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Munck af Rosenschöld, Per, et al.
(författare)
Current status of dosimetry at the boron neutron capture therapy facility at Studsvik, Sweden
2002
Ingår i: Research and Development in Neutron Capture Therapy. - 9788832329094 ; , s. 437-441
Konferensbidrag (refereegranskat) abstract
The beam was successfully characterized in air and in phantom using various radiation dosimeter:,. The determination of the thermal neutron and photon components of the mixed beam in phantom can be determined with acceptable uncertainties, while the uncertainty of the high-energy neutron component is considerable but of limited clinical significance. The beam intensity is sufficiently high for reasonably short treatment times. A novel approach to in-vivo dosimetry and quality assurance of treatment time in terms of monitor units was introduced in order to comply with national regulations regarding radiation therapy.
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Risberg, Jarl, et al.
(författare)
A new tomographic technique for absolute measurements of white and gray matter blood flow
2004
Ingår i: Proceedings of the 8th Nordic Meeting in Neuropsychology, Turku, Finland, August 26–29, 2004, 85.
Konferensbidrag (refereegranskat) abstract
Objective. Most methods for measurements of the regional cerebral blood flow are unable to provide absolute blood flow values. Until now interest has been focused on measurement of the gray matter blood flow, while the white matter blood flow has been rather neglected. The aim of the present project was to develop and evaluate an improved method for reliable tomographic measurements of absolute white and gray matter blood flow Method. The new tomographic method (modified Xe-SPECT) is based on an extension of the period of 133Xe inhalation from one to eight minutes followed by 22 instead of four minutes of breathing of ambient air. This gives a markedly enhanced signal from the white matter and better basis for correct quantification of the blood flow. The arrival and clearance of the tracer are recorded by a three head gamma camera system that provides flow maps with a spatial resolution of about one cm. Results The new method has been evaluated in 33 healthy younger and older (around 70 years) subjects as well as in a group of elderly patients with organic dementia. Our preliminary findings indicate that new and clinically valuable information is obtained by the improved Xe-SPECT method.
4.
Risberg, Jarl, et al.
(författare)
A new tomographic technique for absolute measurements of white and gray matter blood flow
2003
Ingår i: Journal of the International Neuropsychological Society. - 1355-6177. ; 9, s. 323-323
Konferensbidrag (refereegranskat) abstract
The integrity of the white matter is as important as that of the gray matter and white matter pathology has commonly been reported in elderly subjects and in patients with organic dementia. The aim of the present study is to develop and evaluate an improved method for reliable tomographic measurements of absolute white and gray matter blood flow. The new tomographic method (modified Xe-SPECT) is based on an extension of the period of 133Xe inhalation from one to eight minutes followed by 22 instead of four minutes of breathing of ambient air. This gives a markedly enhanced signal from the white matter and better basis for correct quantification pf the blood flow. The arrival and clearance of the tracer are recorded by a three head gamma camera system that provides flow maps with a spatial resolution of about one cm. The new method has been evaluated in healthy younger and older (around 70 years) subjects as well as in a group of elderly patients with organic dementia. Our preliminary findings indicate that new and clinically valuable information is obtained by the improved Xe-SPECT method
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Borga, Magnus, et al.
(författare)
FSED - feature selective edge detection
2000
Ingår i: Proceedings of 15th International Conference on Pattern Recognition, Barcelona. - : IEEE. - 0769507506
Konferensbidrag (refereegranskat) abstract
We present a method that finds edges between certain image features, e.g. gray-levels, and disregards edges between other features. The method uses a channel representation of the features and performs normalized convolution using the channel values as certainties. This means that areas with certain features can be disregarded by the edge filter. The method provides an important tool for finding tissue specific edges in medical images, as demonstrated by an MR-image example.
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