Medical physics is a branch of applied physics concerning the application of physics to medicine. It generally concerns physics as applied to medical imaging and radiotherapy, although a medical physicist may also work in many other areas of healthcare. A medical physics department may be based in either a hospital or a university and its work is likely to include research, technical development and clinical healthcare.

Medical imaging

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• Diagnostic radiology, including x-rays, fluoroscopy, mammography, Dual energy X-ray absorptiometry, angiography and Computed tomography
• Ultrasound, including intravascular ultrasound
• Non-ionising radiation (Lasers, Ultraviolet etc.)
• Nuclear medicine, including SPECT and positron emission tomography (PET)
• Magnetic resonance imaging (MRI), including functional magnetic resonance imaging (fMRI) and other methods for functional neuroimaging of the brain.
  • For example, nuclear magnetic resonance (often referred to as magnetic resonance imaging to avoid the common concerns about radiation), uses the phenomenon of nuclear resonance to image the human body.
• Magnetoencephalography
• Electrical impedance tomography
• Diffuse optical imaging
• Optical coherence tomography
• Terahertz radiation

Treatment of disease

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• Defibrillation
• High intensity focussed ultrasound, including lithotripsy
• Interventional radiology
• Non-ionising radiation Lasers, Ultraviolet etc. including photodynamic therapy and LASIK
• Nuclear medicine, including unsealed source radiotherapy
• Photomedicine, the use of light to treat and diagnose disease
• Radiotherapy
• Sealed source radiotherapy

More on [ Medical physics ]

Magnetic Resonance Materials in Physics, Biology and Medicine (Online First™)

