Heidi Th Lotz

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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 First, to quantify bladder-tumor motion in 3 dimensions during a 4-week to 5-week course of external radiotherapy. Second, to relate the motion to the tumor location on the bladder wall. Third, to extensively evaluate gross tumor volume (GTV) shape and volume changes during the course of the treatment. METHODS AND MATERIALS Multiple repeat(More)
The purpose of this study is to develop a model that quantifies in three dimensions changes in bladder shape due to changes in bladder and/or rectal volume. The new technique enables us to predict changes in bladder shape over a short period of time, based on known urinary inflow. Shortly prior to the treatment, the patient will be scanned using a cone beam(More)
PURPOSE To evaluate the impact of different tabletops with or without a knee support on the position of the rectum, prostate, and bulb of the penis; and to evaluate the effect of these patient-positioning devices on treatment planning. METHODS AND MATERIALS For 10 male volunteers, five MRI scans were made in four different positions: on a flat tabletop(More)
PURPOSE A biomechanical model was constructed to give insight into pelvic organ motion as a result of bladder filling changes. METHODS The authors used finite element (FE) modeling to simulate bladder wall deformation caused by urine inflow. For ten volunteers, a series of MRI scans of the pelvic area was recorded at regular intervals of 10 min over 1 h.(More)
BACKGROUND AND PURPOSE To study the impact of coronal and sagittal views (CSV) on the gross tumor volume (GTV) delineation on CT and matched PET/CT scans in non-small cell lung cancer. MATERIAL AND METHODS GTV delineations were performed by 11 experienced radiation oncologists on CT and PET/CT in 22 patients. Two tumor groups were defined: Group I:(More)
In 2010, the NCS (Netherlands Commission on Radiation Dosimetry) installed a subcommittee to develop guidelines for quality assurance and control for volumetric modulated arc therapy (VMAT) treatments. The report (published in 2015) has been written by Dutch medical physicists and has therefore, inevitably, a Dutch focus. This paper is a condensed version(More)
The feasibility of high precision radiotherapy to the bladder region is limited by bladder motion and volume changes. In the near future, we plan to begin treatment delivery of bladder cancer patients with the acquisition of a cone beam CT image on which the complete bladder will be semi-automatically localized. Subsequently, a bladder shape model that was(More)
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