Interfractional Reproducibility in Pancreatic Position Based on Four-Dimensional Computed Tomography

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

doi:10.1016/j.ijrobp.2010.10.020

Cited by 17 publications

(8 citation statements)

References 33 publications

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“…Our results are consistent with those in the literature: the pancreas moves with breathing, especially in the SI and AP directions (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). Reported amplitudes of excursion vary depending on the mode of imaging or the use of voice coaching.…”

Section: Discussionsupporting

confidence: 91%

“…In the literature, in the SI direction, the pancreatic excursion varies from 0.5 cm to 2.4 cm ( Table 4). In our study, pancreatic motion seems to be larger than in previous studies using 4D-CT (13)(14)(15)(16)18). This could be explained by the audio coaching, which we have observed often induces deeper breathing but may improve the regularity of breathing amplitude (20)(21)(22).…”

Section: Discussioncontrasting

confidence: 59%

See 1 more Smart Citation

Modeling Pancreatic Tumor Motion Using 4-Dimensional Computed Tomography and Surrogate Markers

Huguet

Yorke

Davidson

et al. 2015

International Journal of Radiation Oncology*Biology*Physics

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Section: Discussionsupporting

confidence: 91%

Section: Discussioncontrasting

confidence: 59%

Modeling Pancreatic Tumor Motion Using 4-Dimensional Computed Tomography and Surrogate Markers

Huguet

Yorke

Davidson

et al. 2015

International Journal of Radiation Oncology*Biology*Physics

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“…Without using implanted fiducial markers, Shiinoki et al [22] studied inter- and intra- fractional tumor motion of 15 pancreatic cancer patients using sequential 4DCT during the treatment course. They observed intra- and inter-fractional motion similar to the results obtained here.…”

Section: Discussionmentioning

confidence: 99%

Adequacy of inhale/exhale breathhold CT based ITV margins and image-guided registration for free-breathing pancreas and liver SBRT

et al. 2014

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PurposeTo evaluate use of breath-hold CTs and implanted fiducials for definition of the internal target volume (ITV) margin for upper abdominal stereotactic body radiation therapy (SBRT). To study the statistics of inter- and intra-fractional motion information.Methods and materials11 patients treated with SBRT for locally advanced pancreatic cancer (LAPC) or liver cancer were included in the study. Patients underwent fiducial implantation, free-breathing CT and breath-hold CTs at end inhalation/exhalation. All patients were planned and treated with SBRT using volumetric modulated arc therapy (VMAT). Two margin strategies were studied: Strategy I uses PTV = ITV + 3 mm; Strategy II uses PTV = GTV + 1.5 cm. Both CBCT and kV orthogonal images were taken and analyzed for setup before patient treatments. Tumor motion statistics based on skeletal registration and on fiducial registration were analyzed by fitting to Gaussian functions.ResultsAll 11 patients met SBRT planning dose constraints using strategy I. Average ITV margins for the 11 patients were 2 mm RL, 6 mm AP, and 6 mm SI. Skeletal registration resulted in high probability (RL = 69%, AP = 4.6%, SI = 39%) that part of the tumor will be outside the ITV. With the 3 mm ITV expansion (Strategy 1), the probability reduced to RL 32%, AP 0.3%, SI 20% for skeletal registration; and RL 1.2%, AP 0%, SI 7% for fiducial registration. All 7 pancreatic patients and 2 liver patients failed to meet SBRT dose constraints using strategy II. The liver dose was increased by 36% for the other 2 liver patients that met the SBRT dose constraints with strategy II.ConclusionsImage guidance matching to skeletal anatomy is inadequate for SBRT positioning in the upper abdomen and usage of fiducials is highly recommended. Even with fiducial implantation and definition of an ITV, a minimal 3 mm planning margin around the ITV is needed to accommodate intra-fractional uncertainties.

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“…Another study assessed interfractional breath‐hold reproducibility in ten patients (18) . Recently, repeated 4D CT was applied to fifteen patients, using intrapancreatic bile ducts as a surrogate for pancreatic position during free‐breathing (19) . These studies concluded that interfractional positional variation was not negligible and that interfractional reproducibility was higher at end‐exhalation then at end‐inhalation.…”

Section: Discussionmentioning

confidence: 99%

Free‐breathing conformal irradiation of pancreatic cancer

Solla

Zucca

Possanzini

et al. 2013

J Applied Clin Med Phys

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The purpose of this study was to assess treatment margins in free‐breathing irradiation of pancreatic cancer after bone alignment, and evaluate their impact on conformal radiotherapy. Fifteen patients with adenocarcinoma of the head of the pancreas underwent implantation of single fiducial marker. Intrafraction uncertainties were assessed on simulation four‐dimensional computed tomography (4D CT) by calculating maximal intrafraction fiducial excursion (MIFE). In the first ten patients, after bony alignment, the position of the fiducial was identified on weekly acquired megavolt cone‐beam CT (MV‐CBCT). The interfraction residual uncertainties were estimated by measuring the fiducial displacements with respect to the position in the first session. Patient mean (pM) and patient standard deviation (pSD) of fiducial displacement, mean (μnormalM) and standard deviation (μSD) of pM, and root‐mean‐square of pSD (σres) were calculated. In the other five patients, MIFE was added to the residual component to obtain personalized margin. In these patients, conformal kidney sparing (CONKISS) irradiation was planned prescribing 54/45 Gy to PTV1/PTV2. The organ‐at‐risk limits were set according to current NCCN recommendation. No morbidity related to the fiducial marker implantation was recorded. In the first ten patients, along right–left, anterior–posterior, and inferior–superior directions, MIFE was variable (mean±std=0.24±0.13.2emcm,0.31±0.14.2emcm,0.83±0.35.2emcm, respectively) and was at most 0.51, 0.53, and 1.56 cm, respectively. Along the same directions, μnormalM were 0.09,−0.05,−0.05.2emcm,μSD were 0.30, 0.17, 0.33 cm, and σres were 0.35, 0.26, and 0.30 cm, respectively. MIFE was not correlated with pM and pSD. In the five additional patients, it was possible to satisfy recommended dose limits, with the exception of slightly higher doses to small bowel. After bony alignment, the margins for target expansion can be obtained by adding personalized MIFE to the residual interfraction term. Using these margins, conformal free‐breathing irradiation is a reliable option for the treatment of pancreatic cancer.PACS number: 87.55.D‐

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Interfractional Reproducibility in Pancreatic Position Based on Four-Dimensional Computed Tomography

Cited by 17 publications

References 33 publications

Modeling Pancreatic Tumor Motion Using 4-Dimensional Computed Tomography and Surrogate Markers

Modeling Pancreatic Tumor Motion Using 4-Dimensional Computed Tomography and Surrogate Markers

Adequacy of inhale/exhale breathhold CT based ITV margins and image-guided registration for free-breathing pancreas and liver SBRT

Free‐breathing conformal irradiation of pancreatic cancer

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