| 11. |
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| 12. |
- Maguire Jr., Gerald Q., et al.
(författare)
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Looking Back at Medical Image Processing
- 1986
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Ingår i: Administrative Radiology. - : Association Of University Radiologists. - 0738-6974. ; 5:11
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Tidskriftsartikel (refereegranskat)
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| 13. |
- Maguire Jr., Gerald Q.
(författare)
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Picture Archiving and Communications Systems : Progress and Current Problems
- 1988
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Ingår i: Medical Images: Formation, Handling and Evaluation - Proceedings of the NATO Advanced Study Institute on the Formation, Handling and Evaluation of Medical Images. - : Springer-Verlag Berlin and Heidelberg GmbH & Co. K. - 9783540561316
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 14. |
- Maguire Jr., Gerald Q.
(författare)
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Picture Archiving, Processing, and Communication (PACS)
- 1985
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Ingår i: The Computation of dose distributions in electron beam radiotherapy. - Umeå, Sweden : Umeå University. - 9789171741776 - 9171741771 ; , s. 341-342
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Bokkapitel (refereegranskat)
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| 15. |
- Noz, Marilyn E., et al.
(författare)
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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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| 16. |
- Ljungberg, Michael, et al.
(författare)
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A Monte Carlo program for the simulation of scintillation camera characteristics
- 1989
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Ingår i: Computer Methods and Programs in Biomedicine. - : Elsevier BV. - 0169-2607. ; 29:4, s. 257-272
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for mathematical modelling for the evaluation of important parameters for photon imaging systems. A Monte Carlo program which simulates medical imaging nuclear detectors has been developed. Different materials can be chosen for the detector, a cover and a phantom. Cylindrical, spherical, rectangular and more complex phantom and source shapes can be simulated. Photoelectric, incoherent, coherent interactions and pair production are simulated. Different detector parameters, e.g. the energy pulse-height distribution and pulse pile-up due to finite decay time of the scintillation light emission, can be calculated. An energy resolution of the system is simulated by convolving the energy imparted with an energy-dependent Gaussian function. An image matrix of the centroid of the events in the detector can be simulated. Simulation of different collimators permits studies of spatial resolution and sensitivity. Comparisons of our results with experimental data and other published results have shown good agreement. The usefulness of the Monte Carlo code for the accurately simulation of important parameters in scintillation camera systems, stationary as well as SPECT (single-photon emission computed tomography) systems, has been demonstrated.
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| 17. |
- Ekberg, Lars, et al.
(författare)
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What margins should be added to the clinical target volume in radiotherapy treatment planning for lung cancer?
- 1988
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Ingår i: Radiotherapy and Oncology. - 1879-0887. ; 48:1, s. 71-77
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The planning target volume in radiotherapy treatment planning takes into account both movements of the clinical target volume (CTV) and set-up deviations. MATERIALS AND METHODS: A group of patients who received radiotherapy for lung cancer were studied. In order to measure the CTV movements due to respiration and other internal organ motions, fluoroscopy was performed for 20 patients. To study the accuracy and reproducibility of patient and beam set-up, 553 electronic portal images from 20 patients were evaluated. Discrepancies between planned and actual field positions were measured and the systematic and random errors were identified. The combined effect of these geometrical variations was evaluated. RESULTS: The average CTV movement with quiet respiration was about 2.4 mm in the medio-lateral and dorso-ventral directions. Movement in the cranio-caudal direction was on average 3.9 mm with a range of 0-12 mm. The systematic set-up errors were on average 2.0 mm in the transversal plane and 3.0 mm in the cranio-caudal direction. The random errors can be described by their standard deviations of 3.2 and 2.6 mm. In this study, the combined effect of the two parameters (CTV movement and set-up deviations) varied between 7.5 and 10.3 mm in different anatomical directions. CONCLUSIONS: In our daily clinical routine, we use a margin of 11 mm in the transversal plane and 15 mm cranially and caudally, also taking into account other unquantified variations and uncertainties.
