Quantifying dose perturbations in high-risk prostate radiotherapy due to translational and rotational motion of prostate and pelvic lymph nodes.

Background: Radiotherapy of the prostate and the pelvic lymph nodes (LN) is a part of the standard of care treatment for high-risk prostate cancer. The independent translational and rotational (i.e.

The dosimetric error due to uncorrected tumor rotation during real-time adaptive prostate stereotactic body radiation therapy.

Background: During prostate stereotactic body radiation therapy (SBRT), prostate tumor translational motion may deteriorate the planned dose distribution. Most of the major advances in motion management to date have focused on correcting this one aspect of the tumor motion, translation. However, large prostate rotation up to 30° has been measured.

Experimental investigation of dynamic real-time rotation-including dose reconstruction during prostate tracking radiotherapy.

Background: Hypofractionation in prostate radiotherapy is of increasing interest. Steep dose gradients and a large weight on each individual fraction emphasize the need for motion management. Real-time motion management techniques such as multileaf collimator (MLC) tracking or couch tracking typically adjust for translational motion while rotations remain uncompensated with unknown dosimetric impact.

Real-time dose-guidance in radiotherapy: Proof of principle.

Purpose: The outcome of radiotherapy is a direct consequence of the dose delivered to the patient. Yet image-guidance and motion management to date focus on geometrical considerations as a practical surrogate for dose. Here, we propose real-time dose-guidance realized through continuous motion-including dose reconstructions and demonstrate this new concept in simulated liver stereotactic body radiotherapy (SBRT) delivery.

Six degrees of freedom dynamic motion-including dose reconstruction in a commercial treatment planning system.

Purpose: Intrafractional motion during radiotherapy delivery can deteriorate the delivered dose. Dynamic rotational motion of up to 38 degrees has been reported during prostate cancer radiotherapy, but methods to determine the dosimetric consequences of such rotations are lacking. Here, we create and experimentally validate a dose reconstruction method that accounts for dynamic rotations and translations in a commercial treatment planning system (TPS).

Dosimetric impact of intrafraction prostate rotation and accuracy of gating, multi-leaf collimator tracking and couch tracking to manage rotation: An end-to-end validation using volumetric film measurements.

Background And Purpose: Both gating and tracking can mitigate the deteriorating dosimetric impact of intrafraction translation during prostate stereotactic body radiotherapy (SBRT). However, their ability to manage intrafraction rotation has not yet been thoroughly investigated. The dosimetric accuracy of gating, MLC tracking and couch tracking to manage intrafraction prostate rotation was investigated.

Simulated real-time dose reconstruction for moving tumors in stereotactic liver radiotherapy.

Purpose: In radiotherapy, tumor motion may deteriorate the planned dose distribution. However, the dosimetric consequences of the motion are normally unknown for individual treatments. We here present a method for real-time motion-including tumor dose reconstruction and demonstrate its use for simulated stereotactic body radiotherapy (SBRT) of patients with liver cancer previously treated with Calypso-guided gating.

First clinical real-time motion-including tumor dose reconstruction during radiotherapy delivery.

Purpose: To clinically implement and characterize real-time motion-including tumor dose reconstruction during radiotherapy delivery.

Methods: Seven patients with 2-3 fiducial markers implanted near liver tumors received stereotactic body radiotherapy on a conventional linear accelerator. The 3D marker motion during a setup CBCT scan was determined online from the CBCT projections and used to generate a correlation model between tumor and external marker block motion.

Validation of fast motion-including dose reconstruction for proton scanning therapy in the liver.

This study validates a method of fast motion-including dose reconstruction for proton pencil beam scanning in the liver. The method utilizes a commercial treatment planning system (TPS) and calculates the delivered dose for any translational 3D target motion. Data from ten liver patients previously treated with photon radiotherapy with intrafraction tumour motion monitoring were used.

First online real-time evaluation of motion-induced 4D dose errors during radiotherapy delivery.

Purpose: In radiotherapy, dose deficits caused by tumor motion often far outweigh the discrepancies typically allowed in plan-specific quality assurance (QA). Yet, tumor motion is not usually included in present QA. We here present a novel method for online treatment verification by real-time motion-including four-dimensional (4D) dose reconstruction and dose evaluation and demonstrate its use during stereotactic body radiotherapy (SBRT) delivery with and without MLC tracking.