն 5 mm for 17% of the 401 fractions. In this direction, a signifi cant (p Յ 0.05) time trend in tumor motion was observed in 4 of 18 patients, but all trends were small ( Ϫ 0.17 -0.10 mm/day) and did not explain the large differences in motion magnitude between 4DCT and CBCT. Conclusion. A single measurement of the respiratory-induced motion magnitude of pancreatic tumors using 4DCT is often not representative for the magnitude during daily treatment over a 3 -5-week radiotherapy scheme. For this patient group it may be benefi cial to introduce breath-hold to eliminate respiratory-induced tumor motion.

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Section: Discussionmentioning

confidence: 99%

Differences in respiratory-induced pancreatic tumor motion between 4D treatment planning CT and daily cone beam CT, measured using intratumoral fiducials

et al. 2014

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“…As techniques for managing respiratory‐induced tumor movement, breath‐holding, (2) respiratory‐gated radiotherapy, 3 , 4 , 5 and dynamic tumor tracking delivery techniques (6) are effective in reducing the IMs, resulting in a lower dose to the normal tissue and, consequently, a lower risk of complications. To use these techniques in clinical practice, a correlation between external markers or sensors and internal tumor motion is needed.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a combined respiratory‐gating system comprising the TrueBeam linear accelerator and a new real‐time tumor‐tracking radiotherapy system: a preliminary study

Shiinoki

Kawamura

Uehara

et al. 2016

J Applied Clin Med Phys

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A combined system comprising the TrueBeam linear accelerator and a new real‐time, tumor‐tracking radiotherapy system, SyncTraX, was installed in our institution. The goals of this study were to assess the capability of SyncTraX in measuring the position of a fiducial marker using color fluoroscopic images, and to evaluate the dosimetric and geometric accuracy of respiratory‐gated radiotherapy using this combined system for the simple geometry. For the fundamental evaluation of respiratory‐gated radiotherapy using SyncTraX, the following were performed: 1) determination of dosimetric and positional characteristics of sinusoidal patterns using a motor‐driven base for several gating windows; 2) measurement of time delay using an oscilloscope; 3) positional verification of sinusoidal patterns and the pattern in the case of a lung cancer patient; 4) measurement of the half‐value layer (HVL in mm AL), effective kVp, and air kerma, using a solid‐state detector for each fluoroscopic condition, to determine the patient dose. The dose profile in a moving phantom with gated radiotherapy having a gating window ≤4 mm was in good agreement with that under static conditions for each photon beam. The total time delay between TrueBeam and SyncTraX was <227 ms for each photon beam. The mean of the positional tracking error was <0.4 mm for sinusoidal patterns and for the pattern in the case of a lung cancer patient. The air‐kerma rates from one fluoroscopy direction were 1.93±0.01, 2.86±0.01, 3.92±0.04, 5.28±0.03, and 6.60±0.05 mGy/min for 70, 80, 90, 100, and 110 kV X‐ray beams at 80 mA, respectively. The combined system comprising TrueBeam and SyncTraX could track the motion of the fiducial marker and control radiation delivery with reasonable accuracy; therefore, this system provides significant dosimetric improvement. However, patient exposure dose from fluoroscopy was not clinically negligible.PACS number(s): 87.53.Bn, 87.55.km, 87.55.Qr

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“…Our previous study showed that visual feedback provided high intra‐BH reproducibility of the pancreatic tumor (15) . Thus, some artifacts caused by low pancreatic tumor position reproducibility were not observed when matching the target on BH‐CBCT images.…”

Section: Discussionmentioning

confidence: 98%

“…A Real‐Time Position Management (RPM) system (Varian Medical Systems, Palo Alto, CA) illuminated and monitored anterior–posterior (AP) abdominal skin surface displacement. The abdominal motion signal gave visual feedback to the patient with the aid of video goggles (15) . The patients were asked to breathe following simple audio instructions, such as “breathe in, breathe out, and hold your breath”, while watching their abdominal displacement with the goggles.…”

Section: Methodsmentioning

confidence: 99%

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Interfraction positional variation in pancreatic tumors using daily breath‐hold cone‐beam computed tomography with visual feedback

Nakamura

Akimoto

Ono

et al. 2015

J Applied Clin Med Phys

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We assessed interfraction positional variation in pancreatic tumors using daily breath‐hold cone‐beam computed tomography at end‐exhalation (EE) with visual feedback (BH‐CBCT). Eleven consecutive patients with pancreatic cancer who underwent BH intensity‐modulated radiation therapy with visual feedback were enrolled. All participating patients stopped oral intake, with the exception of drugs and water, for >3 hr before treatment planning and daily treatment. Each patient was fixed in the supine position on an individualized vacuum pillow. An isotropic margin of 5 mm was added to the clinical target volume to create the planning target volume (PTV). The prescription dose was 42 to 51 Gy in 15 fractions. After correcting initial setup errors based on bony anatomy, the first BH‐CBCT scans were performed before beam delivery in every fraction. BH‐CBCT acquisition was obtained in three or four times breath holds by interrupting the acquisition two or three times, depending on the patient's BH ability. The image acquisition time for a 360° gantry rotation was approximately 90 s, including the interruption time due to BH. The initial setup errors were corrected based on bony structure, and the residual errors in the target position were then recorded. The magnitude of the interruptions variation in target position was assessed for 165 fractions. The systematic and random errors were 1.2 and 1.8 mm, 1.1 and 1.8 mm, and 1.7 and 2.9 mm in the left–right (LR), anterior–posterior (AP), and superior–inferior (SI) directions, respectively. Absolute interfraction variations of >5 mm were observed in 18 fractions (11.0%) from seven patients because of EE‐BH failure. In conclusion, target matching is required to correct interfraction variation even with visual feedback, especially to ensure safe delivery of escalated doses to patients with pancreatic cancer.PACS number: 87.57.Q‐, 87.57.‐s, 87.55.Qr

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Positional Reproducibility of Pancreatic Tumors Under End-Exhalation Breath-Hold Conditions Using a Visual Feedback Technique

Cited by 49 publications

References 39 publications

Differences in respiratory-induced pancreatic tumor motion between 4D treatment planning CT and daily cone beam CT, measured using intratumoral fiducials

Differences in respiratory-induced pancreatic tumor motion between 4D treatment planning CT and daily cone beam CT, measured using intratumoral fiducials

Evaluation of a combined respiratory‐gating system comprising the TrueBeam linear accelerator and a new real‐time tumor‐tracking radiotherapy system: a preliminary study

Interfraction positional variation in pancreatic tumors using daily breath‐hold cone‐beam computed tomography with visual feedback

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