Physician review of image registration and normal structure delineation.

Introduction: Image registration and delineation of organs at risk (OARs) are key components of three-dimensional conformal (3DCRT) and intensity-modulated radiotherapy (IMRT) treatment planning. This study hypothesized that image registration and OAR delineation are often performed by medical physicists and/or dosimetrists and are not routinely reviewed by treating physicians.

Methods: An anonymous, internet-based survey of medical physicists and dosimetrists was distributed via the MEDPHYS and MEDDOS listserv groups.

A feasibility study of 2-mm bolus for postmastectomy radiation therapy.

Purpose: The purpose of this study was to prospectively evaluate the use of daily 2-mm bolus in patients undergoing postmastectomy radiation without reconstruction using optically stimulated luminescence dosimetry and weekly assessment of skin toxicity.

Methods And Materials: We prospectively collected data from the first 49 women treated with a daily 2-mm Superflab bolus during their postmastectomy radiation therapy from 2013 to 2016 at The University of Chicago Comprehensive Cancer Center at Silver Cross. Within the first 3 days of starting radiation therapy, we measured the surface dose in vivo at 5 anatomical locations under the 2-mm bolus on the chest wall.

A Prostate Fossa Contouring Instructional Module: Implementation and Evaluation.

Purpose/objective: Radiation oncology trainees frequently learn to contour through clinical experience and lectures. A hands-on contouring module was developed to teach delineation of the postoperative prostate clinical target volume (CTV) and improve contouring accuracy.

Methods: Medical students independently contoured a prostate fossa CTV before and after receiving educational materials and live instruction detailing the RTOG approach to contouring this CTV.

Image-guided radiation therapy for prostate cancer: A computed tomography-based assessment of fiducial marker migration between placement and 7 days.

Purpose: This study was conducted to determine whether clinically significant fiducial marker migration occurs immediately after prostatic implantation.

Methods And Materials: One hundred patients with transperineal (n = 39) or transrectal (n = 61) placement of 3 gold fiducial markers underwent computed tomography scans on day 0 (after placement) and day 7 (at radiation planning). Each marker was marked as a point of interest in a treatment planning system.

Improvements in dose accuracy delivered with static-MLC IMRT on an integrated linear accelerator control system.

Purpose: Dose accuracy has been shown to vary with dose per segment and dose rate when delivered with static multileaf collimator (SMLC) intensity modulated radiation therapy (IMRT) by Varian C-series MLC controllers. The authors investigated the impact of monitor units (MUs) per segment and dose rate on the dose delivery accuracy of SMLC-IMRT fields on a Varian TrueBeam linear accelerator (LINAC), which delivers dose and manages motion of all components using a single integrated controller.

Methods: An SMLC sequence was created consisting of ten identical 10 × 10 cm(2) segments with identical MUs.

Intra- and interfractional variations for prone breast irradiation: an indication for image-guided radiotherapy.

Purpose: Intra- and interfractional errors for breast cancer patients undergoing breast irradiation in the prone position were analyzed.

Methods And Materials: To assess intrafractional error resulting from respiratory motion, four-dimensional computed tomography scans were acquired for 3 prone and 3 supine patients, and the respiratory motion was compared for the two positions. To assess the interfractional error caused by daily set-up variations, daily electronic portal images of one of the treatment beams were taken for 15 prone-positioned patients.

Technical and dosimetric aspects of respiratory gating using a pressure-sensor motion monitoring system.

This work introduces a gating technique that uses 4DCT to determine gating parameters and to plan gated treatment, and employs a Siemens linear accelerator to deliver the gated treatment. Because of technology incompatibility, the 4DCT scanner (LightSpeed, GE) and the Siemens accelerator require two different motion-monitoring systems. The motion monitoring system (AZ-773V, Anzai Med.