MRgRT real-time target localization using foundation models for contour point tracking and promptable mask refinement.

. This study aimed to evaluate two real-time target tracking approaches for magnetic resonance imaging (MRI) guided radiotherapy (MRgRT) based on foundation artificial intelligence models..

Artificial intelligence-assisted quantitative CT analysis of airway changes following SABR for central lung tumors.

Introduction: Use of stereotactic ablative radiotherapy (SABR) for central lung tumors can result in up to a 35% incidence of late pulmonary toxicity. We evaluated an automated scoring method to quantify post-SABR bronchial changes by using artificial intelligence (AI)-based airway segmentation.

Materials And Methods: Central lung SABR patients treated at Amsterdam UMC (AUMC, internal reference dataset) and Peter MacCallum Cancer Centre (PMCC, external validation dataset) were identified.

Clinical outcomes of MR-guided adrenal stereotactic ablative radiotherapy with preferential sparing of organs at risk.

Background And Purpose: The optimal stereotactic ablative radiotherapy (SABR) doses for adrenal tumors are unknown. Some trials have specified that organ at risk (OAR) dose constraints should take priority over target coverage. We performed a retrospective review of the outcomes of MR-guided adrenal SABR (MRgRT) delivered with OAR sparing.

Local control and toxicity after magnetic resonance imaging (MR)-guided single fraction lung stereotactic ablative radiotherapy.

Purpose: Magnetic resonance imaging (MR)-guided radiotherapy permits continuous intrafraction visualization and use of automatic triggered beam delivery, with use of smaller planning target volumes (PTV). We report on long-term clinical outcomes following MR-guided single fraction (SF) lung SABR on a 0.35 T linac.

Tumor volume changes during stereotactic ablative radiotherapy for adrenal gland metastases under MRI guidance.

Purpose: Gross tumor volume (GTV) changes during stereotactic ablative radiotherapy (SABR) for adrenal tumors are not well characterized. We studied treatment-induced GTV changes during, and after, 5-fraction MR-guided SABR on a 0.35 T unit.

Prediction of pathologic complete response after single-dose MR-guided partial breast irradiation in low-risk breast cancer patients: the ABLATIVE-2 trial-a study protocol.

Background: Partial breast irradiation (PBI) is standard of care in low-risk breast cancer patients after breast-conserving surgery (BCS). Pre-operative PBI can result in tumor downstaging and more precise target definition possibly resulting in less treatment-related toxicity. This study aims to assess the pathologic complete response (pCR) rate one year after MR-guided single-dose pre-operative PBI in low-risk breast cancer patients.

Comparison of MR-guided radiotherapy accumulated doses for central lung tumors with non-adaptive and online adaptive proton therapy.

Background: Stereotactic body radiation therapy (SBRT) of central lung tumors with photon or proton therapy has a risk of increased toxicity. Treatment planning studies comparing accumulated doses for state-of-the-art treatment techniques, such as MR-guided radiotherapy (MRgRT) and intensity modulated proton therapy (IMPT), are currently lacking.

Purpose: We conducted a comparison of accumulated doses for MRgRT, robustly optimized non-adaptive IMPT, and online adaptive IMPT for central lung tumors.

An ESTRO-ACROP guideline on quality assurance and medical physics commissioning of online MRI guided radiotherapy systems based on a consensus expert opinion.

Objective: The goal of this consensus expert opinion was to define quality assurance (QA) tests for online magnetic resonance image (MRI) guided radiotherapy (oMRgRT) systems and to define the important medical physics aspects for installation and commissioning of an oMRgRT system.

Materials And Methods: Ten medical physicists and two radiation oncologists experienced in oMRgRT participated in the survey. In the first round of the consensus expert opinion, ideas on QA and commissioning were collected.

Spontaneous ecchymoses.

The patient's lifestyle was undoubtedly to blame for the appearance of her skin. The loss of her beloved pet may have been a tipping point.

Same-day consultation, simulation and lung Stereotactic Ablative Radiotherapy delivery on a Magnetic Resonance-linac.

Background And Purpose: Magnetic resonance-guided radiotherapy (MRgRT) with real-time intra-fraction tumor motion monitoring allows for high precision Stereotactic Ablative Radiotherapy (SABR). This study aimed to investigate the clinical feasibility, patient satisfaction and delivery accuracy of single-fraction MR-guided SABR in a single day (one-stop-shop, OSS).

Methods And Materials: Ten patients with small lung tumors eligible for single fraction treatments were included.

Magnetic resonance imaging-guided radiotherapy for intermediate- and high-risk prostate cancer: Trade-off between planning target volume margin and online plan adaption.

Magnetic resonance-guided radiotherapy with daily plan adaptation for intermediate- and high-risk prostate cancer is time and labor intensive. Fifty adapted plans with 3 mm planning target volume (PTV)-margin were compared with non-adapted plans using 3 or 5 mm margins. Adequate (V95% ≥ 95%) prostate coverage was achieved in 49 fractions with 5 mm PTV without plan adaptation, however, coverage of the seminal vesicles (SV) was insufficient in 15 of 50 fractions.

Treatment patterns for adrenal metastases using surgery and SABR during a 10-year period.

