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

Background: Pencil 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.

Accuracy and potential improvements of surface-guided breast cancer radiotherapy in deep inspiration breath-hold with daily image-guidance.

Radiotherapy of left-sided breast cancer in deep inspiration breath-hold (DIBH) reduces the heart dose. Surface guided radiotherapy (SGRT) can guide the DIBH, but the accuracy is subject to variations in the chest wall position relative to the patient surface.In this study, ten left-sided breast cancer patients received DIBH radiotherapy with tangential fields in 15-18 fractions.

Geometric and dosimetric comparison of four intrafraction motion adaptation strategies for stereotactic liver radiotherapy.

The accuracy of stereotactic body radiotherapy (SBRT) in the liver is limited by tumor motion. Selection of the most suitable motion mitigation strategy requires good understanding of the geometric and dosimetric consequences. This study compares the geometric and dosimetric accuracy of actually delivered respiratory gated SBRT treatments for 15 patients with liver tumors with three simulated alternative motion adaptation strategies.

Investigation of the optimum location of external markers for patient setup accuracy enhancement at external beam radiotherapy.

In external beam radiotherapy, one of the most common and reliable methods for patient geometrical setup and/or predicting the tumor location is use of external markers. In this study, the main challenging issue is increasing the accuracy of patient setup by investigating external markers location. Since the location of each external marker may yield different patient setup accuracy, it is important to assess different locations of external markers using appropriate selective algorithms.

Optimum location of external markers using feature selection algorithms for real-time tumor tracking in external-beam radiotherapy: a virtual phantom study.

In external-beam radiotherapy, using external markers is one of the most reliable tools to predict tumor position, in clinical applications. The main challenge in this approach is tumor motion tracking with highest accuracy that depends heavily on external markers location, and this issue is the objective of this study. Four commercially available feature selection algorithms entitled 1) Correlation-based Feature Selection, 2) Classifier, 3) Principal Components, and 4) Relief were proposed to find optimum location of external markers in combination with two "Genetic" and "Ranker" searching procedures.

A Feasibility Study on Ribs as Anatomical Landmarks for Motion Tracking of Lung and Liver Tumors at External Beam Radiotherapy.

At external beam radiotherapy for some tumors located at thorax region due to lack of information in gray scale fluoroscopic images tumor position determination is problematic. One of the clinical strategies is to implant clip as internal fiducial marker inside or near tumor to represent tumor position while the contrast of implanted clip is highly observable rather than tumor. As alternative, using natural anatomical landmarks located at thorax region of patient body is proposed to extract tumor position information without implanting clips that is invasive method with possible side effect.