Evaluation of a head-repositioner and Z-plate system for improved accuracy of dose delivery.

Radiation therapy requires accurate dose delivery to targets often identifiable only on computed tomography (CT) images. Translation between the isocenter localized on CT and laser setup for radiation treatment, and interfractional head repositioning are frequent sources of positioning error. The objective was to design a simple, accurate apparatus to eliminate these sources of error.

A block design for split-field tests of accelerator alignment.

We present a block design that facilitates split-field tests, a technique frequently employed to assess several potential misalignments in linear accelerators. Two tests are possible with this device using: (1) opposed collimator angles and (2) opposed gantry angles. The first test is sensitive to jaw symmetry only.

Development of a semi-automatic alignment tool for accelerated localization of the prostate.

Purpose: Delivering high dose to prostate with external beam radiation has been shown to improve local tumor control. However, it has to be carefully performed to avoid partial target miss and delivering excessive dose to surrounding normal tissues. One way to achieve safe dose escalation is to precisely localize prostate immediately before daily treatment.

CT image-guided intensity-modulated therapy for paraspinal tumors using stereotactic immobilization.

Purpose: To design and implement a noninvasive stereotactic immobilization technique with daily CT image-guided positioning to treat patients with paraspinal lesions accurately and to quantify the systematic and random patient setup errors occurring with this method.

Methods And Materials: A stereotactic body frame (SBF) was developed for "rigid" immobilization of paraspinal patients. The inherent accuracy of this system for stereotactic CT-guided treatment was evaluated with phantom studies.