Comparison of perioperative and subacute postoperative complications between LDR and HDR monotherapy brachytherapy for prostate cancer.

Purpose: We aim to investigate perioperative and subacute postoperative complications in patients undergoing LDR or HDR monotherapy for prostate cancer. We hypothesize a low rate of complications, and a favorable toxicity profile in patients treated with HDR compared to LDR.

Materials And Methods: A prospectively collected institutional database was queried for patients treated with HDR or LDR prostate monotherapy between 1998 and 2021.

A dosimetric analysis of rectal hydrogel spacer use in patients with recurrent prostate cancer undergoing salvage high-dose-rate brachytherapy.

Purpose: We hypothesize rectal hydrogel spacer (RHS) improves rectal dosimetry in patients undergoing salvage high-dose-rate brachytherapy (HDR-BT) for intact, recurrent prostate cancer (PC).

Methods And Materials: A prospectively collected institutional database was queried for recurrent PC patients treated with salvage HDR-BT from September 2015 to November 2021. Patients were offered RHS beginning June 2019.

Evaluating suggested stricter gamma criteria for linac-based patient-specific delivery QA in the conventional and SBRT environments.

Purpose: To evaluate AAPM TG-218 recommended tolerances for IMRT QA for conventional and SBRT delivery.

Methods: QA analysis was repeated for 150 IMRT/VMAT patients with varying gamma criteria. True composite delivery was utilized, corrected for detector and output variation.

Monte Carlo Dose Calculation - A QA Method for SRT and SBRT Plans in Treating Multiple and Small Metastatic Lesions.

To provide accurate and fast 3-D dose verification for hypofractionated stereotactic radiotherapy (SRT/SBRT) of small and multi targets calculated with a Varian Eclipse treatment planning system (TPS) delivered on a Varian accelerator. Ten brain and lung hypofractionated SRT/SBRT linac-based and CyberKnife plans were generated by the Eclipse system for delivery on the accelerator with the Millenium-120 leaf multileaf collimator (MLC) and Multiplan for the CyberKnife machine. These clinical SRT/SBRT plans required accurate quality assurance measurements to obtain absolute point dose and 3-D dose distributions due to the low number of fractions and high fraction doses.

Employer and Co-worker Perspectives on Hiring and Working with People with Mental Health Conditions.

The purpose of this study was to understand perspectives towards hiring and working with people with mental health conditions (PMHC). Semi-structured interviews with 25 employers and 20 co-workers were carried out. Thematic analysis was used to analyse the data.

AAPM Task Group Report 272: Comprehensive acceptance testing and evaluation of fluoroscopy imaging systems.

Modern fluoroscopes used for image guidance have become quite complex. Adding to this complexity are the many regulatory and accreditation requirements that must be fulfilled during acceptance testing of a new unit. Further, some of these acceptance tests have pass/fail criteria, whereas others do not, making acceptance testing a subjective and time-consuming task.

Practical Clinical Implementation of the Special Physics Consultation Process in the Re-irradiation Environment.

Purpose: The purpose of this work is to present a practical, structured process allowing for consistent, safe radiation therapy delivery in the re-treatment environment.

Methods And Materials: A process for reirradiation is described with documentation in the form of a special physics consultation. Data acquisition associated with previous treatment is described from highest to lowest quality.

Time and frequency to observe fiducial markers in MLC-modulated fields during prostate IMRT/VMAT beam delivery.

Objective: This work investigates the time and frequency to observe fiducial markers in MLC-modulated fields during intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) beam delivery for real-time prostate localization.

Methods: Thirty seven prostate patients treated with IMRT or VMAT were included in this retrospective study. DRR images were generated for all MLC segments/control points using the TPS.

Positioning errors of metal localization devices with motion artifacts on kV and MV cone beam CT.

Objective: To investigate motion artifacts on kV CBCT and MV CBCT images with metal localization devices for image-guided radiation therapy.

Methods: The 8 μ pelvis CBCT template for the Siemens Artiste MVision and Pelvis template for the Varian IX on-board Exact Arms kV were used to acquire CBCT images in this study. Images from both CBCT modalities were compared in CNRs, metal landmark absolute positions, and image volume distortion on three different planes of view.

Evaluation of the combined use of two different respiratory monitoring systems for 4D CT simulation and gated treatment.

Purpose: Two different respiratory monitoring systems (Varian's Real-Time Position Management (RPM) System and Siemens' ANZAI belt Respiratory Gating System) are compared in the context of respiratory signals and 4D CT images that are accordingly reconstructed. This study aims to evaluate the feasibility of combined use of RPM and ANZAI systems for 4DCT simulation and gated radiotherapy treatment, respectively.

Methods: The RPM infrared reflecting marker and the ANZAI belt pressure sensor were both placed on the patient's abdomen during 4DCT scans.

When and how to treat an IMRT patient on a second accelerator without replanning?

When a linear accelerator is unavailable for treatment, a clinical decision is imminent regarding whether a patient should be treated on a linear accelerator other than the machine the patient was scheduled on, or whether treatment should be postponed until the original Linac becomes available. This work investigates the feasibility of switching patients to different accelerators for intensity-modulated radiation therapy (IMRT). We have performed Monte Carlo simulations of photon beams from different Linac models and vendors.

Evaluation of the cone beam CT for internal target volume localization in lung stereotactic radiotherapy in comparison with 4D MIP images.

Purpose: To investigate whether the three-dimensional cone-beam CT (CBCT) is clinically equivalent to the four-dimensional computed tomography (4DCT) maximum intensity projection (MIP) reconstructed images for internal target volume (ITV) localization in image-guided lung stereotactic radiotherapy.

Methods: A ball-shaped polystyrene phantom with built-in cube, sphere, and cone of known volumes was attached to a motor-driven platform, which simulates a sinusoidal movement with changeable motion amplitude and frequency. Target motion was simulated in the patient in a superior-inferior (S-I) direction with three motion periods and 2 cm peak-to-peak amplitudes.

Inhibitory effects of Rhenium-188-labeled Herceptin on prostate cancer cell growth: a possible radioimmunotherapy to prostate carcinoma.

Purpose: Herceptin is widely used in treating Her2-overexpressing breast cancer. However, the application of Herceptin in prostate cancer is still controversial. Our previous results have indicated the relevance of Her2 in the transition of the androgen requirement in prostate cancer cells.

Uncertainties in IMRT dosimetry.

Purpose: The purpose of this study is to investigate some characteristics of the beam delivery system and their effects on the dose distribution of intensity-modulated radiation therapy (IMRT) and the results of patient-specific IMRT quality assurance (QA). These characteristics include the accelerator source distribution and multileaf collimator (MLC) geometry.

Methods: Monte Carlo dose calculations based on intensity maps that were built from the actual deliverable IMRT leaf sequences with and without considering the characteristics of the beam delivery system were performed in this study using in-house Monte Carlo software.

Dosimetric investigation of high dose rate, gated IMRT.

Increasing the dose rate offers time saving for IMRT delivery but the dosimetric accuracy is a concern, especially in the case of treating a moving target. The objective of this work is to determine the effect of dose rate associated with organ motion and gated treatment using step-and-shoot IMRT delivery. Both measurements and analytical simulation on clinical plans are performed to study the dosimetric differences between high dose rate and low dose rate gated IMRT step-and-shoot delivery.