We studied treatment patterns for adrenal metastases using surgery or SABR at a single institution during a 10-year period. The number of patients undergoing SABR doubled since 2016, without a change in numbers undergoing surgery. Both treatments resulted in low rates of acute toxicity and similar survivals.

Renal atrophy following gated delivery of stereotactic ablative radiotherapy to adrenal metastases.

Stereotactic ablative radiotherapy (SABR) planning for adrenal metastases aims to minimize doses to the adjacent kidney. Renal dose constraints for SABR delivery are not well defined. In 20 patients who underwent MR-guided breath-hold SABR in five daily fractions of 8-10 Gy, ipsilateral renal volumes receiving ≥20 Gy best correlated with loss of renal volumes, with median renal volume reduction being 6% (range: 3%-11%, 10th-90th percentiles).

Dose accumulation for personalized stereotactic MR-guided adaptive radiation therapy in prostate cancer.

Background And Purpose: Adaptive MR-guided radiotherapy (MRgRT) is an innovative approach for delivering stereotactic body radiotherapy (SBRT) in prostate cancer (PC). Despite the increased clinical use of SBRT for PC, there is limited data on the relation between the actual delivered dose and toxicity. We aimed to identify dose parameters based on the total accumulated delivered bladder dose (DOSE).

Delivery of magnetic resonance-guided single-fraction stereotactic lung radiotherapy.

Background And Purpose: Single-fraction stereotactic ablative radiotherapy (SABR) is an effective treatment for early-stage lung cancer, but concerns remain about the accurate delivery of SABR in a single session. We evaluated the delivery of single-fraction lung SABR using magnetic resonance (MR)-guidance.

Materials And Methods: An MR-simulation was performed in 17 patients, seven of whom were found to be unsuitable, largely due to unreliable tracking of small tumors.

The Role of Daily Adaptive Stereotactic MR-Guided Radiotherapy for Renal Cell Cancer.

Novel magnetic-resonance-guided radiotherapy (MRgRT) permits real-time soft-tissue visualization, respiratory-gated delivery with minimal safety margins, and time-consuming daily plan re-optimisation. We report on early clinical outcomes of MRgRT and routine plan re-optimization for large primary renal cell cancer (RCC). Thirty-six patients were treated with MRgRT in 40 Gy/5 fractions.

Changes in gastric anatomy after delivery of breath-hold MR-guided SABR for adrenal metastases.

Delivery of breath-hold MR-guided SABR is time-consuming, and the use of real-time tumor-tracking in a sagittal plane may fail to detect out-of-plane displacements of organs-at-risk. Analysis of daily MR-scans performed pre- and post-SABR revealed frequent decreases in stomach volumes, and in the planned stomach doses.

An end-to-end test for MR-guided online adaptive radiotherapy.

In the evolving field of adaptive MR guided radiotherapy, the need for dedicated procedures for acceptance and quality assurance is increasing. Research has been devoted to MR compatible dosimeters and phantoms, but to date no end-to-end test has been presented that covers an MRgRT workflow. Such an end-to-end test should comprise each step of the workflow and include all associated uncertainties.

Clinical Outcomes of Stereotactic MR-Guided Adaptive Radiation Therapy for High-Risk Lung Tumors.

Purpose: Magnetic resonance (MR)-guided SABR was performed for patients with lung tumors in whom treatment delivery was challenging owing to tumor location, motion, or pulmonary comorbidity. Because stereotactic MR-guided adaptive radiation therapy (SMART) is a novel approach, we studied clinical outcomes in these high-risk lung tumors.

Methods And Materials: Fifty consecutive patients (54 lung tumors) underwent SMART between 2016 and 2018 for either a primary lung cancer (29 patients) or for lung metastases (21 patients).

Stereotactic MR-guided adaptive radiation therapy for peripheral lung tumors.

Background And Purpose: We studied the benefits of using stereotactic MR-guided adaptive radiation therapy (SMART) for delivery of SABR in peripherally located lung tumors.

Methods And Materials: Twenty-three patients (25 peripheral lung tumors) underwent SMART in 3-8 fractions on an MR Linac or Cobalt-60 system. Before each fraction, a breath-hold MR scan was acquired, followed by on-table plan adaptation based on the anatomy-of-the-day.

End-to-end empirical validation of dose accumulation in MRI-guided adaptive radiotherapy for prostate cancer using an anthropomorphic deformable pelvis phantom.

Background And Purpose: This work evaluates the accuracy of deformable dose accumulation for organs at risk (OAR) in MR-guided prostate SBRT using an anthropomorphic deformable phantom.

Materials And Methods: Six MR-guided prostate SBRT treatment courses were simulated using volumetric OAR (bladder and rectum) information derived from actual patient data. Deformed OAR contours, geometrical landmarks and GafChromic EBT3 film strips (1.

MRI in medical practice and its future use in radiation oncology. Resume of XXV GOCO Congress (Montpellier) 2017.

This publication is a resume of the GOCO Congress (Montpellier 2017). A part of this congress was about the use of MRI in clinical practice, focused on the oncology field. The role of this tool was described in diagnosis, staging of tumors, evaluation of treatment response and the future use in prognostic and investigation (radiomics).