| 61. |
- Maguire Jr., Gerald Q., et al.
(författare)
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Standardizing the raster display for medical images using a fixed set of frame buffer primitives
- 1986
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Ingår i: Journal of medical systems. - : Springer. - 0148-5598 .- 1573-689X. ; 10:3, s. 209-228
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Tidskriftsartikel (refereegranskat)abstract
- Two major difficulties associated with medical image processing are the diverse image formats that must be dealt with because of the differences in image sources and the number of incompatible display systems available for viewing images both before and after processing. We describe a very small set of primitives that need to be defined to utilize any raster display. When these primitives have been implemented for a particular device, then a standard set of image display programs can be compiled and images and the results of image processing can be displayed. The main purpose of this paper is to describe what a raster display looks like from the point of view of the programmer and to define the specific hardware and software data about the raster display that must be known in order to implement the small set of primitives.
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| 62. |
- Maguire Jr., Gerald Q., et al.
(författare)
-
Use of graphical techniques for error evaluation
- 1987
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Ingår i: Journal of medical systems. - : Springer. - 0148-5598 .- 1573-689X. ; 11:4, s. 277-286
-
Tidskriftsartikel (refereegranskat)abstract
- Anatomic localization in functional (such as PET) imaging often requires a structural (such as CT or NMRI) study of the brain in the same plane. Some neuropsychiatric conditions make it difficult for a patient to hold his/her head immobile even when a rigid head holder is used. We studied the effect of tilt of the anatomic reference image, in this instance CT, relative to the functional image, here PET, on the quantification of receptor ligand concentration in anatomically defined regions of the brain.
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| 63. |
- Nilsson, M, et al.
(författare)
-
Quantitative computed tomography in measurement of vertebral trabecular bone mass. A modified method
- 1988
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Ingår i: Acta Radiologica. - 1600-0455. ; 29:6, s. 719-725
-
Tidskriftsartikel (refereegranskat)abstract
- Measurement of bone mineral concentration (BMC) can be done by several modalities. Quantitative computed tomography (QCT) can be used for measurements at different sites and with different types of bone (trabecular-cortical). This study presents a modified method reducing the influence of fat. Determination of BMC was made from measurements with single-energy computed tomography (CT) of the mean Hounsfield number in the trabecular part of the L1 vertebra. The method takes into account the age-dependent composition of the trabecular part of the vertebra. As the amount of intravertebral fat increases with age, the effective atomic number for these parts decreases. This results in a non-linear calibration curve for single-energy CT. Comparison of BMC values using the non-linear calibration curve or the traditional linear calibration with those obtained with a pixel-by-pixel based electron density calculation method (theoretically better) showed results clearly in favor of the non-linear method. The material consisted of 327 patients aged 6 to 91 years, of whom 197 were considered normal. The normal data show a sharp decrease in trabecular bone after the age of 50 in women. In men a slower decrease was found. The vertebrae were larger in men than in women.
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| 64. |
- Nilsson, Per, et al.
(författare)
-
Computer controlled microwave system for clinical hyperthermia
- 1985
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 30:4, s. 283-292
-
Tidskriftsartikel (refereegranskat)abstract
- A hyperthermia system which has been developed for clinical use is described. Different direct-contact applicators working at the ISM microwave frequency of 915 MHz are used for inducing heat in superficial tumours to a depth of about 3 cm. The system is a further development of an earlier prototype which worked at 2450 MHz. The microwave generator is controlled by a microcomputer governed by temperature measurements with thermistor probes inserted into the tissue. To minimise the influence of the interaction between the microwaves and the temperature probes, a pulsed irradiation technique is used. Up to July 1984, 80 superficial tumours had been treated with radiotherapy combined with local hyperthermia applied using this system.
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| 65. |
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| 66. |
- Noz, Marilyn E., et al.
(författare)
-
Graphical Aids for Tomographic Image Correlation
- 1985
-
Ingår i: Computer assisted radiology. - West Berlin, FRG : Springer-Verlag Berlin. - 9783540155201 - 3540155201 ; , s. 608-611
-
Konferensbidrag (refereegranskat)
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| 67. |
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| 68. |
- Noz, Marilyn E., et al.
(författare)
-
Multimodality image display : Desirable frame buffer characteristics
- 1988
-
Ingår i: Journal of medical systems. - : Springer Netherlands. - 0148-5598 .- 1573-689X. ; 12:4, s. 189-200
-
Tidskriftsartikel (refereegranskat)abstract
- The intent of this paper is to understand the characteristics of those frame buffers currently used to display images, versus more ideal frame buffers for medical image display purposes. This study is based on current needs and what characteristics might be desirable. Two case examples are presented: (1) a system developed for high quality computer graphics and (2) a system developed for nuclear medicine and radiation therapy treatment planning. Our study considers: (1) defining a pixel depth sufficient to hold data, (2) the desirability of multiple color look-up tables, (3) how cine loops are managed, and (4) display memory size.
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| 69. |
- Noz, Marilyn E., et al.
(författare)
-
QSH : a minimal but highly portable image display and handling toolkit
- 1988
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Ingår i: Computer Methods and Programs in Biomedicine. - : ELSEVIER SCI IRELAND LTD. - 0169-2607 .- 1872-7565. ; 27:3, s. 229-240
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Tidskriftsartikel (refereegranskat)abstract
- We describe a software system developed to handle images obtained from different sources, namely, computer-assisted tomography, positron emission tomography, single photon emission tomography and magnetic resonance imaging. In developing the system, it was necessary to address the following points. (1) The types of values that were encountered in both the header information and the pixel elements, namely, integers, floating point numbers, complex numbers and strings. (2) The use of domain-dependent sets of keys, that is, how to choose keys and how to stabilize the use of keys among the user population. This is, for example, how information such as the patient name, or the activity in becquerel is kept. It is necessary to keep both the key values and the units. (3) The development of a method for providing a database using flat files, i.e. linear text. (4) The maintenance of a history of values and operations. This is necessary in order to address the problem of determining from an image was produced. The connection between an image and how it was derived is analogous to describing how a secondary standard is derived from a primary one.
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| 70. |
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