Peter Remeijer

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A cone beam computed tomography (CBCT) scanner integrated with a linear accelerator is a powerful tool for image guided radiotherapy. Respiratory motion, however, induces artifacts in CBCT, while the respiratory correlated procedures, developed to reduce motion artifacts in axial and helical CT are not suitable for such CBCT scanners. We have developed an(More)
PURPOSE To correctly evaluate realistic treatment plans in terms of absorbed dose to the clinical target volume (CTV), equivalent uniform dose (EUD), and tumor control probability (TCP) in the presence of execution (random) and preparation (systematic) geometric errors. MATERIALS AND METHODS The dose matrix is blurred with all execution errors to estimate(More)
In this review of current clinical practice of set-up error verification by means of portal imaging, we firstly define the various types of set-up errors using a consistent nomenclature. The different causes of set-up errors are then summarized. Next, the results of a large number of studies regarding patient set-up verification are presented for treatments(More)
PURPOSE To determine, in three-dimensions, the difference between prostate delineation in magnetic resonance (MR) and computer tomography (CT) images for radiotherapy treatment planning. PATIENTS AND METHODS Three radiation oncologists, considered experts in the field, outlined the prostate without seminal vesicles both on CT, and axial, coronal, and(More)
PURPOSE To evaluate the feasibility of adaptive radiotherapy (ART) in combination with a partial bladder irradiation. METHODS AND MATERIALS Twenty-one patients with solitary T1-T4 N0M0 bladder cancer were treated to the bladder tumor + 2 cm margin planning target volume (PTV(CONV)). During the first treatment week, five daily computed tomography (CT)(More)
PURPOSE To evaluate the feasibility, cardiac dose reduction, and the influence of the setup error on the delivered dose for fluoroscopy-guided deep inspiration breath hold (DIBH) irradiation using a cone-beam CT for irradiation of left-sided breast cancer patients. METHODS AND MATERIALS Nineteen patients treated according to the DIBH protocol were(More)
PURPOSE To quantify in three dimensions the geometric uncertainties of bladder irradiation (i.e., uncertainties in target delineation, organ motion, and patient setup). METHODS AND MATERIALS Pelvic CT images were obtained for 10 male bladder cancer patients. Apart from the initial planning CT scan, three follow-up scans were made for each of the patients.(More)
A technique was developed for bladder tumour demarcation with lipiodol injection through a flexible cystoscope. The technique proved to be simple and useful for image-guided radiotherapy in bladder cancer as well as a helpful aid in the tumour delineation process.
BACKGROUND AND PURPOSE To demonstrate the feasibility of back-projection portal dosimetry for accurate 3D dosimetric verification of volumetric-modulated arc therapy (VMAT), pre-treatment as well as in vivo. MATERIALS AND METHODS Several modifications to our existing approach were implemented to make the method applicable to VMAT: (i) gantry(More)
PURPOSE To quantify the differences in setup errors measured with the cone-beam computed tomography (CBCT) and electronic portal image devices (EPID) in breast cancer patients. METHODS AND MATERIALS Repeat CBCT scan were acquired for routine offline setup verification in 20 breast cancer patients. During the CBCT imaging fractions, EPID images of the(More)