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  1. Article: Modelling the distribution of laser light in port-wine stains with the Monte Carlo method.

    Smithies, D J / Butler, P H

    Physics in medicine and biology

    1995  Volume 40, Issue 5, Page(s) 701–731

    Abstract: Using the Monte Carlo method, we have calculated the distribution of absorbed light in skin during the laser treatment of port-wine stains. Our model includes the effect that the blood capillaries and epidermis have on the propagation of light through ... ...

    Abstract Using the Monte Carlo method, we have calculated the distribution of absorbed light in skin during the laser treatment of port-wine stains. Our model includes the effect that the blood capillaries and epidermis have on the propagation of light through skin. It is more complete than those used by previous workers. In this paper, we change the number of scattering dimensions, the spot diameter, and the capillary separation and diameter, and we use the wavelengths 577 nm and 585 nm. One-dimensional scattering calculations are misleading but two-dimensional results suffice for large spot diameters. The model shows that changing the position or diameter of the capillaries has a larger effect on the distribution of absorbed light in the skin than changing the wavelength of the laser beam from 577 nm to 585 nm. Changing the wavelength does increase absorption in the deeper capillaries, but this is not significant. From our results, we discuss the optimal treatment of port-wine stains.
    MeSH term(s) Animals ; Biophysical Phenomena ; Biophysics ; Capillaries/radiation effects ; Hamartoma/surgery ; Humans ; Laser Coagulation ; Lasers ; Light ; Models, Biological ; Monte Carlo Method ; Scattering, Radiation ; Skin/blood supply ; Skin/radiation effects ; Skin Diseases/surgery ; Software
    Language English
    Publishing date 1995-05
    Publishing country England
    Document type Journal Article
    ZDB-ID 208857-5
    ISSN 1361-6560 ; 0031-9155
    ISSN (online) 1361-6560
    ISSN 0031-9155
    DOI 10.1088/0031-9155/40/5/001
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Brain function and personality in normal males: a SPECT study using statistical parametric mapping.

    Turner, R M / Hudson, I L / Butler, P H / Joyce, P R

    NeuroImage

    2003  Volume 19, Issue 3, Page(s) 1145–1162

    Abstract: Understanding the differences between individuals' personality types at a functional brain level is now possible due to recent developments in both functional brain imaging and personality models. The psychobiological model for temperament and character ... ...

    Abstract Understanding the differences between individuals' personality types at a functional brain level is now possible due to recent developments in both functional brain imaging and personality models. The psychobiological model for temperament and character offers one approach to exploring personality. This study uses SPECT imaging to investigate brain function in relationship to the personality traits in the Temperament and Character Index. A general linear model approach was implemented at a voxel-by-voxel level, using quartile groupings for the personality predictors. t contrasts were used to investigate significant clusters of activation or deactivation. The results show a number of significant relationships between personality traits and regional cerebral blood flow, which show distinct nonlinear trends. All seven of the Cloninger personality traits were significantly related to regional cerebral blood flow. The results suggest that differences in brain function in some regions may reflect differences in personality traits.
    MeSH term(s) Adult ; Algorithms ; Brain/diagnostic imaging ; Brain/physiology ; Brain Mapping ; Cerebrovascular Circulation ; Cluster Analysis ; Cooperative Behavior ; Exploratory Behavior/physiology ; Functional Laterality/physiology ; Harm Reduction/physiology ; Humans ; Image Processing, Computer-Assisted ; Male ; Personality/physiology ; Personality Tests ; Reference Values ; Reward ; Tomography, Emission-Computed, Single-Photon
    Language English
    Publishing date 2003-07-23
    Publishing country United States
    Document type Clinical Trial ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1147767-2
    ISSN 1095-9572 ; 1053-8119
    ISSN (online) 1095-9572
    ISSN 1053-8119
    DOI 10.1016/s1053-8119(03)00171-x
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Spectroscopic biomedical imaging with the Medipix2 detector.

