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.

Imaging primary lung cancers in mice to study radiation biology.

Purpose: To image a genetically engineered mouse model of non-small-cell lung cancer with micro-computed tomography (micro-CT) to measure tumor response to radiation therapy.

Methods And Materials: The Cre-loxP system was used to generate primary lung cancers in mice with mutation in K-ras alone or in combination with p53 mutation. Mice were serially imaged by micro-CT, and tumor volumes were determined.

An effective preoperative three-dimensional radiotherapy target volume for extremity soft tissue sarcoma and the effect of margin width on local control.

Purpose: There is little information on the appropriate three-dimensional (3D) preoperative radiotherapy (XRT) volume for extremity soft-tissue sarcomas (STS). We retrospectively analyzed the pattern of local failure (LF) to help elucidate optimal field design.

Methods And Materials: We analyzed the 56 patients who underwent computed tomography-planned XRT for Stage I to III extremity STS between June 2000 and December 2006.

Inter- and intramouse heterogeneity of radiation response for a growing paired organ.

An intensive search for predictive markers of individual radiation response of apparently normal tissues in cancer patients is in progress at the genetic and epigenetic levels. However, the relative impact of variability at these levels is not clear. Experimental results obtained in inbred rodents, which have significantly reduced genetic heterogeneity relative to a population of human patients, may help to clarify this issue.

Radiotherapy treatment of early-stage prostate cancer with IMRT and protons: a treatment planning comparison.

Purpose: To compare intensity-modulated photon radiotherapy (IMRT) with three-dimensional conformal proton therapy (3D-CPT) for early-stage prostate cancer, and explore the potential utility of intensity-modulated proton therapy (IMPT).

Methods And Materials: Ten patients were planned with both 3D-CPT (two parallel-opposed lateral fields) and IMRT (seven equally spaced coplanar fields). Prescribed dose was 79.

Design of 4D treatment planning target volumes.

Purpose: When using non-patient-specific treatment planning margins, respiratory motion may lead to geometric miss of the target while unnecessarily irradiating normal tissue. Imaging different respiratory states of a patient allows patient-specific target design. We used four-dimensional computed tomography (4DCT) to characterize tumor motion and create treatment volumes in 10 patients with lung cancer.

Dosimetric comparison of proton and photon three-dimensional, conformal, external beam accelerated partial breast irradiation techniques.

Purpose: To compare the dosimetry of proton and photon-electron three-dimensional, conformal, external beam accelerated partial breast irradiation (3D-CPBI).

Methods And Materials: Twenty-four patients with fully excised, Stage I breast cancer treated with adjuvant proton 3D-CPBI had treatment plans generated using the mixed-modality, photon-electron 3D-CPBI technique. To facilitate dosimetric comparisons, planning target volumes (PTVs; lumpectomy site plus 1.

Dosimetric comparison of two different three-dimensional conformal external beam accelerated partial breast irradiation techniques.

Purpose: We compare the dosimetry of two techniques for three-dimensional, conformal, external beam, accelerated partial breast irradiation (3D-CPBI) in the supine position.

Methods And Materials: Sixteen patients with Stage I breast cancer had PBI treatment plans generated using the multiple, noncoplanar photon field technique and the three-field, mixed-modality technique. Planning target volumes (PTVs; lumpectomy site plus 1.

Clinical experience with a 3D surface patient setup system for alignment of partial-breast irradiation patients.

Purpose: To assess the utility of surface imaging on patient setup for accelerated partial-breast irradiation (APBI).

Methods And Material: A photogrammetry system was used in parallel to APBI setup by laser and portal imaging. Surface data were acquired after laser and port-film setup for 9 patients.

Initial dosimetric experience using simple three-dimensional conformal external-beam accelerated partial-breast irradiation.

Purpose: Several accelerated partial-breast irradiation (APBI) techniques are being investigated in patients with early-stage breast cancer. We present our initial experience using three-dimensional conformal radiation therapy (3D-CRT).

Methods And Materials: Sixty-one patients with tumors of 2 cm or less and negative axillary nodes were treated with 3D-CRT accelerated partial-breast irradiation (APBI) between August 2003 and March 2005.

A phantom evaluation of a stereo-vision surface imaging system for radiotherapy patient setup.

External beam irradiation requires precise positioning of the target relative to the treatment planning coordinate system. A three-dimensional (3D) surface imaging system for patient positioning has recently been installed in one of our linear accelerator (linac) rooms. The device utilizes close-range photogrammetry to generate a 3D model of the patient's surface.

Internal target volume determined with expansion margins beyond composite gross tumor volume in three-dimensional conformal radiotherapy for lung cancer.

Purpose: Gross tumor volume (GTV) of lung cancer defined by fast helical CT scan represents an image of moving tumor captured at a point in active respiratory movement. However, the method for defining internal margins beyond GTV to account for its expected physiologic movement and all variations in size and shape during the administration of radiation has not been established. The goal of this study was to determine the internal margins with expansion margins beyond individual GTVs defined with (1) fast scan at shallow free breathing, (2) breath-hold scans at the end of tidal volume inspiration and expiration, and (3) 4-s slow scan to approximate the composite GTV of all scans.