Preclinical study investigating the potential of low-dose-rate brachytherapy with P stents for the prevention of restenosis of paranasal neo-ostia.

Purpose: Ostial restenosis is a common cause of failures in paranasal sinus surgery. The aim of the current study was to investigate the use of low-dose-rate brachytherapy to prevent neo-ostial restenosis in an animal model.

Methods And Materials: In 14 rabbits, maxillary neo-ostia were created and measured.

Measurements to predict the time of target replacement of a helical tomotherapy.

Intensity-modulated radiation therapy (IMRT) requires more beam-on time than normal open field treatment. Consequently, the machines wear out and need more spare parts. A helical tomotherapy treatment unit needs a periodical tungsten target replacement, which is a time consuming event.

Scanning irradiation device for mice in vivo with pulsed and continuous proton beams.

A technical set-up for irradiation of subcutaneous tumours in mice with nanosecond-pulsed proton beams or continuous proton beams is described and was successfully used in a first experiment to explore future potential of laser-driven particle beams, which are pulsed due to the acceleration process, for radiation therapy. The chosen concept uses a microbeam approach. By focusing the beam to approximately 100 × 100 μm(2), the necessary fluence of 10(9) protons per cm(2) to deliver a dose of 20 Gy with one-nanosecond shot in the Bragg peak of 23 MeV protons is achieved.

Evaluation of the SUV values calculation and 4D PET integration in the radiotherapy treatment planning system.

Background And Purpose: To evaluate the SUV calculation and integration of the gated (4D) PET in the iPlan 4.0 treatment planning software (BrainLAB).

Materials And Methods: Phantom and patient data for different tracers were used.

A planning comparison of dynamic IMRT for different collimator leaf thicknesses with helical tomotherapy and RapidArc for prostate and head and neck tumors.

Purpose: A comparative analysis of the three most advanced intensity-modulated radiotherapy (IMRT) techniques currently commercially available was performed. Treatment plans made in rotational techniques (helical tomotherapy [HT] and RapidArc) were compared with sliding-window IMRT (dIMRT) on a conventional linear accelerator using different leaf thicknesses (2.5 mm, 5 mm, and 10 mm).

A new modification of combining vacuum therapy and brachytherapy in large subfascial soft -tissue sarcomas of the extremities.

Purpose: To present a modification of a technique combining the advantages of brachytherapy for local radiation treatment and vacuum therapy for wound conditioning after resection of subfascial soft-tissue sarcomas (STS) of the extremities.

Patients And Methods: Between January and May 2008, four patients with large (> 10 cm) subfascial STS of the thigh underwent marginal tumor excision followed by early postoperative HDR (high-dose-rate) brachytherapy (iridium-192) and vacuum therapy as part of their interdisciplinary treatment. The sponge of the vacuum system was used to stabilize brachytherapy applicators in parallel positions and to allow for a maximal wound contraction in the early postoperative phase, thus preventing seroma and deterioration of local dose distribution as optimized in computed tomography-(CT-)based three-dimensional conformal treatment planning.

A method for improved verification of entire IMRT plans by film dosimetry.

Background And Purpose: : In one entire intensity-modulated radiation therapy (IMRT) plan, beams coming from different directions have different penetration depths in the phantom. Therefore, verifying an entire IMRT plan with a calibration curve for a single depth is error-prone. The aim of this study is to improve the quality of the dose verification of entire IMRT plans with film dosimetry.

The Munich Fission Neutron Therapy Facility MEDAPP at the research reactor FRM II.

Purpose: At the new research reactor FRM II of the Technical University of Munich (TUM), the facility for Medical Applications (MEDAPP) was installed where fast neutrons are available as a beam for medical use.

Material And Methods: Thermal neutrons induce fission in a pair of uranium converter plates and generate fast neutrons which are guided to the patient by a beam tube. The maximum opening of the multi leaf collimator (MLC) is 30x20 cm2 WxH.

Influence of different treatment techniques on radiation dose to the LAD coronary artery.

Background: The purpose of this proof-of-principle study was to test the ability of an intensity-modulated radiotherapy (IMRT) technique to reduce the radiation dose to the heart plus the left ventricle and a coronary artery. Radiation-induced heart disease might be a serious complication in long-term cancer survivors.

Methods: Planning CT scans from 6 female patients were available.

Comparison of three different mediastinal radiotherapy techniques in female patients: Impact on heart sparing and dose to the breasts.

Background And Purpose: To study different radiotherapy techniques for female patients with mediastinal target volumes. Especially in highly curable diseases such as lymphoma, long-term survivors might develop late cardiac damage and radiation-induced second cancer.

Patients And Methods: Planning CT scans were obtained in eight cases.

Dose to the intracranial arteries in stereotactic and intensity-modulated radiotherapy for skull base tumors.

Purpose: To examine retrospectively the maximum dose to the large skull base/intracranial arteries in fractionated stereotactic radiotherapy (FSRT) and intensity-modulated radiotherapy (IMRT), because of the potential risk of perfusion disturbances.

Methods And Materials: Overall, 56 patients with tumors adjacent to at least one major artery were analyzed. Our strategy was to perform FSRT with these criteria: 1.

Validation of a method for automatic image fusion (BrainLAB System) of CT data and 11C-methionine-PET data for stereotactic radiotherapy using a LINAC: first clinical experience.

Purpose: (a) To implement a fully automatic method to integrate (11)C-methionine positron emission tomography (MET-PET) data into stereotactic radiation treatment planning using the commercially available BrainLAB System, by means of CT/MET-PET image fusion. (b) To validate the fully automatic CT/MET-PET image fusion technique with respect to accuracy and robustness. (c) To give a short glance at the clinical consequences for patients with brain tumors.

[Design of an inverse planning system for radiotherapy using linear optimization].

Our approach shows that inverse planning for intensity-modulated beams in radiotherapy can be solved efficiently by the mathematical method of linear optimization. The completeness property of this method guarantees that calculated treatment plans fulfill the dose constraints given by the oncologist. Techniques developed by our group can also avoid the possible infeasibility caused by a physically impossible dose distribution.