Assessing Radiology and Radiation Therapy Needs for Cancer Care in Low-and-Middle-Income Countries: Insight From a Global Survey of Departmental and Institutional Leaders.

Purpose: The global cancer burden and mortality rates are increasing, with significant disparities in access to care in low- and middle-income countries (LMICs). This study aimed to identify radiology and radiation therapy needs in LMICs from the perspective of departmental and institutional leaders.

Methods And Materials: A survey was developed and conducted by the American Association of Physicists in Medicine Global Needs Assessment Committee and the American Association of Physicists in Medicine International Council.

The funding landscape for HIV in Asia and the Pacific.

Introduction: Despite recent and robust economic growth across the Asia-Pacific region, the majority of low- and middle-income countries in the region remain dependent on some donor support for HIV programmes. We describe the availability of bilateral and multilateral official development assistance (ODA) for HIV programmes in the region.

Methods: The donor countries considered in this analysis are Australia, Canada, Denmark, France, Germany, Netherlands, Norway, Sweden, the United Kingdom and the United States.

Defining health diplomacy: changing demands in the era of globalization.

Context: Accelerated globalization has produced obvious changes in diplomatic purposes and practices. Health issues have become increasingly preeminent in the evolving global diplomacy agenda. More leaders in academia and policy are thinking about how to structure and utilize diplomacy in pursuit of global health goals.

Radiation therapy of large intact breasts using a beam spoiler or photons with mixed energies.

Radiation treatment of large intact breasts with separations of more than 24 cm is typically performed using x-rays with energies of 10 MV and higher, to eliminate high-dose regions in tissue. The disadvantage of the higher energy beams is the reduced dose to superficial tissue in the buildup region. We evaluated 2 methods of avoiding this underdosage: (1) a beam spoiler: 1.

American Brachytherapy Society recommends no change for prostate permanent implant dose prescriptions using iodine-125 or palladium-103.

Purpose: In 2004, the American Association of Physicists in Medicine (AAPM) issued a report outlining recommended 125I and 103Pd datasets for consistency in calculating brachytherapy dose distributions. In 2005, to aid evaluating the clinical impact of implementing these datasets, the AAPM assessed the historical dependence of how prescribed doses differed from administered doses for 125I and 103Pd for permanent implantation of the prostate. Consequently, the American Brachytherapy Society (ABS) considered the nature of these changes towards issuing recommended dose prescriptions for 125I and 103Pd interstitial brachytherapy implants for monotherapy and standard boosts.

Measurement of the ultrasound backscatter signal from three seed types as a function of incidence angle: application to permanent prostate brachytherapy.

Purpose: To measure the relative ultrasound backscatter of different seed types as a function of seed orientation and to evaluate the corresponding images of these seeds.

Methods And Materials: Three seed types were evaluated: OncoSeed (standard), EchoSeed (corrugated), and RAPID Strand(RS). Ultrasound images for angles of incidence varying from 90 degrees (perpendicular) to 20 degrees at 5MHz and 7.

Dosimetric considerations for patients with HIP prostheses undergoing pelvic irradiation. Report of the AAPM Radiation Therapy Committee Task Group 63.

This document is the report of a task group of the Radiation Therapy Committee of the AAPM and has been prepared primarily to advise hospital physicists involved in external beam treatment of patients with pelvic malignancies who have high atomic number (Z) hip prostheses. The purpose of the report is to make the radiation oncology community aware of the problems arising from the presence of these devices in the radiation beam, to quantify the dose perturbations they cause, and, finally, to provide recommendations for treatment planning and delivery. Some of the data and recommendations are also applicable to patients having implanted high-Z prosthetic devices such as pins, humeral head replacements.

Development of a semi-automatic alignment tool for accelerated localization of the prostate.

Purpose: Delivering high dose to prostate with external beam radiation has been shown to improve local tumor control. However, it has to be carefully performed to avoid partial target miss and delivering excessive dose to surrounding normal tissues. One way to achieve safe dose escalation is to precisely localize prostate immediately before daily treatment.

Light and electron radiation fields' coincidence at extended distance.

Light field is routinely used for matching electron fields with adjacent photon fields and also positioning an ion chamber for cutout output measurements. At extended distance, however, the peripheral aspects of a radiation field are shifted with respect to their light shadow by up to 10 mm at SSD of 115 cm. This is mostly due to a difference in positions of light and virtual electron sources; however loss of the lateral scatter equilibrium, electron scatter in air, and partial transmission through cutout edges can also contribute to the effect.

Determination of effective electron source size using multislit and pinhole cameras.

Two independent methods have been utilized for determination of effective source sizes for 6, 12, and 20 MeV electron beams generated by a Varian 2100C linear accelerator. First, a multislit camera has been constructed using parallel aluminum plates and plastic strip spacers, similar to the beam-spot camera for the photon source imaging. Second, pinhole imaging was performed using a lead plate with a small hole on the central axis of the beam.

Electron wedges for radiation therapy.

Purpose: Brain tumors can be advantageously treated with electron over photon radiation, by exploiting the rapid fall-off in dose with depth. This advantage could be further enhanced by utilizing multiple electron beams. However, in some beam configurations, wedged dose profiles would be necessary for the dose uniformity.

Measuring dose distributions for enhanced dynamic wedges using a multichamber detector array.

This paper investigates measuring dose distributions for enhanced dynamic wedges (EDWs) using a commercial multichamber detector array. The technical aspects of using the chamber array, including chamber calibration, selection of measurement parameters, and use of the reference chamber, have been fully investigated. The measurement results from the chamber array were also confirmed by those from the single chamber and radiographic film measurements.

Dosimetric properties of a scanned beam microtron at low monitor unit settings: importance for conformal therapy.

The dosimetric stability, linearity, dose rate dependence, and flatness of both photon and electron beams have been evaluated for a racetrack microtron at low monitor unit settings. For photons, the variation in dosimetric output about the mean is < 0.4% at 100 monitor units (MU), < 1% at 10 MU, and < 4% at 2 MU.

Electron dose profile shaping by modulation of a scanning elementary beam.

The use of multiple high energy electron beams has been limited in the treatment of deep seated tumors. This is principally because of the rapid increase in the physical electron beam penumbra as a result of the rise in large angle scattering with depth in the patient. This decreases the transverse dose gradient between the target volume and sensitive dose limiting structures and diminishes the ability to conform electron isodose lines to the target volume.