Intrafractional relationship changes between an external breathing signal and fiducial marker positions in pancreatic cancer patients

Pettersson, Niclas; Oderinde, O.M.; Murphy, James D.; Simpson, Daniel R.; Cerviño, Laura

doi:10.1002/acm2.12841

Cited by 6 publications

(5 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although an ECM of the day was built, the accuracy cannot be expected to be better than the ECM fit, which had mean RMS errors of almost half of the treatment errors and exceeding 2 mm in the CC direction for one patient (Table 1). Furthermore, high intrafraction stability of the ECM with the ability to detect internal baseline shift cannot in general be assumed (43)(44)(45)(46). Optimally, the ECM should be built based on the setup CBCT and then validated by the post-treatment CBCT.…”

Section: Discussionmentioning

confidence: 99%

Intrafraction tumor motion monitoring and dose reconstruction for liver pencil beam scanning proton therapy

Nankali

Worm²,

Thomsen³

et al. 2023

Front. Oncol.

View full text Add to dashboard Cite

BackgroundPencil beam scanning (PBS) proton therapy can provide highly conformal target dose distributions and healthy tissue sparing. However, proton therapy of hepatocellular carcinoma (HCC) is prone to dosimetrical uncertainties induced by respiratory motion. This study aims to develop intra-treatment tumor motion monitoring during respiratory gated proton therapy and combine it with motion-including dose reconstruction to estimate the delivered tumor doses for individual HCC treatment fractions.MethodsThree HCC-patients were planned to receive 58 GyRBE (n=2) or 67.5 GyRBE (n=1) of exhale respiratory gated PBS proton therapy in 15 fractions. The treatment planning was based on the exhale phase of a 4-dimensional CT scan. Daily setup was based on cone-beam CT (CBCT) imaging of three implanted fiducial markers. An external marker block (RPM) on the patient’s abdomen was used for exhale gating in free breathing. This study was based on 5 fractions (patient 1), 1 fraction (patient 2) and 6 fractions (patient 3) where a post-treatment control CBCT was available. After treatment, segmented 2D marker positions in the post-treatment CBCT projections provided the estimated 3D motion trajectory during the CBCT by a probability-based method. An external-internal correlation model (ECM) that estimated the tumor motion from the RPM motion was built from the synchronized RPM signal and marker motion in the CBCT. The ECM was then used to estimate intra-treatment tumor motion. Finally, the motion-including CTV dose was estimated using a dose reconstruction method that emulates tumor motion in beam’s eye view as lateral spot shifts and in-depth motion as changes in the proton beam energy. The CTV homogeneity index (HI) The CTV homogeneity index (HI) was calculated as D2% − D98%D50% ×100%.ResultsThe tumor position during spot delivery had a root-mean-square error of 1.3 mm in left-right, 2.8 mm in cranio-caudal and 1.7 mm in anterior-posterior directions compared to the planned position. On average, the CTV HI was larger than planned by 3.7%-points (range: 1.0-6.6%-points) for individual fractions and by 0.7%-points (range: 0.3-1.1%-points) for the average dose of 5 or 6 fractions.ConclusionsA method to estimate internal tumor motion and reconstruct the motion-including fraction dose for PBS proton therapy of HCC was developed and demonstrated successfully clinically.

show abstract

Section: Discussionmentioning

confidence: 99%

Intrafraction tumor motion monitoring and dose reconstruction for liver pencil beam scanning proton therapy

Nankali

Worm²,

Thomsen³

et al. 2023

Front. Oncol.

View full text Add to dashboard Cite

show abstract

“…For example, the distance and spatial relationship between multiple implant fiducials and tumors may change because of the treatment and/or disease-related organ swelling or contraction. In addition, due to the differential movement caused by organ deformation, the distance between fiducials and the tumor may change during the respiratory cycle ( 26 ).…”

Section: Discussionmentioning

confidence: 99%

Study on Motion Management of Pancreatic Cancer Treated by CyberKnife

Shenghua

Jiang

et al. 2021

Front. Oncol.

