Flukeメーカー76-908の使用説明書/サービス説明書
ページ先へ移動 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.
デバイスFluke 76-908の購入後に（又は購入する前であっても）重要なポイントは、説明書をよく読むことです。その単純な理由はいくつかあります：
Fluke 76-908をまだ購入していないなら、この製品の基本情報を理解する良い機会です。まずは上にある説明書の最初のページをご覧ください。そこにはFluke 76-908の技術情報の概要が記載されているはずです。デバイスがあなたのニーズを満たすかどうかは、ここで確認しましょう。Fluke 76-908の取扱説明書の次のページをよく読むことにより、製品の全機能やその取り扱いに関する情報を知ることができます。Fluke 76-908で得られた情報は、きっとあなたの購入の決断を手助けしてくれることでしょう。
Fluke 76-908を既にお持ちだが、まだ読んでいない場合は、上記の理由によりそれを行うべきです。そうすることにより機能を適切に使用しているか、又はFluke 76-908の不適切な取り扱いによりその寿命を短くする危険を犯していないかどうかを知ることができます。
ですが、ユーザガイドが果たす重要な役割の一つは、Fluke 76-908に関する問題の解決を支援することです。そこにはほとんどの場合、トラブルシューティング、すなわちFluke 76-908デバイスで最もよく起こりうる故障・不良とそれらの対処法についてのアドバイスを見つけることができるはずです。たとえ問題を解決できなかった場合でも、説明書にはカスタマー・サービスセンター又は最寄りのサービスセンターへの問い合わせ先等、次の対処法についての指示があるはずです。