    Melzer, T R / Cook, N J / Butler, A P / Watts, R / Anderson, N / Tipples, R / Butler, P H

    Australasian physical & engineering sciences in medicine

    2009  Volume 31, Issue 4, Page(s) 300–306

    Abstract: This study confirms that the Medipix2 x-ray detector enables spectroscopic bio-medical plain radiography. We show that the detector has the potential to provide new, useful information beyond the limited spectroscopic information of modem dual-energy ... ...

    Abstract This study confirms that the Medipix2 x-ray detector enables spectroscopic bio-medical plain radiography. We show that the detector has the potential to provide new, useful information beyond the limited spectroscopic information of modem dual-energy computed tomography (CT) scanners. Full spectroscopic 3D-imaging is likely to be the next major technological advance in computed tomography, moving the modality towards molecular imaging applications. This paper focuses on the enabling technology which allows spectroscopic data collection and why this information is useful. In this preliminary study we acquired the first spectroscopic images of human tissue and other biological samples obtained using the Medipix2 detector. The images presented here include the clear resolution of the 1.4mm long distal phalanx of a 20-week-old miscarried foetus, showing clear energy-dependent variations. The opportunities for further research using the forthcoming Medipix3 detector are discussed and a prototype spectroscopic CT scanner (MARS, Medipix All Resolution System) is briefly described.
    MeSH term(s) Computer-Aided Design ; Equipment Design ; Equipment Failure Analysis ; Radiographic Image Enhancement/instrumentation ; Reproducibility of Results ; Sensitivity and Specificity ; Spectrometry, X-Ray Emission/instrumentation ; Tomography, X-Ray Computed/instrumentation ; Transducers
    Language English
    Publishing date 2009-01-20
    Publishing country Netherlands
    Document type Evaluation Studies ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 46226-3
    ISSN 1879-5447 ; 0158-9938
    ISSN (online) 1879-5447
    ISSN 0158-9938
    DOI 10.1007/bf03178599
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Spectral CT of carotid atherosclerotic plaque: comparison with histology.

    Zainon, R / Ronaldson, J P / Janmale, T / Scott, N J / Buckenham, T M / Butler, A P H / Butler, P H / Doesburg, R M / Gieseg, S P / Roake, J A / Anderson, N G

    European radiology

    2012  Volume 22, Issue 12, Page(s) 2581–2588

    Abstract: Objective: To distinguish components of vulnerable atherosclerotic plaque by imaging their energy response using spectral CT and comparing images with histology.: Methods: After spectroscopic calibration using phantoms of plaque surrogates, excised ... ...

    Abstract Objective: To distinguish components of vulnerable atherosclerotic plaque by imaging their energy response using spectral CT and comparing images with histology.
    Methods: After spectroscopic calibration using phantoms of plaque surrogates, excised human carotid atherosclerotic plaques were imaged using MARS CT using a photon-processing detector with a silicon sensor layer and microfocus X-ray tube (50 kVp, 0.5 mA) at 38-μm voxel size. The plaques were imaged, sectioned and re-imaged using four threshold energies: 10, 16, 22 and 28 keV; then sequentially stained with modified Von Kossa, Perl's Prussian blue and Oil-Red O, and photographed. Relative Hounsfield units across the energies were entered into a linear algebraic material decomposition model to identify the unknown plaque components.
    Results: Lipid, calcium, iron and water-like components of plaque have distinguishable energy responses to X-ray, visible on spectral CT images. CT images of the plaque surface correlated very well with histological photographs. Calcium deposits (>1,000 μm) in plaque are larger than iron deposits (<100 μm), but could not be distinguished from each other within the same voxel using the energy range available.
    Conclusions: Spectral CT displays energy information in image form at high spatial resolution, enhancing the intrinsic contrast of lipid, calcium and iron within atheroma.
    Key points: Spectral computed tomography offers new insights into tissue characterisation. Components of vulnerable atherosclerotic plaque are spectrally distinct with intrinsic contrast. Spectral CT of excised atherosclerotic plaques can display iron, calcium and lipid. Calcium deposits are larger than iron deposits in atheroma. Spectral CT may help in the non-invasive detection of vulnerable plaques.
    MeSH term(s) Calcium/metabolism ; Carotid Artery Diseases/diagnostic imaging ; Carotid Artery Diseases/metabolism ; Carotid Artery Diseases/pathology ; Contrast Media ; Humans ; In Vitro Techniques ; Iohexol/analogs & derivatives ; Iron/metabolism ; Lipid Metabolism ; Phantoms, Imaging ; Plaque, Atherosclerotic/diagnostic imaging ; Plaque, Atherosclerotic/metabolism ; Plaque, Atherosclerotic/pathology ; Radiographic Image Interpretation, Computer-Assisted ; Staining and Labeling ; Tomography, X-Ray Computed/methods
    Chemical Substances Contrast Media ; Iohexol (4419T9MX03) ; iopromide (712BAC33MZ) ; Iron (E1UOL152H7) ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 2012-07-04
    Publishing country Germany
    Document type Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1085366-2
    ISSN 1432-1084 ; 0938-7994 ; 1613-3749
    ISSN (online) 1432-1084
    ISSN 0938-7994 ; 1613-3749
    DOI 10.1007/s00330-012-2538-7
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: The blanching process due to copper vapour laser treatment of port-wine stains.

