Perspectives on program duration and research: A survey of graduates of a 3-year medical physics residency program.

Purpose: The goal of this manuscript is to evaluate strengths and weaknesses of a 3-year medical physics residency program with the first year dedicated to research and the remaining 2 years dedicated to clinical training.

Methods: An anonymous survey was distributed to graduates of a 3-year medical physics residency program with a dedicated year of research. Questions focused on several categories: (1) in retrospect, factors graduates considered at the time of application, (2) aspects of respondents' career and life after graduating from residency, (3) respondents' opinions on the residency duration, and (4) research productivity during residency.

Selecting the Most Relevant Mouse Strains for Evaluating Radiation-Induced Multiple Tissue Injury after Leg-Shielded Partial-Body Gamma Irradiation.

Animal studies are needed that best simulate a large-scale, inhomogeneous body exposure after a radiological or nuclear incident and that provides a platform for future development of medical countermeasures. A partial-body irradiation (PBI) model using 137Cs gamma rays with hind limb (tibia) shielding was developed and assessed for the sequalae of radiation injuries to gastrointestinal tract, bone marrow (BM) and lung and among different genetic mouse strains (C57BL/6J, C57L/J, CBA/J and FVB/NJ). In this case, a marginal level of BM shielding (∼2%) provided adequate protection against lethality from infection and hemorrhage and enabled escalation of radiation doses with evaluation of both acute and delayed radiation syndromes.

Ablative radiotherapy improves survival but does not cure autochthonous mouse models of prostate and colorectal cancer.

Background: Genetically engineered mouse models (GEMMs) of cancer are powerful tools to study mechanisms of disease progression and therapy response, yet little is known about how these models respond to multimodality therapy used in patients. Radiation therapy (RT) is frequently used to treat localized cancers with curative intent, delay progression of oligometastases, and palliate symptoms of metastatic disease.

Methods: Here we report the development, testing, and validation of a platform to immobilize and target tumors in mice with stereotactic ablative RT (SART).

Combined clinical and research training in medical physics in a multi-institutional setting: 13-year experience of Harvard Medical Physics Residency Program.

Purpose: This manuscript describes the structure, management and outcomes of a multi-institutional clinical and research medical physics residency program (Harvard Medical Physics Residency Program, or HMPRP) to provide potentially useful information to the centers considering a multi-institutional approach for their training programs.

Methods: Data from the program documents and public records was used to describe HMPRP and obtain statistics about participating faculty, enrolled residents, and graduates. Challenges associated with forming and managing a multi-institutional program and developed solutions for effective coordination between several clinical centers are described.

Preloaded 22-gauge fine-needle system facilitates placement of a higher number of fiducials for image-guided radiation therapy compared with traditional backloaded 19-gauge approach.

Background And Aims: Image-guided radiation therapy (IGRT) often relies on EUS-guided fiducial markers. Previously used manually backloaded fiducial needles have multiple potential limitations including safety and efficiency concerns. Our aim was to evaluate the efficacy, feasibility, and safety of EUS-guided placement of gold fiducials using a novel preloaded 22-gauge needle compared with a traditional, backloaded 19-gauge needle.

Radiation dose enhancement associated with contemporary dental materials.

Statement Of Problem: Electron backscatter radiation from dental materials can contribute to soft tissue injury in patients undergoing head and neck radiation therapy.

Purpose: The dose enhancement from the materials used for prosthodontic restoration of the dentition has not been well quantified. This study reports the magnitude of backscatter dose from the contemporary dental materials lithium disilicate and zirconia as compared with high-noble alloy and investigates the role of a spacer material in mitigating this effect.

4D cone beam CT-based dose assessment for SBRT lung cancer treatment.

The purpose of this research is to develop a 4DCBCT-based dose assessment method for calculating actual delivered dose for patients with significant respiratory motion or anatomical changes during the course of SBRT. To address the limitation of 4DCT-based dose assessment, we propose to calculate the delivered dose using time-varying ('fluoroscopic') 3D patient images generated from a 4DCBCT-based motion model. The method includes four steps: (1) before each treatment, 4DCBCT data is acquired with the patient in treatment position, based on which a patient-specific motion model is created using a principal components analysis algorithm.

3D delivered dose assessment using a 4DCT-based motion model.

Purpose: The purpose of this work is to develop a clinically feasible method of calculating actual delivered dose distributions for patients who have significant respiratory motion during the course of stereotactic body radiation therapy (SBRT).

Methods: A novel approach was proposed to calculate the actual delivered dose distribution for SBRT lung treatment. This approach can be specified in three steps.

Generation of fluoroscopic 3D images with a respiratory motion model based on an external surrogate signal.

Respiratory motion during radiotherapy can cause uncertainties in definition of the target volume and in estimation of the dose delivered to the target and healthy tissue. In this paper, we generate volumetric images of the internal patient anatomy during treatment using only the motion of a surrogate signal. Pre-treatment four-dimensional CT imaging is used to create a patient-specific model correlating internal respiratory motion with the trajectory of an external surrogate placed on the chest.