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Cranial irradiation is associated with significant neurocognitive sequelae, secondary to radiation-induced damage to hippocampal cells. It has been shown that hippocampal-sparing (HS) leads to modest benefit in neurocognitive function in patients with brain metastases, but further improvement is possible. We hypothesized that improved benefits could be seen using HS in patients treated with stereotactic radiation (HS-SRS). Our study evaluated whether the hippocampal dose could be significantly reduced in the treatment of brain metastases using SRS, while maintaining target coverage.

Sixty SRS plans were re-planned to minimize dose to the hippocampus while maintaining target coverage. Patients with metastases within 5mm of the hippocampus were excluded. Minimum, mean, maximum and dose to 40% (mean equivalent dose in 2Gy per fraction, EQD

to the hippocampus) were compared between SRS and HS-SRS plans. Median number of brain metastases was two.

Compared to baseline SRS plans, hippocampal-sparing plans demonstrated D

was reduced by 35%, from 0.4Gy to 0.3Gy (p-value 0.02). Similarly, D

was reduced by 55%, from 8.2Gy to 3.6Gy, D

by 52%, from 1.6Gy to 0.5Gy, and D

by 50%, from 1.8Gy to 0.9Gy (p-values <0.001).

Our study demonstrated that further reduction of hippocampal doses of more than 50% is possible in the treatment of brain metastases with SRS using dose optimization. This could result in significantly improved neurocognitive outcomes for patients treated for brain metastases.

Our study demonstrated that further reduction of hippocampal doses of more than 50% is possible in the treatment of brain metastases with SRS using dose optimization. This could result in significantly improved neurocognitive outcomes for patients treated for brain metastases.

Longitudinal Positron Emission Tomography (PET) with hypoxia-specific radiotracers allows monitoring the time evolution of regions of increased radioresistance and may become fundamental in determining the radiochemotherapy outcome in Head-and-Neck Squamous Cell Carcinoma (HNSCC). The aim of this study was to investigate the evolution of the hypoxic target volume on oxygen partial pressure maps (pO

-HTV) derived from

FMISO-PET images acquired before and during radiochemotherapy and to uncover correlations between extent and severity of hypoxia and treatment outcome.

FMISO-PET/CT images were acquired at three time points (before treatment start, in weeks two and five) for twenty-eight HNSCC patients treated with radiochemotherapy. The images were converted into pO

maps and corresponding pO

-HTVs (pO

-HTV

, pO

-HTV

, pO

-HTV

) were contoured at 10mmHg. Different parameters describing the pO

-HTV time evolution were considered, such as the percent and absolute difference between the pO

-HTVs (%HTV

and HTV

-HTV

with i,j=1, 2, 3, respectively) and the slope of the linear regression curve fitting the pO

-HTVs in time. Correlations were sought between the pO

-HTV evolution parameters and loco-regional recurrence (LRR) using the Receiver Operating Characteristic method.

The Area Under the Curve values for %HTV

, HTV

-HTV

, HTV

-HTV

and the slope of the pO

-HTV linear regression curve were 0.75 (p=0.04), 0.73 (p=0.02), 0.73 (p=0.02) and 0.75 (p=0.007), respectively. #link# Other parameter combinations were not statistically significant.

The pO

-HTV evolution during radiochemotherapy showed predictive value for LRR. The changes in the tumour hypoxia during the first two treatment weeks may be used for adaptive personalized treatment approaches.

The pO2-HTV evolution during radiochemotherapy showed predictive value for LRR. The changes in the tumour hypoxia during the first two treatment weeks may be used for adaptive personalized treatment approaches.Magnetic resonance (MR)-only workflows require quality assurance due to potential dosimetric impacts of using geometry distorted MR images in radiotherapy planning. MR-visible silicone-based fiducials were arranged in regular 3D structures to cover extended imaging volumes. The scanner’s patient marking workflow with a 2-axes movable laser bridge allowed to visually check geometric distortions of each MR reconstructed fiducial against its true position in 3D space. A measurement resolution and uncertainty of the order of 0.5 mm in sagittal and coronal, and 1 mm in transversal direction was found. The proposed workflow required 1 min of evaluation time per fiducial position, and a 9 min 3D MR volume acquisition.This study reports dose corresponding to visible radiation induced liver damage following Stereotactic Body Radiation Therapy (SBRT) for liver metastasis, and the optimal time for follow up scans using post radiation imaging. Diagnostic magnetic resonance scans of nine patients treated with liver SBRT using a 0.35 T MRI-guided radiotherapy system were analyzed. The dice coefficients between the region of visible liver damage and the delivered dose were calculated. A median dose of 35 Gy correlated most closely with the visible radiation induced liver damage. We compared scans over two to nine months and observed maximal dice coefficients at two to five months post radiation. We have presented a new method for developing treatment planning guidelines for liver SBRT.

The more localized dose deposition of proton therapy (PT) compared to photon therapy might allow a reduction in treatment-related side effects but induces additional challenges to address. selleck products of this study was to evaluate the impact of interfractional motion on the target and organs at risk (OARs) in cervical cancer patients treated with spot scanning PT using an internal target volume (ITV) strategy.

For ten locally advanced cervical cancer patients, empty and full bladder planning computed tomography (pCT) as well as 25 daily cone beam CTs (CBCTs) were available. The Clinical Target Volume (CTV), the High Risk CTV (CTV

) (gross tumor volume and whole cervix), the non-involved uterus as well as the OARs (bowel, bladder and rectum) were contoured on the daily CBCTs and transferred to the pCT through rigid bony match. Using synthetic CTs derived from pCTs, four-beam spot scanning PT plans were generated to target the patient-specific ITV with 45Gy(RBE) in 25 fractions. This structure was defined based on pre-treatment MRI and CT to anticipate potential target motion throughout the treatment.