    Mehrtens, N W / Smithies, D J / Butler, P H / Walker, E P

    Physics in medicine and biology

    1997  Volume 42, Issue 6, Page(s) 997–1007

    Abstract: We describe the causes and speed of transient blanching during copper vapour laser treatment of port-wine stains. Five watts of yellow (578 nm) light from a copper vapour laser was scanned over the lesion using a computer controlled scanning system. The ... ...

    Abstract We describe the causes and speed of transient blanching during copper vapour laser treatment of port-wine stains. Five watts of yellow (578 nm) light from a copper vapour laser was scanned over the lesion using a computer controlled scanning system. The clinical response of the lesion to treatment is transient blanching, followed immediately by erythema. The clinical response of sclerosed vessels is different in that an intravascular coagulum is observed. We measure the time taken for the lesion to blanch using two methods. First, high-speed photography is used to photograph the treatment process. Second, a photodiode measures the light re-emitted from the skin. Using illumination times of 3 to 5 ms and fluences of approximately 10 J cm-2, blanching times varied between 0 and 33 ms. We conclude that the cause of the transient blanching is not thermal denaturation of either collagen or epidermal melanin. Rather it is the rapid expulsion of red blood cells from the treated vessels. Our results have caused us to commence clinical trials using a new treatment protocol aimed at further improving the response of port-wine stains to copper vapour laser treatment.
    MeSH term(s) Biophysical Phenomena ; Biophysics ; Combined Modality Therapy ; Copper ; Humans ; Laser Therapy/adverse effects ; Laser Therapy/methods ; Photography ; Port-Wine Stain/surgery ; Port-Wine Stain/therapy ; Sclerotherapy ; Skin Pigmentation ; Telangiectasis/surgery ; Telangiectasis/therapy
    Chemical Substances Copper (789U1901C5)
    Language English
    Publishing date 1997-06
    Publishing country England
    Document type Journal Article
    ZDB-ID 208857-5
    ISSN 1361-6560 ; 0031-9155
    ISSN (online) 1361-6560
    ISSN 0031-9155
    DOI 10.1088/0031-9155/42/6/001
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  6. Article: High-resolution dosimetry using radiochromic film and a document scanner.

    Stevens, M A / Turner, J R / Hugtenburg, R P / Butler, P H

    Physics in medicine and biology

    1996  Volume 41, Issue 11, Page(s) 2357–2365

    Abstract: A method of reading exposed radiochromic film is described which has significant advantages over conventional densitometry. The method employs a document scanner and associated software for imaging the film. The resulting images are easily analysed using ...

