Absorbed dose calorimetry.

This article reviews the development and summarizes the state-of-the-art in absorbed dose calorimetry for all the common clinical beam modalities covered in reference dosimetry codes of practice, as well as for small and nonstandard fields, and brachytherapy. It focuses primarily on work performed in the last ten years by national laboratories and research institutions and is not restricted to primary standard instruments. The most recent absorbed dose calorimetry review article was published over twenty years ago by Ross and Klassen (1996), and even then, its scope was limited to water calorimeters. Since the application of calorimetry to the measurement of radiation has a long and often overlooked history, a brief introduction into its origins is provided, along with a summary of some of the landmark research that have shaped the current landscape of absorbed dose calorimeters. Technical descriptions of water and graphite calorimetry are kept general, as these have been detailed extensively in relatively recent review articles (e.g., Seuntjens &Duane 2009, McEwen and DuSautoy 2009). The review categorizes calorimeters by the radiation type for which they are applied; from the widely established standards for Co-60 and high-energy x-rays, to the prototype calorimeters used in high-energy electrons and hadron therapy. In each case, focus is placed on the issues and constraints affecting dose measurement in that beam type, and the innovations developed to meet these requir...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research

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ConclusionsWe recommend the use of EBT3 films in routine X-ray based BI dosimetry checks. The presented method takes advantage of available radiotherapy equipment that can be efficiently used for EBT3 films calibration. The method is fast, reproducible and saves valuable medical physicist's time.
Source: Reports of Practical Oncology and Radiotherapy - Category: Cancer & Oncology Source Type: research
Conclusion: We derived radiosensitivity parameters for two CRC cell lines exposed to <sup>90</sup>Y, 6 MV x-rays, and 137Cs γ-rays irradiation. These radiobiological parameters are critical to understanding the dose response of CRC lesions and ultimately informs the efficacy of <sup>90</sup>Y SIRT relative to other radiation therapy modalities. PMID: 31117062 [PubMed - as supplied by publisher]
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research
The use of rectal brachytherapy is increasing. Two forms of rectal brachytherapy are available; contact brachytherapy using low energy X-Rays (CXB) and high dose rate brachytherapy (HDR-B). The use of a contact brachytherapy boost has been shown in medically inoperable patients to Result in a significantly lower rate of colostomy formation. In the UK approval has been granted by the National Institute of Clinical Excellence (NICE) for its use for primary rectal cancer control, particularly in elderly patients.
Source: Brachytherapy - Category: Cancer & Oncology Authors: Source Type: research
Erica S. Tarabadkar† and Michi M. Shinohara*† Division of Dermatology, University of Washington, Seattle, WA, United States Skin directed therapies (SDTs) serve important roles in the treatment of early stage cutaneous T-cell lymphoma (CTCL)/mycosis fungoides (MF), as well as managing symptoms and improving quality of life of all stages. There are now numerous options for topical therapies that demonstrate high response rates, particularly in early/limited MF. Phototherapy retains an important role in treating MF, with increasing data supporting efficacy and long-term safety of both UVB and PUVA as ...
Source: Frontiers in Oncology - Category: Cancer & Oncology Source Type: research
Authors: Wali LM, Helal AM, Darwesh RM, Attar MA Abstract BACKGROUND: Cervical cancer radiotherapy is usually administrated through 3-Dimensional Conformal Radiation Therapy (3DCRT) followed by a brachytherapy (BT) boost. PURPOSE: To investigate whether Volumetric Modulated Arc Therapy (VMAT) can replace High Dose Rate (HDR) intracavitary BT boost for patients undergoing cervical cancer radiotherapy. MATERIALS AND METHODS: Computed Tomography (CT) images for ten patients with tandem and ovoids were included in this study. Target volumes, rectum, bladder, sigmoid, small bowel and both femoral heads were deli...
Source: Journal of X-Ray Science and Technology - Category: Radiology Tags: J Xray Sci Technol Source Type: research
Electronic Brachytherapy (EBX), a technique that utilizes miniaturized X-Rays source, is gaining ground in radiotherapy treatment in presence of small superficial lesions. This work focuses on acceptance test, commissioning, clinical implementation and dosimetric features of the novel EBX system Esteya ® (Elekta AB, Stockholm, Sweden).
Source: Physica Medica: European Journal of Medical Physics - Category: General Medicine Authors: Source Type: research
Publication date: Available online 31 October 2018Source: Radiation Physics and ChemistryAuthor(s): Eslam Taha, Fathi Djouider, Essam BanoqitahAbstractThe use of silver nanoparticles as adjuvants in cancer radiation therapy is becoming progressively well acknowledged. Based on simulation methods, we report outcomes on dose enhancement for different silver concentrations implant and different beam energies, using GATE Monte-Carlo simulation. A digital phantom of the head was imported into GATE to provide accurate geometrical representation of the brain tissues. A 1-cm radius spherical tumor was placed at the center of the p...
Source: Radiation Physics and Chemistry - Category: Physics Source Type: research
Age-related macular degeneration (AMD) is the leading cause of blindness in aging adults and affects millions of patients in the U.S. and even more worldwide. Existing treatments of the most devastating neovascular form of AMD involve monthly injections into the eye(s) of patients, who typically are elderly. These injections are costly and burdensome, requiring periodic intraocular injections for drug delivery. Radiation has been used to treat AMD: 6 MV external-beam radiation irradiation, proton therapy, and most recently stereotactic x-rays and beta applicators.
Source: Brachytherapy - Category: Cancer & Oncology Authors: Source Type: research
BARD¿ BrachySource¿ Iodine125 radioactive seeds consist of a welded titanium capsule containing the I125 absorbed onto a nickel / copper-coated, gold-cored aluminum wire (reference Figure 1 below). The I125 has a half-life of 59.6 days and decays by electron capture with the emission of characteristic photons and Auger electrons. The principal photon emissions are 27.4 and 31 keV x-rays and 35.5 keV gamma. The titanium wall of the BrachySource¿ Seed Implants absorbs the electrons.
Source: Medical Device Recalls - Category: Medical Devices Source Type: alerts
Certain radiation responsive skin diseases, such as Kaposi ’s sarcoma (KS), mycosis fungoides (MF) and Sézary syndrome (SS), may develop symptoms on the upper or the lower half of the body. KS, in its epidemic form, is frequently present in patients with a prior infection of HIV-1 retrovirus [1–3]. Most common irradiation techniques for KS either invol ve schemes of 20 Gy in 5 fractions or 24 Gy in 12 fractions [4–7], producing similar responses and toxicities. For small areas of occurrence, treatment of the superficial targets can be performed with X-rays using VMAT techniques [1] or via brach...
Source: Physica Medica: European Journal of Medical Physics - Category: General Medicine Authors: Tags: Original paper Source Type: research
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