The size of cytoplasmic lipid droplets varies between tumour cell lines of the nervous system: a 1H NMR spectroscopy study
Sat, 28 Apr 2012 05:59:18 -0000
Abstract Object  Cytoplasmic lipid droplets (LDs) are dynamic cellular organelles; their accumulation is associated with several cellular processes, such as cell proliferation, apoptosis and necrosis. 1H Nuclear Magnetic Resonance (NMR) spectroscopy detects resonances from lipids present in cytoplasmic (LDs); an understanding of the relationship between LD characteristics and NMR lipid signals is important. Materials and methods  In this study, five nervous system cancer cell lines were investigated. Nile red staining was used to measure the diameter of LDs. High-resolution magic angle spinning NMR (HR-MAS) was performed on harvested cell pellets to quantify the patterns of lipid signals. Results  LDs were present in all five cell lines with different morphology. An average LD diameter of approximately 0.2 μm was found in all cell types. Diameter of the largest LDs varied across the cell lines. The intensity of NMR lipid signals varied greatly between cell types, and a good correlation was found between total volume of LDs and the proton NMR lipid signal intensity at 0.9 and 1.3 ppm. Conclusion  The correlation implied that little NMR signal is detected from LDs of diameters less than approximately 0.34 μm, most likely due to restriction of rotational motion of the lipids. Content Type Journal ArticleCategory Research ArticlePages 1-7DOI 10.1007/s10334-012-0315-xAuthors Xiaoyan Pan, Cancer Sciences, University of Birmingham, Birmingham, UKMartin Wilson, Cancer Sciences, University of Birmingham, Birmingham, UKCarmel McConville, Cancer Sciences, University of Birmingham, Birmingham, UKTheodoros N. Arvanitis, Cancer Sciences, University of Birmingham, Birmingham, UKRisto A. Kauppinen, Electronic, Electrical and Computer Engineering, University of Birmingham, Birmingham, UKAndrew C. Peet, Cancer Sciences, University of Birmingham, Birmingham, UK Journal Magnetic Resonance Materials in Physics, Biology and MedicineOnline ISSN 1352-8661Print ISSN 0968-5243
Practical considerations for in vivo MRI with higher dimensional spatial encoding
Fri, 06 Apr 2012 15:46:08 -0000
Abstract Object  This work seeks to examine practical aspects of in vivo imaging when spatial encoding is performed with three or more encoding channels for a 2D image. Materials and methods  The recently developed 4-Dimensional Radial In/Out (4D-RIO) trajectory is compared in simulations to an alternative higher-order encoding scheme referred to as O-space imaging. Direct comparison of local k-space representations leads to the proposal of a modification to the O-space imaging trajectory based on a scheme of prephasing to improve the reconstructed image quality. Data were collected using a 4D-RIO acquisition in vivo in the human brain and several image reconstructions were compared, exploiting the property that the dense encoding matrix, after a 1D or 2D Fourier transform, can be approximated by a sparse matrix by discarding entries below a chosen magnitude. Results  The proposed prephasing scheme for the O-space trajectory shows a marked improvement in quality in the simulated image reconstruction. In experiments, 4D-RIO data acquired in vivo in the human brain can be reconstructed to a reasonable quality using only 5 % of the encoding matrix—massively reducing computer memory requirements for a practical reconstruction. Conclusion  Trajectory design and reconstruction techniques such as these may prove especially useful when extending generalized higher-order encoding methods to 3D images. Content Type Journal ArticleCategory Research ArticlePages 1-13DOI 10.1007/s10334-012-0314-yAuthors Daniel Gallichan, University Medical Center Freiburg, Freiburg, GermanyChris A. Cocosco, University Medical Center Freiburg, Freiburg, GermanyGerrit Schultz, University Medical Center Freiburg, Freiburg, GermanyHans Weber, University Medical Center Freiburg, Freiburg, GermanyAnna M. Welz, University Medical Center Freiburg, Freiburg, GermanyJürgen Hennig, University Medical Center Freiburg, Freiburg, GermanyMaxim Zaitsev, University Medical Center Freiburg, Freiburg, Germany Journal Magnetic Resonance Materials in Physics, Biology and MedicineOnline ISSN 1352-8661Print ISSN 0968-5243
Two eyes see more than one: double echo stereoscopic MRA for rapid 3D visualization of vascular structures
Thu, 05 Apr 2012 05:48:41 -0000
Abstract Object  A three-dimensional (3D) visualization of the target region during intravascular interventions in real-time is challenging since the acquisition of a time-consuming 3D dataset is required. In this work, a novel stereoscopic double echo sequence for achieving 3D depth perception by sampling only two oblique projection images is presented. Materials and methods  A double echo (DE) FLASH pulse sequence was developed to acquire continuously stereoscopic image pairs of the vascular target anatomy. Stereo image data were displayed on a stereoscopic 3D LCD monitor in real time after image reconstruction. Phantom experiments followed by a depth perception test were performed to assess the usability of the stereo image pairs for 3D visualization. In an animal experiment the sequence was tested in vivo and was compared with a slower interleaved (IL) sequence variant. Results  In the phantom experiments an SNR difference of 6 % between left and right image was found which did not influence the depth perception. The DE acquisition was superior to the IL sequence (SNRDE = 10.3, 2.3 images/s over SNRIL = 7.1, 1.7 images/s), and during contrast enhancement the abdominal arterial vasculature was clearly perceived as a 3D structure. Conclusion  A novel stereoscopic DE pulse sequence can be utilized for the fast 3D stereoscopic visualization of vascular structures in real-time. Content Type Journal ArticleCategory Research ArticlePages 1-8DOI 10.1007/s10334-012-0313-zAuthors Alexander Brunner, Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, GermanyFlorian Maier, Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, GermanyAxel Joachim Krafft, Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, GermanyWolfhard Semmler, Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, GermanyMichael Bock, Department of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany Journal Magnetic Resonance Materials in Physics, Biology and MedicineOnline ISSN 1352-8661Print ISSN 0968-5243
