Chin J Radiol 2003; 28:

Transcription

1 Chin J Radiol 2003; 28: modality console Image acquisition Quality assurance ISO Quality control PACS Picture Archiving and Communication System - Communication in Medicine [1] service WorkList PACS RIS - Digital Modality RIS 386 Reader Barcode

2 176 KVP, X-ray Tube Current, Exposure Time RIS CT non- FDA 1990 QC Scenario for SIEMENS CT HiQ 3.0 Network Plus MV-1000 (Auto send) Merge different studies into different series MWL SCU Manual match paitent information by 序號 query Q/R SCP/SCU Radwork QC modular (capacity over one month CT study) Manual adjust W/C (scope series) Save change (Status change to QCed) 1. Auto send if save successful 2. Send pending timer for save 3. Send/Receive queue PACS Archive Plus 4 1. support series sort image: by 1. Index no. 2. image no. 3. Acquisition no. 4. Slice Loc. 2. 可手動調整影像排列順序 3. Creatnew, split to, split series on.. modality Worklist SCP Defined Hanging protocol Auto delete (Albw stom setting) printer CT attribute tag Image Acquisition Context IAC HiQ Plus MV-1000 Radwork QC workstation window center window width VOI value of interest Tag series merging splitting PRINT 2a 2b

3 177 point of study time measurement report VOI value of interest window center / window width attribute tags Type 1, Type 2, and Type 3 attribute tags [ ] level 2 Server Presentation lookup table lung window bone window Patient level Study level Series level Image / instance level series level instance level proprietary image format vendor specifi/ modality LUT series merging series splitting image sorting 3 Hounsfield Unit HU or non- Computed Radiography: CR optic density OD console window center / window width VOI value of interest standard digital display system CRT TFT-LCD luminance ambient light characteristic curve Grayscale monitor Grayscale Standard Display Function [2] and drop drap CIE-lab

4 178 GSDF Grayscale Standard Display Function Barten s Curve [3] Photometer Barten s Curve Barten s Curve linear 4 perceptual linear 5% 95% JND: Just Noticeable Differences CD/m2 candela per square meter Presentation State SCOPE [4] OFFIS e.v., D Oldenburg, Germany PR I.O.D. Barten s model candela per square meter CD /m2 TFT mapping 10 bits 1021 grayscales limitation vendor 100 標準 Bartens 曲線 log10 luminance cd/m format transmission protocol 2-3 I.O.D. Presentation State Modality Type: PR [4,5] 0.1 Barten s linear 顯示器自有之特嵌曲線 DDL or P-Values Barten lookup table GSDF pixel data PR template CR 5

5 179 Type: DX DDL Digital Radiography X Modality VOI LUT module lookup table data element lookup table digital driving level VR type 2 VR NULL type 3 NULL Type 2C, Type 3C C conditional midtone Gamma correction, X PR Type 1, Type 2, and Type 3 attribute tags data element type 1 1. NEMA Standards Publication PS 3.x, Digital Imaging and Communications in Medicine (), National Electrical Manufacturers Association, 2101 L Street, N. W., Washington, D. C , NEMA Standards Publication PS 3.14, Digital Imaging and Communications in Medicine (), Part 14: Grayscale Standard Display Function, National Electrical Manufacturers Association, 2101 L Street, N. W., Washington, D.C , Barten, PGJ, Physical model for the contrast sensitivity of the human eye, Proceedings SPIE 1666, (1992) 4. Marco Eichelberga, Jörg Riesmeier, Klaus Kleber, Jörg Holstein, Herman Oosterwijk, Peter Jensch, Consistency of softcopy and hardcopy: Preliminary experiences with the new extensions for image display 5. Eichelberg M, Riesmeier J, Jensch P: Grayscale softcopy presentation states a new service for documenting image appearance in a softcopy environment, in: P. Rehak, H. Hutten: Medical & Biological Engineering & Computing 1999; 37(Suppl 2):

6 180 How to Do Quality Control Jobs Right for Digital Medical Images? TSUNG-LUNG YANG 1,2 WEI-CHUNG CHIEN 1 HUAY-BEN PAN 1,2 CHIEN-FAN YANG 1,2 Department of Radiology 1, Kaohsiung Veterans General Hospital School of Medicine 2, National Yang-Ming University Exactitude quality control (QC) jobs for medical images are indispensable for any modern hospital wishing to have a truly digital film-less or film-free environment with superb quality. Totally different from the quality control concept within the film-based dark room environment, to have the brand-new merits from digital quality assurance needs to equip yourself with the modern concepts and tools for the QC jobs. Basically the QC jobs could be consolidated in four aspects: 1. the completeness of patient demographic data and study information within the digital images. 2. the adjustment of value of interest (VOI) and sequence modification for series as well as instances. 3. careful selection and well calibration of the standard digital display system 4. display consistency within the medical environment either for diagnosis or browsing purposes. Within this article, we will discuss in detail using some examples based on these four QC jobs. Key words: ; Display-consistency; GSDF (Grayscale Standard Display Function); Quality control