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Electronic Modification of the Scintigram and its Limitations; Modification Electronique des Scintigrammes: Limitations; Ehlektronnoe usovershenstvovanie stsintigrammy i ego ogranicheniya; Modificacion Electronica de los Centelleogramas: Sus Limitaciones

Conference:

Abstract

An investigation of the basic principles of contrast enhancement is presented. Certain fundamental laws should be observed in the design of transforming systems as well as in their application in order to visualize a maximum of information. These laws are developed using the following parameters and functions, which in general characterize all kinds of transforming systems: (1) The elementary cell of primary information, defined by time intervals or pre-selected number of counts etc; (2) The information-transforming function, according to which the elementary cell is represented in the scintigram (by the degree of blackening of a photo-dot, for example). Often this function is regarded as the final characteristic of the transforming system; this is true, however, only when statistical fluctuations are negligible. The behaviour of a transforming system including statistical fluctuations is described by the following functions, which show the quality of a scintigram in quantitative terms. (3) The picture-generating function, according to which the mean value of counting rate over an area is transformed into a mean blackening of the corresponding area in the scintigram. This function gives the contrast enhancement. (4) The significance function, which describes the loss of information caused by the transformation. This function gives the degree  More>>
Authors:
Conrad, B.; Horst, W. [1] 
  1. University Clinic for Radiotherapy and Nuclear Medicine Cantonal Hospital, Zurich (Switzerland)
Publication Date:
Oct 15, 1964
Product Type:
Conference
Report Number:
IAEA-SM-51/82
Resource Relation:
Conference: Symposium on medical radioisotope scanning, Athens (Greece), 20-24 Apr 1964; Other Information: 6 refs., 15 figs.; Related Information: In: Medical Radioisotope Scanning. Vol. I. Proceedings of the Symposium on Medical Radioisotope Scanning| 574 p.
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; BRAIN; COUNTING RATES; MODIFICATIONS; NUCLEAR MEDICINE; RADIOISOTOPE SCANNING
OSTI ID:
22127653
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M3066082732
Submitting Site:
INIS
Size:
page(s) 491-506
Announcement Date:
Sep 12, 2013

Conference:

Citation Formats

Conrad, B., and Horst, W. Electronic Modification of the Scintigram and its Limitations; Modification Electronique des Scintigrammes: Limitations; Ehlektronnoe usovershenstvovanie stsintigrammy i ego ogranicheniya; Modificacion Electronica de los Centelleogramas: Sus Limitaciones. IAEA: N. p., 1964. Web.
Conrad, B., & Horst, W. Electronic Modification of the Scintigram and its Limitations; Modification Electronique des Scintigrammes: Limitations; Ehlektronnoe usovershenstvovanie stsintigrammy i ego ogranicheniya; Modificacion Electronica de los Centelleogramas: Sus Limitaciones. IAEA.
Conrad, B., and Horst, W. 1964. "Electronic Modification of the Scintigram and its Limitations; Modification Electronique des Scintigrammes: Limitations; Ehlektronnoe usovershenstvovanie stsintigrammy i ego ogranicheniya; Modificacion Electronica de los Centelleogramas: Sus Limitaciones." IAEA.
@misc{etde_22127653,
title = {Electronic Modification of the Scintigram and its Limitations; Modification Electronique des Scintigrammes: Limitations; Ehlektronnoe usovershenstvovanie stsintigrammy i ego ogranicheniya; Modificacion Electronica de los Centelleogramas: Sus Limitaciones}
author = {Conrad, B., and Horst, W.}
abstractNote = {An investigation of the basic principles of contrast enhancement is presented. Certain fundamental laws should be observed in the design of transforming systems as well as in their application in order to visualize a maximum of information. These laws are developed using the following parameters and functions, which in general characterize all kinds of transforming systems: (1) The elementary cell of primary information, defined by time intervals or pre-selected number of counts etc; (2) The information-transforming function, according to which the elementary cell is represented in the scintigram (by the degree of blackening of a photo-dot, for example). Often this function is regarded as the final characteristic of the transforming system; this is true, however, only when statistical fluctuations are negligible. The behaviour of a transforming system including statistical fluctuations is described by the following functions, which show the quality of a scintigram in quantitative terms. (3) The picture-generating function, according to which the mean value of counting rate over an area is transformed into a mean blackening of the corresponding area in the scintigram. This function gives the contrast enhancement. (4) The significance function, which describes the loss of information caused by the transformation. This function gives the degree of regularity of representation. On the basis of the above definitions, the paper deals with the following problems: optimal ''size'' of the primary information cell, depending on the resolution of the detector; optimal shape of transforming function for various purposes; some electronic circuits for realization of such functions. In particular, an apparatus is described in detail which gives an optimum of linear presentation using a suitable selected non- linear transforming function. Thus the range of net counting rate between background and maximal counting rate is projected to the full range of blackening in the scintigram in a manner that provides a minimum of falsification of data. Also other kinds of presentation can be selected, for example various quasi- logarithmic characteristics. The problem of contrast enhancement in the case of extremely small differences, for example in brain tumour scanning, is discussed in detail. It should be noted that the principles described could be applied not only to scanners, but also to stationary detectors of every kind. (author) [French] Les auteurs etudient les principes qui sont a la base de l'accentuation du contraste. Certaines lois fondamentales devraient etre observees dans la realisation et l'utilisation des systemes de conversion, afin de permettre la visualisation d'un maximum d'informations. Pour determiner ces lois, on a utilise les parametres et fonctions ci-apres, qui caracterisent en regle generale tous les systemes de conversion: 1. L'element fondamental d'information primaire, qui est defini par les intervalles de temps, le nombre de coups determine a l'avance, etc. 2. La fonction de conversion de l'information, qui permet de representer l 'element fondamental dans le scintigramme (par exemple, degre de noircissement d'un point photographique). Cette fonction est souvent consideree comme etant la caracteristique essentielle du systeme de conversion, mais cela n'est vrai que si les fluctuations statistiques sont negligeables. Le comportement d'un systeme de conversion, y compris les fluctuations statistiques, est decrit par les fonctions suivantes, qui expriment quantitativement la qualite d'un scintigramme 3. Fonction de production d'images, qui exprime la valeur moyenne du taux de comptage au-dessus d'une zone par un noircissement moyen de la zone correspondante du scintigramme; cette fonction assure l'accentuation du contraste. 4. Fonction d'evaluation, qui indique les pertes d'informations dues a la conversion. Elle montre le degre de regularite de la representation. En s'appuyant sur les definitions ci-dessus, les auteurs traitent des problemes ci-apres: 'dimension' optimum de l'element d'information primaire, en fonction du pouvoir de resolution du detectuer; forme optimum de la fonction de conversion suivant l 'objet de l'examen scintigraphique; circuits electroniques permettant de realiser ces fonctions. En particulier, les auteurs decrivent en detail un appareil qui assure une presentation lineaire optimum grace a une fonction de conversion non lineaire appropriee. Ainsi, la gamine des taux de comptage nets, allant du bruit de fond au taux de comptage maximum, se trouve representee dans le scintigramme par toutes les nuances de noircissement, d'une maniere qui reduit a un minimum l'alteration des donnees. On peut aussi choisir d'autres genres de presentation, par exemple differentes caracteristiques quasi-logarithmiques. Le probleme de l'accentuation du contraste lorsque les nuances sont tres faibles, par exemple dans l'exploration des tumeurs du cerveau, sera traite de maniere detaillee. Il est a noter que les principes exposes peuvent s'appliquer non seulement aux detecteurs mobiles utilises en scintigraphie, mais aussi aux detecteurs stationnaires de tous genres. (author) [Spanish] Los autores estudian los principios basicos del aumento del contraste. Al realizar y utilizar los sistemas de conversion deberian observarse cienas leyes fundamentales a fin de permitir la visualizacion del maximo de informaciones. Para determinar esas leyes se han utilizado Los siguientes parametros y funciones, que caracterizan, en general, todos los sistemas de conversion: 1. El elemento fundamental de informacion primaria, definido por los intervalos de tiempo, el numero predeterminado de impulsos, etc . 2. La funcion de conversion de las informaciones, que permite representar el elemento fundamental en el centelleograma (e l grado de ennegrecimiento de un punto luminoso, por ejemplo). A menudo esta funcion se considera como la caracteristica esencial del sistema de conversion, pero esto solo es cierto si las fluctuaciones estadisticas son despreciables. El comportamiento de un sistema de conversion, incluidas las fluctuaciones estadisticas, es descrito por las funciones siguientes, que expresan cuantitativamente la calidad de un centelleogtama: 3. Funcion de produccion de imagenes: expresa el valor medio del fndice de recuento correspondiente a una zona con un ennegrecimiento medio de la zona correspondiente del centelleograma. Esta funcion asegura el aumento del contraste. 4. Funcion significativa, que indica las perdidas de informacion debidas a la conversion. Esta funcion muestra el grado de regularidad de la representacion. Basandose en dichas definiciones, los autores estudian los siguientes problemas: 'Dimension' optima del elemento de informacion primario en funcion del poder de resolucion del detector. Forma optima de la funcion de conversion segun el objeto de la exploracion centelleografica. Circuitos electronicos que permiten realizar dichas funciones. En particular, los autores describen detalladamente un aparato que da una presentacion lineal optima gracias a una funcion de conversion no lineal apropiada. Asi el intervalo de los fndices netos de recuento comprendidas entre el fondo y el fndice de recuento maximo se halla representado en el centelleograma por grados de emegrecimiento de una manera que reduce al minimo la alteracion de los datos. Se pueden seleccionar otros tipos de presentacion, por ejemplo, diferentes caracteristicas cuasilogaritmicas. Los autores estudian detenidamente el problema del aumento del contraste cuando las diferencias son extremadanente pequenas, por ejemplo, en la exploracion de tumores cerebrales. Conviene advertir que los principios enunciados pueden aplicarse no solo a los detectors moviles, sino tambien a los detectores fijos de cualquier tipo. (author) [Russian] Predstavleno i ssledovanie osnovnyh principov kon trastnogo usilen i ja . Prirazrabotk e transformirujushhih si st em , a takzhe pri ih primenenii neobhodimo sobljudat' nekotorye o s novnye zakonomernosti dlja togo, chtoby poluchit' maksimum informacii. Jeti zak on om ernosti razrabotany pri ispol'zovanii sledujushhih parametrov i funkcij, kotorye v celom harakterizujut transformirujushhie sistemy vseh vidov: 1. Jelementarnaja jachejka pervichnoj informacii, opredelja em aja intervalami vremeni ili predvaritel'no otobrannym chislom o tschetov, it.d. 2. Funkcija preobrazovanija informacii, v sootvetstvii s kotoroj jelementarnaja jachejka . predstavljaetsja na scintigramme (naprimer, stepen'ju potemnenija fotopjatna). Chasto jet a funkcija r a ssmatri v aet sja kak okonchatel'naja harakteristika transformirujushhej sistemy; odnako jet o spravedlivo tol'ko pri neznachitel'nyh statisticheskih kolebanijah. 4 Povedenie transformirujushhej si st emy , vkljuchaja st atisticheskie kolebanija, opisyvaetsja sledujushhimi funkcijami, kotorye pokazyvajut kachestvo scintigrammy s kolichestvennoj tochki zrenija. 3. Funkcija generacii snimka, v sootvetstvii s kotoroj srednjaja velichina skorosti scheta v zon e transformiruetsja v sredne e potemnenie sootvetstvujushhej zony na scintig ramme. Jeta funkcija da et kontrastnoe usi lenie. 4. Funkcija dostovernosti, kotoraja opisyvaet poterju informacii, prichinennuju transformaciej. Jeta funkcija da et stepen' pravil'nosti vosproizvedenija izobrazhenija. Na osnove vysheukazannyh opredelenij v doklade rassmatrivajutsja sledujushhie problemy: optimal'nyj ''razmer'' jachejki pervichnoj informacii v zavisimosti ot razreshajushhej sposobnosti detektora; optimal'naja forma transformirujushhej funkcii dlja razlichnyh celej; nekotorye jelektronnye kontury dlja realizacii takih funkcij. V chastnosti budet podrobno opisan pribor, kotoryj daet optimal'noe znachenie linejn ogo predstavlenija pri ispol'zovanii sootvetstvujushhim obra zom podobrannoj nelinejnoj transformirujushhej funkcii. Takim obrazom, interval chistoj skorosti scheta v promezhutke mezhdu fonovoj i maksimal'noj skorost'ju scheta proeciruetsja kak potemnenie v polnom intervale na scintigramme takim obrazom, chto jeto obespechivaet minimal'noe iskazhenie dannyh. Mozhno takzhe otobrat' drugie vidy predstavlenija, naprimer razlichnye kvazi-loga - rifmicheskie harakteristiki. Podrobno obsuzh d a et sja problema kontrastnogo usilenija v sluchae chrezvychajno malyh razlichij, naprimer na skennogramme m ozgovoj opuholi. Sleduet otmetit', chto vysheopisannye principy mogut primenjat'sja ne tol'ko k sken- neram, no i k stacionarnym detektoram ljubogo vida. (author)}
place = {IAEA}
year = {1964}
month = {Oct}
}