SU-FF-T-300: Investigation of Respiratory Motion Effect On Lung Tumor Radiotherapy Using 4D Monte Carlo Treatment Planning and 4D CT

2006 ◽  
Vol 33 (6Part11) ◽  
pp. 2115-2115
Author(s):  
M Ding ◽  
L Xing ◽  
F Newman
Keyword(s):  
Monte Carlo ◽  
Treatment Planning ◽  
Respiratory Motion ◽  
Lung Tumor ◽  
4D Ct ◽  
Motion Effect

scholarly journals Dynamic MLC Tracking Using 4D Lung Tumor Motion Modelling and EPID Feedback

2018 ◽  
Author(s):  
N Rostampour ◽  
K Jabbari ◽  
Sh Nabavi ◽  
M Mohammadi ◽  
M Esmaeili
Keyword(s):  
Respiratory Motion ◽  
Lung Tumor ◽  
Statistical Criterion ◽  
Mean Square ◽  
Tumor Motion ◽  
4D Ct ◽  
Improve Treatment ◽  
Neuro Fuzzy ◽  
Targeting Accuracy ◽  
Good Agreement

Background: Respiratory motion causes thoracic movement and reduces targeting accuracy in radiotherapy.Objective: This study proposes an approach to generate a model to track lung tumor motion by controlling dynamic multi-leaf collimators.Material and Methods: All slices which contained tumor were contoured in the 4D-CT images for 10 patients. For modelling of respiratory motion, the end-exhale phase of these images has been considered as the reference and they were analyzed using neuro-fuzzy method to predict the magnitude of displacement of the lung tumor. Then, the predicted data were used to determine the leaf motion in MLC. Finally, the trained algorithm was figured out using Shaper software to show how MLCs could track the moving tumor and then imported on the Varian Linac equipped with EPID.Results: The root mean square error (RMSE) was used as a statistical criterion in order to investigate the accuracy of neuro-fuzzy performance in lung tumor prediction. The results showed that RMSE did not have a considerable variation. Also, there was a good agreement between the images obtained by EPID and Shaper for a respiratory cycle.Conclusion: The approach used in this study can track the moving tumor with MLC based on the 4D modelling, so it can improve treatment accuracy, dose conformity and sparing of healthy tissues because of low error in margins that can be ignored. Therefore, this method can work more accurately as compared with the gating and invasive approaches using markers.

scholarly journals CT Protocols for Attenuation Correction and Segmentation in 99mTc-MAA SPECT/CT for 90Y Radioembolization Treatment Planning – a Simulation Study

2020 ◽  
Author(s):  
Zhonglin Lu ◽  
Greta S. P. Mok
Keyword(s):  
Treatment Planning ◽  
Attenuation Correction ◽  
Respiratory Motion ◽  
Absorbed Dose ◽  
Normal Liver ◽  
Detector Response ◽  
Dose Estimation ◽  
Respiratory Motion Artifact ◽  
4D Ct ◽  
Significant Difference

Abstract Background Conventional 99mTc-macroaggregated albumin (99mTc-MAA) planar scintigraphy overestimates lung shunt fraction (LSF) as compared to SPECT/CT in 90Y radioembolization treatment planning. However, the respiratory motion artifact due to the temporal mismatch between static SPECT and helical CT (HCT) may compromise the SPECT quantitation accuracy by incorrect attenuation correction (AC) and volume-of-interest segmentation. The goal of this study is to systematically assess different AC and segmentation protocols for LSF, tumor-to-normal liver (TNR), organ absorbed dose and injected activity (IA) estimation in 99mTc-MAA SPECT/CT.Methods The 4D XCAT phantom was used to simulate 10 patient anatomies with 99mTc-MAA distribution based on the clinical data, each with LSF of 5%, 10%, 15% and 20%, axial respiratory motion of 2 cm, different TNR and tumor size. An analytical projector for low energy high resolution parallel-hole collimator was used to simulate realistic noisy planar acquisitions, and 128 projections over 360o for SPECT, both modeling attenuation, scatter and geometric collimator-detector-response. Five attenuation maps, i.e., (i) HCT at end-inspiration (HCT-IN), (ii) HCT at mid-respiration (HCT-MID), (iii) HCT at end-expiration (HCT-EX), (iv) cine averaged CT (CACT) and (v) interpolated average CT (IACT) were applied for SPECT AC and segmentation in LSF, dosimetric and IA evaluation. Mid-respiratory phases were also extracted from CACT/IACT for VOI segmentation while CACT/IACT were used for AC, i.e., hybrid CT protocols.Results For LSF estimation, SPECT/CACT has the least absolute errors. Planar significantly overestimates LSF and lung absorbed dose compared to SPECT especially for LSF of 5%. SPECT-based is better than CT-based segmentation in TNR estimation. There is no statistically significant difference for different CT protocols for TNR, normal liver and tumor absorbed dose estimation. Hybrid CTs and HCT-MID performed the best for IA especially for higher LSF.Conclusions 99mTc-MAA SPECT/CT with an appropriate choice of CT protocol for AC and segmentation is superior to planar in LSF and lung absorbed dose estimation. The 4D CT protocols are recommended for AC and segmentation to alleviate respiratory artifacts and improve quantitation accuracy in 90Y radioembolization treatment planning. HCT-EX would also be a recommended choice if 4D CT is not available.

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