    Abstract A method of reading exposed radiochromic film is described which has significant advantages over conventional densitometry. The method employs a document scanner and associated software for imaging the film. The resulting images are easily analysed using standard software to yield high-resolution dose maps. A calibration was performed which relates scanner signal to dose, allowing for the determination of dose at any point on an exposed film. Results obtained using a broad-band densitometer are compared to those where the scanner has been used. The technique was used to measure the dose distribution around a COMS-type ophthalmic applicator.
    MeSH term(s) Densitometry/methods ; Film Dosimetry/instrumentation ; Film Dosimetry/methods ; Humans ; Phantoms, Imaging ; Photons ; Reproducibility of Results ; Software ; Water ; X-Ray Film
    Chemical Substances Water (059QF0KO0R)
    Language English
    Publishing date 1996-11
    Publishing country England
    Document type Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 208857-5
    ISSN 1361-6560 ; 0031-9155
    ISSN (online) 1361-6560
    ISSN 0031-9155
    DOI 10.1088/0031-9155/41/11/008
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  7. Article: The facial distribution of port wine stains on patients presenting for laser treatment.

    Pickering, J W / Walker, E P / Butler, P H

    Annals of plastic surgery

    1991  Volume 27, Issue 6, Page(s) 550–552

    Abstract: During a 2-year period, 232 patients with port wine stains presented for laser treatment. They were analyzed for the position of the port wine stain with respect to the right and left ophthalmic, maxillary, and mandibular divisions of cranial nerve V and ...

    Abstract During a 2-year period, 232 patients with port wine stains presented for laser treatment. They were analyzed for the position of the port wine stain with respect to the right and left ophthalmic, maxillary, and mandibular divisions of cranial nerve V and the right and left cervical plexus. Fifty-one percent of the facial lesions were confined to either the right or left maxillary division, and 72% of the lesions were confined to just one of the eight nerve regions; 5.9% of the lesions occupied regions on both sides of the face, whereas 49.8% were confined to the right side and 44.3% to the left. In comparison with a group of 103 patients studied by Ohtsuka of Japan, there appeared to be significantly more patients in the maxillary division (p less than 0.0001) and significantly fewer patients in the ophthalmic division and in the combination of ophthalmic and maxillary divisions (p less than 0.00001).
    MeSH term(s) Adolescent ; Adult ; Bias ; Child ; Face/innervation ; Facial Neoplasms/epidemiology ; Facial Neoplasms/pathology ; Facial Neoplasms/surgery ; Humans ; Laser Therapy ; Nevus/epidemiology ; Nevus/pathology ; Nevus/surgery ; Skin Neoplasms/epidemiology ; Skin Neoplasms/pathology ; Skin Neoplasms/surgery
    Language English
    Publishing date 1991-12
    Publishing country United States
    Document type Journal Article
    ZDB-ID 423835-7
    ISSN 1536-3708 ; 0148-7043
    ISSN (online) 1536-3708
    ISSN 0148-7043
    DOI 10.1097/00000637-199112000-00006
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  8. Article ; Online: Spectroscopic (multi-energy) CT distinguishes iodine and barium contrast material in MICE.

    Anderson, N G / Butler, A P / Scott, N J A / Cook, N J / Butzer, J S / Schleich, N / Firsching, M / Grasset, R / de Ruiter, N / Campbell, M / Butler, P H

    European radiology

    2010  Volume 20, Issue 9, Page(s) 2126–2134

    Abstract: Objective: Spectral CT differs from dual-energy CT by using a conventional X-ray tube and a photon-counting detector. We wished to produce 3D spectroscopic images of mice that distinguished calcium, iodine and barium.: Methods: We developed a desktop ...