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| 18. |
- Geborek, Pierre, et al.
(författare)
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Measurement of oxygen and carbon dioxide partial pressures in synovial fluid after tonometry
- 1988
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Ingår i: Clinical Physiology. - 1365-2281. ; 8:4, s. 427-432
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Tidskriftsartikel (refereegranskat)abstract
- A commercially available gas analyser was used to measure tension of oxygen (PO2) and carbon dioxide (PCO2) in synovial fluid samples after tonometry. Measured values of PCO2 were close to the expected (median difference 0.2 kPa, range -0.4 to 0.4) within the analysed concentration range of 4-10 kPa. No consistent difference between measured and expected values of PO2 were found for oxygen in the range 3-11 kPa (median difference 0.1 kPa, range -0.3 to 1.2). For oxygen tensions below 3 kPa, however, the measured values invariably overestimated the actual PO2, the errors ranging from 0.3 to 1.9 kPa, median 1.1. The importance of proper handling of samples was investigated and storage for 1 h at 0 degrees C in plastic syringes resulted in elevation of the PO2 levels measured (range of elevation 0.2 to 3.6 kPa, median 1.15), whilst no significant differences were found when stored in glass syringes. Within the limits stated, commercially available gas analysers may thus be used to investigate these parameters related to local tissue metabolism in effusive joint conditions.
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| 19. |
- Kjellén, Elisabeth, et al.
(författare)
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Comparison of low dose nicotinamide versus benzamide, administered per os, as radiosensitizers in a C3H mammary carcinoma
- 1988
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Ingår i: Radiotherapy and Oncology. - : Elsevier BV. - 1879-0887 .- 0167-8140. ; 12:4, s. 327-331
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Tidskriftsartikel (refereegranskat)abstract
- We have evaluated if any differences in tumor radiosensitization exist between the two adenosine diphosphate ribosyl transferase (ADPRT) inhibitors nicotinamide and benzamide at fractionated low doses. A significant radiosensitizing effect with nicotinamide at a 10 mg/kg per day dose was found in the tumor model used. We found, however, no radiosensitizing effect with benzamide given according to this schedule.
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| 20. |
- Lindholm, Clas-Ebbe, et al.
(författare)
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Microwave-induced hyperthermia and radiotherapy in human superficial tumours: clinical results with a comparative study of combined treatment versus radiotherapy alone
- 1987
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Ingår i: International Journal of Hyperthermia. - : Informa UK Limited. - 0265-6736 .- 1464-5157. ; 3:5, s. 393-411
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Tidskriftsartikel (refereegranskat)abstract
- Eighty-five evaluable superficial recurrent malignant tumours, mainly adenocarcinomas (78 per cent), in 38 patients were treated with either combined local hyperthermia (41-45 degrees C for four sessions) and low dose radiotherapy (30.0 Gy) or the same low dose radiotherapy alone. The treatment was given for two weeks. Hyperthermia was induced externally with 2450 MHz or 915 MHz microwaves. Totally 57 tumours were given combined treatment with a complete and partial response rate of 46 and 30 per cent, respectively (duration 1-38 months). In 18 patients with 2-10 superficial tumours each, 56 tumours were used in a comparative study, comparing the effect of combined hyperthermia and low dose radiotherapy versus the same low dose radiotherapy alone, the patients acting as their own controls. The total response rates were 89 and 50 per cent, respectively, in the two treatment modality groups. The difference in response rates is significant (p = 0.0039) in favour of the combined treatment, and this is also found when comparing complete remissions only (p = 0.0027). Local pain and normal tissue reactions presented problems during and after 2450 MHz microwave-induced hyperthermia treatment, performed without a coupling water bag system. Introduction of 915 MHz microwave-induced hyperthermia with a coupling deionized water bag system and refinement of microwave applicators, as well as the temperature control system considerably reduced these problems.
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