Investigations of peripheral dose for helical tomotherapy.

Purpose: Whenever treating a patient with percutaneous radiotherapy, a certain amount of dose is inevitably delivered to healthy tissue. This is mainly due to beam's entry and exit in the region of the target volume. In regions distant from the target volume, dose is delivered by leakage from the MLC and head scatter from the accelerator head and phantom scatter from the target volume (peripheral dose).

Clinical evaluation of a laser surface scanning system in 120 patients for improving daily setup accuracy in fractionated radiation therapy.

Purpose: To evaluate the clinical suitability of a specific optical surface imaging system to detect setup errors in fractionated radiation therapy.

Methods And Materials: The setup correction accuracy of a 3-dimensional laser imaging system was analyzed for 6 different tumor locations with 20 patients each. For each patient, the setup corrections of the megavoltage computed tomography (MVCT) images of a TomoTherapy unit (TomoTherapy, Madison, WI) were compared with those of the laser system for the first 10 fractions.

Comparison of two respiration monitoring systems for 4D imaging with a Siemens CT using a new dynamic breathing phantom.

Four-dimensional computed tomography (4D-CT) requires breathing information from the patient, and for this, several systems are available. Testing of these systems, under realistic conditions, requires a phantom with a moving target and an expandable outer contour. An anthropomorphic phantom was developed to simulate patient breathing as well as lung tumor motion.

CT-myelography for high-dose irradiation of spinal and paraspinal tumors with helical tomotherapy: revival of an old tool.

Background And Purpose: High-dose irradiation or reirradiation of spinal and paraspinal tumors is a challenge particularly in the presence of metal artifacts after surgery. Image-guided advanced intensity-modulated radiotherapy delivers high-dose radiation to the tumor sparing the spinal cord. Precise delineation of the spinal cord is necessary treating para- and intraspinal tumors with a sufficient dose.

Leakage of the Siemens 160 MLC multileaf collimator on a dual energy linear accelerator.

Multileaf collimators (MLCs) have been in clinical use for many years and meanwhile are commonly used to deliver intensity-modulated radiotherapy (IMRT) beams. For this purpose it is important to know their dosimetric properties precisely, one of them being inter- and intraleaf leakage. The Siemens 160 MLC features a single focus design with flat-sided and tilted leaves instead of tongue-and-groove.