查看“︁亨氏單位”︁的源代码

'''亨氏單位'''（{{lang-en|Hounsfield unit}}，[[縮寫]]：{{lang|en|HU}}），為'''亨氏量表'''（{{lang|en|Hounsfield scale}}）{{le|阻射率|Radiodensity}}的數量尺度單位，命名自[[X射線電腦斷層掃描]]的發明人[[高弗雷·豪斯費爾德]]（{{lang|en|Godfrey Newbold Hounsfield}}）。亨氏單位常用於X射線電腦斷層掃描，因此又稱為'''CT值'''（{{lang|en|CT number}}）。

== 定義 ==
亨氏單位為其所測量之介質的[[衰減係數#線性衰減係數|線性衰減係數]]的[[線性映射]]，其定義將[[蒸餾水]]與[[空氣]]在[[標準狀況|標準溫度與標準壓力]]下的{{le|阻射率|Radiodensity}}分別設為0 HU和-1,000 HU。因此，在[[衰減係數#線性衰減係數|線性衰減係數]]介於平均值間的[[體素]]中，其亨氏單位為：<ref>{{Cite web|title=CT Angiography and CT Perfusion Imaging|url=https://www.sciencedirect.com/topics/medicine-and-dentistry/hounsfield-scale|first1=Michael|last1=Lev|first2=Rodolfo|last2=Gonzalez|year=2002|access-date=2020-12-20|website=[[ScienceDirect]]|language=en|archive-date=2020-11-12|archive-url=https://web.archive.org/web/20201112021732/https://www.sciencedirect.com/topics/medicine-and-dentistry/hounsfield-scale|dead-url=no}}</ref>

<math>HU = 1000\times\frac{\mu - \mu_{\textrm{water}}}{\mu_{\textrm{water}} - \mu_{\textrm{air}}}</math>

其中<math>\mu_{\textrm{water}}</math>與<math>\mu_{\textrm{air}}</math>分別為[[水]]與[[空氣]]的[[衰減係數#線性衰減係數|線性衰減係數]]。<ref name="NIH HU">{{Cite web|title=Hounsfield Unit|url=https://www.ncbi.nlm.nih.gov/books/NBK547721/|first1=Tami|last1=DenOtter|first2=Johanna|last2=Schubert|date=2020-05-11|access-date=2020-12-20|website=[[國家衛生院 (美國)|美國國家衛生院]]|language=en|archive-date=2021-12-06|archive-url=https://web.archive.org/web/20211206115044/https://www.ncbi.nlm.nih.gov/books/NBK547721/|dead-url=no}}</ref>

由於空氣的線性衰減係數趨近於0，一個HU的變化相當於水[[衰減係數#線性衰減係數|線性衰減係數]]0.1%的變化。<ref name="NIH HU" />

=== 原理 ===
由於[[X射線電腦斷層掃描]]的功能在於將生物（主要是陸上生物，如[[人|人類]]）的體內結構成像化，因此採納上述標準作為所有介質的參照依據。<ref name="NIH HU" />

== 人體內各介質的亨氏單位值 ==
亨氏單位僅適用於常見的雙能[[電腦斷層掃描]]（dual-energy CT scan），而不適用於[[錐狀射束電腦斷層掃描]]（cone beam CT scan）。<ref name="DEVOS">{{cite journal|last1=De Vos|first1=W.|last2=Casselman|first2=J.|last3=Swennen|first3=G.R.J.|title=Cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial region: A systematic review of the literature|journal=International Journal of Oral and Maxillofacial Surgery|date=2009-06|volume=38|issue=6|pages=609–625|doi=10.1016/j.ijom.2009.02.028|pmid=19464146}}</ref>