    Abstract Objective: Spectral CT differs from dual-energy CT by using a conventional X-ray tube and a photon-counting detector. We wished to produce 3D spectroscopic images of mice that distinguished calcium, iodine and barium.
    Methods: We developed a desktop spectral CT, dubbed MARS, based around the Medipix2 photon-counting energy-discriminating detector. The single conventional X-ray tube operated at constant voltage (75 kVp) and constant current (150 microA). We anaesthetised with ketamine six black mice (C57BL/6). We introduced iodinated contrast material and barium sulphate into the vascular system, alimentary tract and respiratory tract as we euthanised them. The mice were preserved in resin and imaged at four detector energy levels from 12 keV to 42 keV to include the K-edges of iodine (33.0 keV) and barium (37.4 keV). Principal component analysis was applied to reconstructed images to identify components with independent energy response, then displayed in 2D and 3D.
    Results: Iodinated and barium contrast material was spectrally distinct from soft tissue and bone in all six mice. Calcium, iodine and barium were displayed as separate channels on 3D colour images at <55 microm isotropic voxels.
    Conclusion: Spectral CT distinguishes contrast agents with K-edges only 4 keV apart. Multi-contrast imaging and molecular CT are potential future applications.
    MeSH term(s) Animals ; Barium Sulfate ; Contrast Media ; Diagnosis, Differential ; Ethiodized Oil ; Iohexol ; Mice ; Mice, Inbred C57BL ; Radiographic Image Enhancement/methods ; Radiographic Image Interpretation, Computer-Assisted/methods ; Radiography, Dual-Energy Scanned Projection/methods ; Reproducibility of Results ; Sensitivity and Specificity ; Spectrum Analysis/methods ; Tomography, X-Ray Computed/methods
    Chemical Substances Contrast Media ; Barium Sulfate (25BB7EKE2E) ; Iohexol (4419T9MX03) ; Ethiodized Oil (8008-53-5)
    Language English
    Publishing date 2010-03-23
    Publishing country Germany
    Document type Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1085366-2
    ISSN 1432-1084 ; 0938-7994 ; 1613-3749
    ISSN (online) 1432-1084
    ISSN 0938-7994 ; 1613-3749
    DOI 10.1007/s00330-010-1768-9
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  9. Article: A theoretical model of the blanching response after copper vapour laser treatment of telangiectasia.

    Marini, L / Butler, P H / Smithies, D J / Walker, E P

    The British journal of dermatology

    1992  Volume 127, Issue 2, Page(s) 189–191

    MeSH term(s) Blood Vessels/radiation effects ; Humans ; Laser Therapy ; Models, Biological ; Telangiectasis/radiotherapy
    Language English
    Publishing date 1992-08
    Publishing country England
    Document type Letter
    ZDB-ID 80076-4
    ISSN 1365-2133 ; 0007-0963
    ISSN (online) 1365-2133
    ISSN 0007-0963
    DOI 10.1111/j.1365-2133.1992.tb08059.x
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  10. Article: A computer controlled scanner for the laser treatment of vascular lesions and hyperpigmentation.

    Smithies, D J / Butler, P H / Pickering, J W / Walker, E P

    Clinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft fur Medizinische Physik and the European Federation of Organisations for Medical Physics

    1991  Volume 12, Issue 3, Page(s) 261–267

    Abstract: A computer controlled scanner has been used with a copper vapour laser for the treatment of vascular lesions and hyperpigmented lesions. The computer controls the position and speed of travel of the laser spot during treatment. The illumination time is ... ...

    Abstract A computer controlled scanner has been used with a copper vapour laser for the treatment of vascular lesions and hyperpigmented lesions. The computer controls the position and speed of travel of the laser spot during treatment. The illumination time is adjustable with a minimum of 1 ms. The light from the laser is scanned over the lesion so that the lesion is 'painted in' in a raster-like scan of arbitrary shape and produces a series of parallel lines 0.6 mm apart.
    MeSH term(s) Computers ; Hemangioma/radiotherapy ; Humans ; Laser Therapy ; Optics and Photonics ; Skin Neoplasms/radiotherapy
    Language English
    Publishing date 1991-08
    Publishing country England
    Document type Journal Article
    ZDB-ID 603089-0
    ISSN 0143-0815
    ISSN 0143-0815
    DOI 10.1088/0143-0815/12/3/007
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