| 1. |
- Ahnesjö, Anders
(författare)
-
Patient Dose Computation
- 2014
-
Ingår i: Comprehensive Biomedical Physics. - Amsterdam : Elsevier. - 9780444536327 - 9780444536334 ; , s. 235-247
-
Bokkapitel (refereegranskat)abstract
- Various dose calculation methods have been proposed to serve the needs in treatment planning of radiotherapy. Common to these are that they need a patient model to describe the interaction properties of the irradiated tissues, and a sufficiently accurate description of the incident radiation. This chapter starts with a brief review of the contexts in which patient dose calculations may serve, followed by a description of common methods for patient modelling and beam characterization. The focus is on external beam photon, but also partly covers particle beams like electrons and protons. The last section describes common approaches of varying complexity for dose calculations ranging from simple factor based models, more elaborate pencil and point kernel models, and finally summarizes some aspects of Monte Carlo and grid based methods.
|
|
| 2. |
- Komorowski, Jan
(författare)
-
Learning Rule-Based Models - The Rough Set Approach
- 2014
-
Ingår i: Comprehensive Biomedical Physics. - : Elsevier. - 9780444536327 - 9780444536334 ; , s. 19-39
-
Bokkapitel (refereegranskat)abstract
- Rough sets are a mathematically well-founded approach to induce minimal rules from examples represented in the form of decision systems. Rough sets have been successfully used to build classifiers in many domains including lifer sciences. This chapter introduces the concept of rough sets in a semi-formal way accessible to a non-expert reader. Rough sets have several advantages over other approaches such as, for instance, human legibility of the rule models by non-experts, and the ability to represent combinatorial models. Other advantages of rough sets include data reduction and uncertainty handling. With help of examples taken from a very broad spectrum of bioinformatics applications of rough sets ranging from functional genomics, to proteomics, to transcriptomics, to epigenetics, to cancer and HIV research, this introduction explains the basics of rough sets. It then continues to more advanced topics in building rough set classifiers. The focus is on the process of developing a rule-based model, its interpretation, and statistical significance, which discern this chapter from many a text on machine learning. Finally, rough sets are briefly compared to other learning approaches including some statistical approaches. The availability of ROSETTA allows learning how to use rough set modeling in practice. A discussion of relative advantages and disadvantages of rough sets ends this introduction.
|
|
| 3. |
- Nilsson, Bo, 1942-, et al.
(författare)
-
Interaction of ionizing radiation with matter
- 2014
-
Ingår i: Comprehensive biomedical physics. - : Elsevier. - 9780444536327 - 9780444536334 ; , s. 1-36
-
Bokkapitel (refereegranskat)abstract
- The aim of this chapter is to give an overview and try to show how the different interaction probabilities will influence the transport of ionizing radiation through matter. This knowledge is important in different aspects of medical applications of radiation. It has an impact in designing an optimal treatment gantry, in the choice of radiation quality, and of course when determining the absorbed dose distribution in the body. It is also important in diagnostic radiology when optimizing the image quality. Knowledge of the interaction of radiation with matter is also fundamental for understanding the biological effect of radiation and its variation with ionization density. The focus will not be on the basic physics and deriving the different cross sections but on the impact of these cross sections on imaging and therapy in medical physics applications.Ionizing radiation is normally divided into charged particles (previously called directly ionizing radiation) such as leptons, α-particles, protons and other light ions, and uncharged particles (previously called indirectly ionizing radiation) such as photons (x-rays or γ-rays) and neutrons. This chapter will concentrate on radiation qualities used in radiotherapy, and the main part will be dedicated to electrons and photons with energies up to around 50 MeV and light ions with energies up to 900 MeV per nucleon. The presentation is divided into two main sections, charged particles and photons.
|
|
| 4. |
- Dasu, Alexandru, et al.
(författare)
-
Long-term effects and secondary tumors
- 2014
-
Ingår i: Comprehensive biomedical physics. - Amsterdam : Elsevier. - 9780444536327 ; , s. 223-233, s. 223-233
-
Bokkapitel (refereegranskat)abstract
- The issue of secondary tumours as long-term effects of radiation therapy has gained increased importance as the life expectancy of cancer patients has increased due to improvements in detecting and treating their primary tumours. Current knowledge indicates that radiotherapy leads to a small but significant risk of inducing cancers which is often referred to as the price to pay for the effectiveness of this treatment modality. Nevertheless, the levels of incidence for the long-term effects of radiation therapy may be influenced by many factors that could be both treatment-related and patient-related and therefore proposals have been made to include risk estimations in the process of treatment optimisation. This chapter summarises the current knowledge concerning the induction of secondary cancers after radiotherapy and discusses their consequences for the therapeutic use of ionising radiation.
|
|
| 5. |
- Hertz, Hans M., et al.
(författare)
-
Electron-Impact Liquid-Metal-Jet Hard x-Ray Sources
- 2014
-
Ingår i: Comprehensive Biomedical Physics. - : Elsevier. - 9780444536327 ; , s. 91-109
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The power and brightness of electron-impact microfocus x-ray sources have long been limited by thermal damage in the target. This is a major constraint for a wide range of biomedical applications, from imaging to diffraction. Here, we describe the development of an x-ray microfocus source based on a new target concept, the liquid-metal jet (LMJ). The regenerative nature of this target allows for significantly higher e-beam power density than on conventional targets, resulting in this source showing promise for >. 100. × higher brightness than state-of-the-art sources. We first discuss the basic physics of the two important subsystems of the source, LMJ in vacuum and focused electron-beam systems, and then describe the properties of several versions of the source, from early prototypes to the first LMJ sources now reaching the market. Finally, we review some early applications of the source for biomedical imaging and diffraction.
|
|
| 6. |
- Lambrix, Patrick
(författare)
-
Semantic Web, Ontologies and Linked Data
- 2014
-
Ingår i: Comprehensive Biomedical Physics. - Amsterdam : Elsevier. - 9780444536334 ; , s. 67-76
-
Bokkapitel (refereegranskat)abstract
- Researchers in various areas in the life sciences use biomedical data sources and tools for their research. However, with the explosion of the amountof available data sources and tools, researchers also face the difficulties of finding and retrieving relevant information and tools as well as integratinginformation from different sources. The vision of the Semantic Web alleviates these difficulties. In this chapter, we introduce the Semantic Web anddiscuss steps that have been taken toward this vision. We discuss ontologies as a key technology as well as the recent development of Linked Data. Further, for each of these, we list issues for future research.
|
|
| 7. |
|
|
| 8. |
|
|
