Definition of a framework for volumetric modulated arc therapy plan quality assessment with integration of dose-, complexity-, and robustness metrics.

Background And Purpose: Conventionally, the quality of radiotherapy treatment plans is assessed through visual inspection of dose distributions and dose-volume histograms. This study developed a framework to evaluate plan quality using dose, complexity, and robustness metrics. Additionally, a method for predicting plan robustness metrics using dose and complexity metrics was introduced for cases where plan robustness evaluation is unavailable or impractical.

Forest tree growth is linked to mycorrhizal fungal composition and function across Europe.

Most trees form symbioses with ectomycorrhizal fungi (EMF) which influence access to growth-limiting soil resources. Mesocosm experiments repeatedly show that EMF species differentially affect plant development, yet whether these effects ripple up to influence the growth of entire forests remains unknown. Here we tested the effects of EMF composition and functional genes relative to variation in well-known drivers of tree growth by combining paired molecular EMF surveys with high-resolution forest inventory data across 15 European countries.

Radiosurgery with flattening-filter-free techniques in the treatment of brain metastases : Plan comparison and early clinical evaluation.

Background: Radiosurgical treatment of brain metastases is well established in daily clinical routine. Utilization of flattening-filter-free beams (FFF) may allow for more rapid delivery of treatment doses and improve clinical comfort. Hence, we compared plan quality and efficiency of radiosurgery in FFF mode to FF techniques.

Establishing stereotactic body radiotherapy with flattening filter free techniques in the treatment of pulmonary lesions - initial experiences from a single institution.

Background: Stereotactic body radiotherapy (SBRT) using flattening filter free (FFF)-techniques has been increasingly applied during the last years. However, clinical studies investigating this emerging technique are still rare. Hence, we analyzed toxicity and clinical outcome of pulmonary SBRT with FFF-techniques and performed dosimetric comparison to conventional techniques using flattening filters (FF).

Long-term outcome after highly advanced single-dose or fractionated radiotherapy in patients with vestibular schwannomas - pooled results from 3 large German centers.

Purpose: To evaluate long-term clinical outcome and determine prognostic factors for local-control, hearing preservation and cranial nerve toxicity in 449 patients treated for 451 vestibular schwannomas (VS) with radiosurgery (n=169; 38%) or fractionated stereotactic radiotherapy (FSRT; n=291; 62%).

Methods And Materials: 245 patients were male (55%), and 204 were female (45%). Median age was 60 years (range 17-88 years).

pH-dependent nano-capturing of tartaric acid using dendrimers.

The ability of dendrimers to bind to various target molecules through non-covalent interactions was used to capture water soluble organic reagents, such as tartaric acid (TA), from different matrices, i.e. aqueous solutions and wine samples.

Accuracy quantification of a deformable image registration tool applied in a clinical setting.

The purpose of this study was to test the accuracy of a commercially available deformable image registration tool in a clinical situation. In addition, to demonstrate a method to evaluate the resulting transformation of such a tool to a reference defined by multiple experts. For 16 patients (seven head and neck, four thoracic, five abdominal), 30-50 anatomical landmarks were defined on recognizable spots of a planning CT and a corresponding fraction CT.

Tomotherapy radiosurgery for arteriovenous malformations--current possibilities and future options with helical tomotherapy dynamic jaws?

This planning study was performed to compare stereotactic linac based radiosurgery of Arteriovenous Malformations (AVM) with current Helical Tomotherapy (HT) and future HT techniques. For 10 patients with AVM, dose distributions and treatment times of "regular" HT delivery (Reg 2.5/1/0.

Hearing preservation after radiotherapy for vestibular schwannomas is comparable to hearing deterioration in healthy adults and is accompanied by local tumor control and a highly preserved quality of life (QOL) as patients' self-reported outcome.

Purpose: To evaluate long-term results and patients' self-reported outcome of high-precision photon radiotherapy for the treatment of patients with vestibular schwannoma (VS).

Methods And Materials: We treated 246 patients with 248 VS with fractionated stereotactic radiotherapy (FSRT) or stereotactic radiosurgery (SRS). For FSRT, a median total dose of 57.

Definitive Radiotherapy versus Postoperative Radiotherapy of Patients with Oro- and Hypopharyngeal Cancer: Impact of Prognostic Factors.

Purpose. To compare the impact of prognostic factors of patients treated with definitive radio(chemo)therapy versus patients treated with surgery and postoperative radiotherapy for squamous cell carcinoma of the oro- and hypopharynx. Patients and Methods.

Influence of intravenous contrast agent on dose calculation in 3-D treatment planning for radiosurgery of cerebral arteriovenous malformations.

Purpose: To investigate the influence of local density increase by i.v. contrast agent on dose calculation in linac-based radiosurgery (RS) of cerebral arteriovenous malformations (AVMs).

Contrast-enhanced color duplex sonography (CDS): an alternative for the evaluation of therapy-relevant tumor oxygenation?

Purpose: To evaluate the predictive value of radiotherapeutically relevant tumor hypoxia by contrast-enhanced color duplex sonography (CDS). The objectification was based on pO(2) histography.

Material And Methods: 25 patients with metastatic neck lymph node from a primary squamous carcinoma of the head and neck were examined.

Coupling-isomerization-N,S-ketene acetal-addition sequences--a three-component approach to highly fluorescent pyrrolo[2,3-b]pyridines, [1,8]naphthyridines, and pyrido[2,3-b]azepines.

Annelated 2-amino pyridines such as pyrrolo[2,3-b]pyridines, [1,8]naphthyridines, and pyrido[2,3-b]azepines can be synthesized in moderate to good yields in a consecutive one-pot three-component process by a coupling-isomerization-enamine-addition-cyclocondensation sequence of an electron-poor (hetero)aryl halide, a terminal propargyl N-tosylamine, and an N,S-ketene acetal. After the coupling-isomerization sequence, a Diels-Alder reaction with inverse electron demand of the intermediate enimine and the N,S-ketene acetal and subsequent aromatization furnish annelated 2-amino pyridines 4 that were unambiguously characterized by numerous X-ray structure analyses. These heterocycles are highly fluorescent and partially pH sensitive, and their electronic structure was studied with spectroscopic and computational methods.

Evaluation of tumor oxygenation by color duplex sonography: a new approach.

Objective: Description of a new noninvasive method for the evaluation of tissue oxygenation in head and neck cancer.

Study Design And Setting: Prospective nonrandomized controlled study in an academic medical center on 20 patients with neck metastases of head and neck cancer. Metastases were investigated using color duplex sonography and pO2 histography.

[Sonografic evaluation of oxygenation in head and neck cancer].

Background: Tumor oxygenation is an important aspect of radiosensitivity. The authors describe a new method for a non-invasive assessment of tumor oxygenation in head and neck cancer.

Patients And Methods: A group of 20 patients with neck metastases of squamous cell cancer of the head and neck region was surveyed.

The electronic portal imaging system Siemens Beamview Plus versus the conventional verification films CEA-TVS and DuPont COL-7. A critical appraisal of visual image quality.

Aim: The aim of this study was the validation of the visual image quality of electronic portal imaging devices (EPID) and conventional verification films from the point of view of the end-viewers of portal films, the radiotherapists.

Material And Methods: The verification image was represented in two different forms, viz. an electronic portal image employing Siemens Beamview Plus (on a computer monitor) and two different portal films using the conventional verification films CEA-TVS and DuPont CQL-7 (on a negatoscope).

An X-ray-based method for the determination of the contrast agent propagation in 3-D vessel structures.

A method for the determination of the contrast-agent propagation in vessel trees is presented. A standard three-dimensional (3-D) rotational angiography procedure is performed to reconstruct the morphology of the contrast-filled vessel tree in a 3-D volume. An additional fluoroscopy projection series acquired with a fixed projection angle delivers the temporal information of the bolus propagating.

Prognostic impact of total tumor volume and hemoglobin concentration on the outcome of patients with advanced head and neck cancer after concomitant boost radiochemotherapy.

Purpose: To identify prognostic clinical and treatment related factors for local control, distant metastasis-free survival, and survival by means of a multivariate analysis in patients with advanced squamous cell carcinoma of the head and neck after concomitant boost radiochemotherapy.

Patients And Methods: From 1992 to 1995, 68 patients with squamous cell cancer of the head and neck (93% stage IV disease) were treated with a simultaneous radiochemotherapy with Carboplatin using a concomitant boost technique. The total tumor volume (TTV) was quantitatively determined based on computed tomography scans in 56 patients.

[Possibilities of an open magnetic resonance scanner integration in therapy simulation and three-dimensional radiotherapy planning].

Purpose: A system for digital integration of an open MR scanner (0.23 T, Figure 1) in therapy simulation and 3D radiation treatment planning is described.

Method: MR images were acquired using the body coil and various positioning and immobilization aids.

Simulation of 3D-treatment plans in head and neck tumors aided by matching of digitally reconstructed radiographs (DRR) and on-line distortion corrected simulator images.

Background And Purpose: Simulation of 3D-treatment plans for head and neck malignancy is difficult due to complex anatomy. Therefore, CT-simulation and stereotactic techniques are becoming more common in the treatment preparation, overcoming the need for simulation. However, if simulation is still performed, it is an important step in the treatment preparation/execution chain, since simulation errors, if not detected immediately, can compromise the success of treatment.