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Basics of Radiation Interactions in Matter
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
where is the mass density of matter. A complete quantum mechanical expression is provided by the Bethe–Bloch formula:
Reference Dose Determination under Reference Conditions
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
can be expressed in terms of the volume of the air cavity, V, the air mass density, r, and the measured charge, Q:
Mediastinal Liposarcoma after Remote History of Radiation as an Infant
Published in Wickii T. Vigneswaran, Thoracic Surgery, 2019
James L. Lubawski, Wickii T. Vigneswaran
A 65-year-old man with no significant past medical history presented to his primary care physician with a three-month history of progressively worsening cough and wheezing. This was worse when he would lie flat. He saw his primary care physician who ordered a chest X-ray, which showed a large, perihilar soft tissue mass. The chest X-ray was then followed by a computed tomography (CT) scan of the chest with contrast, which showed a large anterior mediastinal mass measuring at least 21 cm at its greatest dimension (Figure 18.1). The mass density was predominantly of fat. A core-needle biopsy showed a well-differentiated liposarcoma, and he was referred for surgical resection. An in-depth history done on surgical consultation revealed that the patient had undergone radiation therapy of the chest as an infant. At that time, it was believed that he had an “enlarged thymus.” He underwent several radiation treatments at six months of age. No records exist of how much radiation was given. The patient was otherwise healthy, other than symptoms of allergic rhinitis.
A unified framework of cell population dynamics and mechanical stimulus using a discrete approach in bone remodelling
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Diego Quexada, Salah Ramtani, Olfa Trabelsi, Kalenia Marquez, Dorian Luis Linero Segrera, Carlos Duque-Daza, Diego Alexander Garzón Alvarado
Among the classical literature regarding the biochemical studies of bone remodelling, the one by (Komarova et al. 2003), models the dynamic behavior of osteoblast and osteoclast and its influence in bone mass density (BMD) at the basic multicellular unit in accordance to histomorphometry data of bone sections (Parfitt 1994b). In this work different paracrine and autocrine regulators are modelled as will be seen later, mainly TGF- β, RANKL, among others, that are important in treatments of different pathologies such as Paget’s disease and osteoporosis. Furthermore, the response in the BMU presents an oscillatory behavior similar to that found clinical literature. The model is composed by three nonlinear differential equations that relate the population of osteoblasts (z), with different parameters that model the paracrine and autocrine regulators Eqs. (1) and (2). The bone mass density is presented as being 100% in the steady state which is in average 0.98 g/cm2 in young adults (Key 2020) for the femoral head.
Using MRI to measure position and anatomy changes and assess their impact on the accuracy of hyperthermia treatment planning for cervical cancer
Published in International Journal of Hyperthermia, 2023
Iva VilasBoas-Ribeiro, Martine Franckena, Gerard C. van Rhoon, Juan A. Hernández-Tamames, Margarethus M. Paulides
The energy absorbed in each tissue was described by the SAR, which corresponds to the rate at which EM energy is absorbed per unit of mass of tissue: 3) is the mass density and 32]. In this process, cubic filtered (cf)-SAR distribution was optimized, which aims at maximizing the Target-Hotspot-Quotient (THQ) [19,45,46], which is expressed as:
Colon-specific tablets containing 5-fluorouracil microsponges for colon cancer targeting
Published in Drug Development and Industrial Pharmacy, 2020
Mahmoud H. Othman, Gamal M. Zayed, Usama F. Ali, Ahmed A. H. Abdellatif
The bulk density and tapped density (gm/cm3) of the prepared powder mixture were determined using a graduated cylinder [30]. A correctly weighted sum of the powder (W), the graduated cylinder was carefully poured into, and the volume (V0) was calculated. The graduated cylinders were then shut down with a lid and placed in the density control unit. The density unit for 100 tabs has been mounted, and volume (Vf) was calculated. The mass density, tapped density, and formulae were calculated using the follwoing equation: