Gebruiksaanwijzing /service van het product 76-908 van de fabrikant Fluke
Ga naar pagina of 26
Nuclear Associates 76-907 and 76-908 AAPM MRI Phantoms Users Manual March 2005 Manual No. 38616 Rev. 3 © 2003, 2005 Fluke Corporat i on, All rights reserved .
Fluke Biomedical Radiation Management Services 6045 Cochran Road Cleveland, Ohio 44139 440.498.2564 www.flukebiomedical.com/rms.
i Table of Contents Section 1: General Info rmation ................................................................................... 1-1 1.1 Introduc tion .............................................................................................
(Blank page).
General Information Introduction 1 1-1 Section 1 General Information 1.1 Introduction This user's manual descr ibes a set of MRI phantoms that we re manufactured ba sed on the AAPM recommendations and thei r use in measuring t he MRI system performan ce.
Nuclear Associates 76-908 & 76-907 Operators Manual 1-2 1.2.1 3D Resolution and Slice (3DRAS) Phantom (Model 76-908) The 3DRAS phantom has outer dim ensions of 6" x 6" x 5" (Figure 1-1).
General Information Phantom Description 1 1-3 Figure 1-3. Resolution Sections in Three Imaging Pl anes The slice-thickness phanto m consists of two crossed thin ramps (Figure 1-4 ). Figure 1-4. Slice Thickness Phantom Triangular blocks make 4" x 4" sq uare with diagonal gaps of 1 or 2 mm.
Nuclear Associates 76-908 & 76-907 Operators Manual 1-4 A ramp-crossing angle of 90° yields an a ngle of 45° between the ramp and the imaging slice plane. Ea ch slice thickness section con sists of four triangular blocks arrang ed to form (signal producing) h ot ramps filling the gaps of 1 mm or 2 mm (Figure 1-5).
General Information Phantom Description 1 1-5 MR Phantom for Spatial Linearity, Signal-To-Noise, and Image Artifact Figure 1-6. UAL Phantom MRI Phantom for Spatial Linearity, Signal-To-Noise, and Image Artifact Figure 1- 7.
Nuclear Associates 76-908 & 76-907 Operators Manual 1-6 The flood phantom has a uniform solution, the image of which can be used to measure the uniformity in signal intensity in the images. The grid section con s ists of grids that can be used to assess geometri c linearity.
Operation Phantom Preparation 2 2-1 Section 2 Operation 2.1 Phantom Preparation The phantoms can be shipped filled with solutions or solutions can be shipped separately.
Nuclear Associates 76-908 & 76-907 Operators Manual 2-2 2.2 Preparation for Scanning 2.2.1 Positioning the Phantom The 3DRAS phantom can be pla ced in a head coil or a body coil. The center of the phantom should coincide approximately with the center of the RF coil.
Operation Tests with 3D Resolution and Slice (3DRAS) Phantom 2 2-3 resonance frequency adju stment and some may be completely automated. Resonance frequency shoul d be recorded daily for trend analysis. Values of resonance frequency should gene rally not deviate by more tha n 50 ppm between successive daily measurements.
Nuclear Associates 76-908 & 76-907 Operators Manual 2-4 • The high contrast resolution should rem ain constant for repeated measurements und er the same scan conditions and should be equ al to the pixel size. For example, for a 25.6 cm field of view with a 256 x 256 acquisitions m atrix, the resolution should be 1 mm.
Operation Tests with 3D Resolution and Slice (3DRAS) Phantom 2 2-5 direction) is measured and relate d to the slice posi tion. For a 45° ramp, the distance from a centered reference pin to the slice profile midpoint will be equ al to the point of the ramps located at the isocenter.
Nuclear Associates 76-908 & 76-907 Operators Manual 2-6 Figures 2-2 and 2-3 represent two adja cent sagital vi ews of the phantom. The resolution hole s are well resolved in vertical and ho rizontal direction and the two slices are 6 mm apart (SP = 14.
Operation Tests with 3D Resolution and Slice (3DRAS) Phantom 2 2-7 Figures 2-4 and 2-5 show two adj acent coronal view s of the phantom. The slice thickne ss lines of 1 mm ramps on the right and bottom of the images are too faint to be seen . Figure 2-5 Figure 2-4.