View full text Add to dashboard Cite

PurposeWe investigated the movement characteristics of pancreas and the clinical accuracy of tracking pancreas with the Synchrony Respiratory Tracking System (SRTS) during the CyberKnife treatment. These data provide a clinical data basis for the expansion margins of pancreatic tumor target.Methods and MaterialsForty-two patients with pancreatic cancer treated by CyberKnife were retrospectively studied. The pancreatic displacement calculated from the x-ray images collected during the time interval between two consecutive movements constituted a data set.ResultsThe total mean motion amplitudes and standard deviations of pancreatic tumors in SI, LR, AP, and radial directions were 3.66 ± 1.71 mm, 0.97 ± 0.62 mm, 1.52 ± 1.02 mm, and 1.36 ± 0.49 mm, respectively. The overall mean correlation errors and standard deviations were 0.82 ± 0.46 mm, 0.47 ± 0.33 mm, 0.41 ± 0.24 mm, and 0.98 ± 0.37 mm, respectively. The overall mean prediction errors and standard deviations were 0.57 ± 0.14 mm, 0.62 ± 0.28 mm, 0.39 ± 0.17 mm, and 1.58 ± 0.36 mm, respectively. The correlation errors and prediction errors of pancreatic tumors at different anatomical positions in SI, LR, and AP directions were statistically significant (p < 0.05).ConclusionsThe tumor motion amplitude, the tumor location, and the treatment time are the main factors affecting the tracking accuracy. The pancreatic tumors at different anatomical locations should be treated differently to ensure sufficient dose coverage of the pancreatic target area.

show abstract

“…There are many reports on internal errors in external radiation therapy for LAPC, 17 , 18 , 19 , 20 and many problems need to be solved. It has been pointed out that changes in GI tract density are more affected by particle therapy.…”

Section: Discussionmentioning

confidence: 99%

Dosimetric impact of simulated changes in large bowel content during proton therapy with simultaneous integrated boost for locally advanced pancreatic cancer

Narita

Katō

Takemasa

et al. 2021

J Applied Clin Med Phys

View full text Add to dashboard Cite

To investigate the dosimetric impact of changes in the large bowel content during proton therapy (PT) with simultaneous integrated boost (SIB) for locally advanced pancreatic cancer (LAPC). Materials and methods: Fifteen patients with LAPC were included in this study. The SIB method was performed using five fields according to our standard protocol. A total dose of 67.5 Gy(relative biological effectiveness [RBE]) was prescribed in 25 fractions using the SIB method. A dose of 45 Gy(RBE) was prescribed for the entire planning target volume (PTV) by using four main fields. The remaining 22.5 Gy(RBE) was prescribed to the PTV excluding for the gastrointestinal tract using one subfield. Five simulated doses were obtained by the forward dose calculations with the Hounsfield units (HU) override to the large bowel to 50, 0, −100, −500, and −1000, respectively. The dose-volume indices in each plan were compared using the 50 HU plan as a reference. Results: At D 98 of the clinical target volume (CTV) and spinal cord-D 2cc , when the density of the large bowel was close to that of gas, there were significant differences compared to the reference plan (p < 0.05). By contrast, no significant difference was observed in stomach-D 2cc duodenum-D 2cc , small bowel-D 2cc , kidneys-V 18 , and liver-D mean under any of the conditions. There were no cases in which the dose constraint of organs at risk, specified by our institution, was exceeded. Conclusion: Density change in the large bowel was revealed to significantly affect the doses of the CTV and spinal cord during PT with SIB for LAPC. For beam arrangement,it is important to select a gantry angle that prevents the large bowel from passing as much as possible. If this is unavoidable, it is important to carefully observe the gas image on the beam path during daily image guidance and to provide adaptive re-planning as needed.

show abstract

Intrafractional relationship changes between an external breathing signal and fiducial marker positions in pancreatic cancer patients

Cited by 6 publications

References 17 publications

Intrafraction tumor motion monitoring and dose reconstruction for liver pencil beam scanning proton therapy

Intrafraction tumor motion monitoring and dose reconstruction for liver pencil beam scanning proton therapy

Study on Motion Management of Pancreatic Cancer Treated by CyberKnife

Dosimetric impact of simulated changes in large bowel content during proton therapy with simultaneous integrated boost for locally advanced pancreatic cancer

Contact Info

Product

Resources

About