Effect of motion on the ADC quantification accuracy of whole-body DWIBS
Sat, 31 Mar 2012 05:46:24 -0000
Abstract Background and methods  Diffusion-weighted whole-body imaging with background body signal subtraction was introduced as a qualitative approach to detecting metastases in the body. A liver-mimicking phantom with embedded tumours that could be moved to replicate respiratory motion was developed to assess its ability to accurately quantify ADC values. Results  Mean tumour ADC values were unaltered by the motion; however, a significant (p < 0.05) increase in the spread of ADC values was measured, even for relatively large tumours. Conclusions  These findings may be of significance in cancer therapy monitoring where subtle changes in ADC histograms may reveal changes in tumour heterogeneity. Content Type Journal ArticleCategory Short CommunicationPages 1-4DOI 10.1007/s10334-012-0311-1Authors Alan J. Stone, Centre for Advanced Medical Imaging (CAMI), St. James’s Hospital/Trinity College, University of Dublin, Dublin, IrelandJacinta E. Browne, Medical Physics and Technology Group, School of Physics and FOCUS Institute, Dublin Institute of Technology, Dublin, IrelandBrian Lennon, Department of Medical Physics and Bioengineering, St. James’s Hospital, Dublin, IrelandJames F. Meaney, Centre for Advanced Medical Imaging (CAMI), St. James’s Hospital/Trinity College, University of Dublin, Dublin, IrelandAndrew J. Fagan, Centre for Advanced Medical Imaging (CAMI), St. James’s Hospital/Trinity College, University of Dublin, Dublin, Ireland Journal Magnetic Resonance Materials in Physics, Biology and MedicineOnline ISSN 1352-8661Print ISSN 0968-5243
Correlating brain blood oxygenation level dependent (BOLD) fractal dimension mapping with magnetic resonance spectroscopy (MRS) in Alzheimer’s disease
Fri, 23 Mar 2012 17:45:59 -0000
Abstract Objectives  To correlate temporal fractal structure of resting state blood oxygen level dependent (rsBOLD) functional magnetic resonance imaging (fMRI) with in vivo proton magnetic resonance spectroscopy (1H-MRS), in Alzheimer’s disease (AD) and healthy age-matched normal controls (NC). Materials and methods  High temporal resolution (4 Hz) rsBOLD signal and single voxel (left putamen) magnetic resonance spectroscopy data was acquired in 33 AD patients and 13 NC. The rsBOLD data was analyzed using two types of fractal dimension (FD) analysis based on relative dispersion and frequency power spectrum. Comparisons in FD were performed between AD and NC, and FD measures were correlated with 1H-MRS findings. Results  Temporal fractal analysis of rsBOLD, was able to differentiate AD from NC subjects (P = 0.03). Low FD correlated with markers of AD severity including decreased concentrations of N-acetyl aspartate (R = 0.44, P = 0.015) and increased myoinositol (mI) (R = −0.45, P = 0.012). Conclusion  Based on these results we suggest fractal analysis of rsBOLD could provide an early marker of AD. Content Type Journal ArticleCategory Research ArticlePages 1-10DOI 10.1007/s10334-012-0312-0Authors Mohammed A. Warsi, School of Biomedical Engineering, McMaster University, Hamilton, ON, CanadaWilliam Molloy, St. Peter’s Centre for Studies in Aging, Hamilton, ON, CanadaMichael D. Noseworthy, School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada Journal Magnetic Resonance Materials in Physics, Biology and MedicineOnline ISSN 1352-8661Print ISSN 0968-5243
Hepatic lipid composition differs between ob/ob and ob/+ control mice as determined by using in vivo localized proton magnetic resonance spectroscopy
Fri, 23 Mar 2012 05:44:33 -0000
Abstract Object  Hepatic lipid accumulation is associated with nonalcoholic fatty liver disease, and the metabolic syndrome constitutes an increasing medical problem. In vivo proton magnetic resonance spectroscopy (1H MRS) allows the assessment of hepatic lipid levels noninvasively and also yields information on the fat composition due to its high spectral resolution. Materials and methods  We applied 1H MRS at 9.4T to study lipid content and composition in eight leptin-deficient ob/ob mice as a model of obesity and in four lean ob/+ control mice at 24 weeks of age. PRESS sequence was used. For accurate estimation of signal intensity, differences in relaxation behavior of individual signals were accounted for each mouse individually. Also, in order to minimize spectral degrading due to motion artifacts, respiration gating was applied. Results  Significant differences between ob/ob and ob/+ control mice were found in both lipid content and composition. The mean chain length was found to be significantly longer in ob/ob mice with a higher fraction of monounsaturated lipids. Conclusion   1H MRS enables accurate assessment in hepatic lipids in mice, which is attractive for mechanistic studies of altered metabolism given the large number of genetically engineered mouse models available. Content Type Journal ArticleCategory Research ArticlePages 1-9DOI 10.1007/s10334-012-0310-2Authors Qiong Ye, Institute for Biomedical Engineering UZH/ETH, University and ETH Zurich, HIT E22.4, Wolfgang-Pauli-Strasse 27, 8093 Zurich, SwitzerlandCarsten Friedrich Danzer, Institute of Cell Biology, ETH Zurich, Zurich, SwitzerlandAlexander Fuchs, Institute for Biomedical Engineering UZH/ETH, University and ETH Zurich, 8093 Zurich, SwitzerlandChristian Wolfrum, Laboratory of Translational Nutritional Biology, ETH Zurich, Zurich, SwitzerlandMarkus Rudin, Institute for Biomedical Engineering UZH/ETH, University and ETH Zurich, HIT E22.4, Wolfgang-Pauli-Strasse 27, 8093 Zurich, Switzerland Journal Magnetic Resonance Materials in Physics, Biology and MedicineOnline ISSN 1352-8661Print ISSN 0968-5243

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