Nuclear Associates 76-908 & 76-907 Operators Manual 2-8 Figure 2-6 shows a resolution hole imag e against a background le ss opaque than in previou s images, indicating that the position of the resolution blo ck is su ch that it is partially covered by the slice.
Operation Tests with 3D Resolution and Slice (3DRAS) Phantom 2 2-9 Figures 2-7 and 2-8 show an exampl e of the slice thickness measureme nt analysis. A signal intensity profile is drawn vertically through a set of slice thi c kness ramp Images. The profile is the sli ce thickness profile.
Nuclear Associates 76-908 & 76-907 Operators Manual 2-10 2.4 Tests With Uniformity and Linearity (UAL) Phantom 2.4.1 Image Uniformity Image uniformity refers to the ability of the MR imag ing syste m to produce a constant signal re sponse throughout the scanned volume when th e object bei ng imaged has homogeneou s MR characteristics.
Operation Tests with Uniformity and Linea rity (UAL) Phantom 2 2-11 (2) Non-linear m agnetic field gradients Variability is best observed over the largest field-of-view. The phantom should occupy at least 60% of the largest field-of-view. Figu re 1-1 provides an illustration of a patte rn that is used to evaluate spatial linearity.
Nuclear Associates 76-908 & 76-907 Operators Manual 2-12 DC-Offset Errors DC-offset errors typically appear a s a single bright pixel (sometimes a s a dark pixel if overflow or processing has occurred) at the center of the image matrix. The existence of this error is a ssessed visually.
Operation Tests with Uniformity and Linea rity (UAL) Phantom 2 2-13 Figure 2-9.
Nuclear Associates 76-908 & 76-907 Operators Manual 2-14 Figure 2-10 is a flood image showing the uniformity o f si gnal intensity. Field non-uniformit y is also shown on the outer edges. Figure 2-10 Figure 2-11 shows a horizont al inten sity profile with a narrow window setting.
Operation Tests with Uniformity and Linea rity (UAL) Phantom 2 2-15 Figure 2-12 is an image of the signal bubble for quadr ature e rror. If there were any quadrature phase error, another ghost circle woul d be visible in the lo wer right-hand corne r of the image.
Fluke Corporation Radiation Management Services 6045 Cochran Road Cleveland, Ohio 44139 440.498.2564 www.flukebiomedical.com/rms.
Een belangrijk punt na aankoop van elk apparaat Fluke 76-908 (of zelfs voordat je het koopt) is om de handleiding te lezen. Dit moeten wij doen vanwege een paar simpele redenen:
Als u nog geen Fluke 76-908 heb gekocht dan nu is een goed moment om kennis te maken met de basisgegevens van het product. Eerst kijk dan naar de eerste pagina\'s van de handleiding, die je hierboven vindt. Je moet daar de belangrijkste technische gegevens Fluke 76-908 vinden. Op dit manier kan je controleren of het apparaat aan jouw behoeften voldoet. Op de volgende pagina's van de handleiding Fluke 76-908 leer je over alle kenmerken van het product en krijg je informatie over de werking. De informatie die je over Fluke 76-908 krijgt, zal je zeker helpen om een besluit over de aankoop te nemen.
In een situatie waarin je al een beziter van Fluke 76-908 bent, maar toch heb je de instructies niet gelezen, moet je het doen voor de hierboven beschreven redenen. Je zult dan weten of je goed de alle beschikbare functies heb gebruikt, en of je fouten heb gemaakt die het leven van de Fluke 76-908 kunnen verkorten.
Maar de belangrijkste taak van de handleiding is om de gebruiker bij het oplossen van problemen te helpen met Fluke 76-908 . Bijna altijd, zal je daar het vinden Troubleshooting met de meest voorkomende storingen en defecten #MANUAl# samen met de instructies over hun opplosinge. Zelfs als je zelf niet kan om het probleem op te lossen, zal de instructie je de weg wijzen naar verdere andere procedure, bijv. door contact met de klantenservice of het dichtstbijzijnde servicecentrum.