{| class="wikitable"
|-
!colspan=2| 介質 !! 亨氏單位
|-
|colspan=2| [[空氣]]
| −1,000
|-
|colspan=2| [[脂肪]]
| −120至−90<ref name=Lepor2000/>
|-
| colspan=2| {{le|造影劑電腦斷層掃描|Contrast CT}}下的[[軟組織]]
| +100至+300
|-
|rowspan=2| [[骨骼]] || 鬆質骨 || +300至+400<ref name="BirurPatrick2017">{{cite journal|last1=Birur|first1=NPraveen|last2=Patrick|first2=Sanjana|last3=Gurushanth|first3=Keerthi|last4=Raghavan|first4=AShubhasini|last5=Gurudath|first5=Shubha|title=Comparison of gray values of cone-beam computed tomography with hounsfield units of multislice computed tomography: An in vitro study|journal=Indian Journal of Dental Research|volume=28|issue=1|year=2017年|pages=66–70|issn=0970-9290|doi=10.4103/ijdr.IJDR_415_16|pmid=28393820}}</ref>
|-
| [[密質骨]] || +1,800至+1,900<ref name="BirurPatrick2017"/>
|-
|rowspan=3| [[頭部外傷]] || 前數小時 || +75至+100<ref name="Rao2016">Fig 3 in: {{cite journal|last1=Rao|first1=Murali Gundu|title=Dating of Early Subdural Haematoma: A Correlative Clinico-Radiological Study|journal=Journal of Clinical and Diagnostic Research|volume=10|issue=4|pages=HC01–5|year=2016|issn=2249-782X|doi=10.7860/JCDR/2016/17207.7644|pmid=27190831|pmc=4866129}}</ref>
|-
| 3日後 || +65至+85<ref name="Rao2016"/>
|-
| 10-14日後 || +35至+40<ref>{{cite web|url=https://radiopaedia.org/articles/subdural-haemorrhage|author=Dr Rohit Sharma|author2=A.Prof Frank Gaillard|accessdate=2018-08-14|website=[[Radiopaedia]]|title=Subdural haemorrhage|archive-date=2011-03-23|archive-url=https://web.archive.org/web/20110323070116/https://radiopaedia.org/articles/subdural-haemorrhage|dead-url=no}}</ref>
|-
|rowspan=2| 其他[[血液]] || 非凝血 || +13<ref name=fosbinder2011>[https://books.google.com/books?id=jRVg5ilM1UEC&pg=PA263 Page 263] in: {{cite book|title=Essentials of Radiologic Science|url=https://archive.org/details/essentialsofradi0000fosb_u7d2|author=Robert Fosbinder|author2=Denise Orth|publisher=Lippincott Williams & Wilkins|year=2011|isbn=9780781775540}}</ref>至+50<ref>[https://books.google.com/books?id=Bif0zpmEWtAC&pg=SA20-PA17 page 20.17] in: {{cite book|title=Radiology of the Chest and Related Conditions|author=F W Wright|publisher=CRC Press|year=2001|isbn=9780415281416}}</ref>
|-
| [[凝血]] || +50<ref name=fast2006>[https://books.google.com/books?id=4HaPJYaXXSAC&pg=PA17 page 17] in: {{cite book|title=Navigating the Adult Spine: Bridging Clinical Practice and Neuroradiology|author=Dr. Avital Fast|author2=Dorith Goldsher|publisher=Demos Medical Publishing|year=2006|isbn=9781934559741}}</ref>至+75<ref name=fosbinder2011/><ref name=fast2006/>
|-
|rowspan=2| [[胸腔積液]] || {{le|漏出液|Transudate}} || +2至+15 <ref name="CulluKalemci2013">{{cite journal|last1=Cullu|first1=Nesat|last2=Kalemci|first2=Serdar|last3=Karakas|first3=Omer|last4=Eser|first4=Irfan|last5=Yalcin|first5=Funda|last6=Boyaci|first6=Fatma Nurefsan|last7=Karakas|first7=Ekrem|title=Efficacy of CT in diagnosis of transudates and exudates in patients with pleural effusion|journal=Diagnostic and Interventional Radiology|volume=20|issue=2|pages=116–20|year=2013|issn=1305-3825|doi=10.5152/dir.2013.13066|pmid=24100060|pmc=4463296}}</ref> 
|-
| [[滲出液]] || +4至+33<ref name="CulluKalemci2013"/>
|-
|rowspan=7| 其他體液 || [[乳糜]]
| −30<ref>[https://books.google.com/books?id=QmLNBQAAQBAJ&pg=PA342 Page 342] in: {{cite book|title=Multi-Detector CT Imaging: Principles, Head, Neck, and Vascular Systems, Volume 1|author=Luca Saba|author2=Jasjit S. Suri|publisher=CRC Press|year=2013|isbn=9781439893845}}</ref>
|-
| [[水]]
| 0
|-
| [[尿|尿液]]
| −5至+15<ref name=Lepor2000>Page 83 in: {{cite book|title=Prostatic Diseases|url=https://archive.org/details/prostaticdisease0000unse|author=Herbert Lepor|publisher=W.B. Saunders Company|year=2000|isbn=9780721674162}}</ref>
|-
| [[膽汁]]
| −5至+15<ref name=Lepor2000/>
|-
|[[腦脊液]]
| +15
|-
| [[膿瘍]]/[[膿]]
| 0<ref name=ecr>{{cite journal|url=http://pdf.posterng.netkey.at/download/index.php?module=get_pdf_by_id&poster_id=119826|title=Liver abscesses: where do they come from?A review of the main types of liver abscesses and the correlation between their causes and the radiologic findings|author=P. Sanchez de Medina Alba|author2=C. Santos Montón|author3=N. Calvo|author4=K. El Karzazi|author5=T. González de la Huebra Labrador|author6=R. Corrales|author7=N. Alegre Borge|author8=Salamanca/ES.|doi=10.1594/ecr2014/C-1927|website=ECR 2014|year=2014|access-date=2020-12-17|archive-date=2019-01-12|archive-url=https://web.archive.org/web/20190112195058/http://pdf.posterng.netkey.at/download/index.php?module=get_pdf_by_id&poster_id=119826|dead-url=no}}</ref>至+20<ref name="SasakiMiyata2014">{{cite journal|last1=Sasaki|first1=Toru|last2=Miyata|first2=Rie|last3=Hatai|first3=Yoshiho|last4=Makita|first4=Kohzoh|last5=Tsunoda|first5=Koichi|title=Hounsfield unit values of retropharyngeal abscess-like lesions seen in Kawasaki disease|journal=Acta Oto-Laryngologica|volume=134|issue=4|year=2014|pages=437–440|issn=0001-6489|doi=10.3109/00016489.2013.878475|pmid=24512428}}</ref> 或 +40<ref name="SasakiMiyata2014"/>至+45<ref name=ecr/>
|-
| [[黏液]]
| 0<ref>{{Cite journal|url=http://medind.nic.in/ibn/t06/i2/ibnt06i2p191.pdf|title=Mucocoele Of The Appendix|author=K SAGGAR, A AHLUWALIA|author2=P SANDHU, V KALIA|journal=Ind J Radiol Imag|year=2006|volume=16|issue=2}}{{Dead link}}</ref> - 130<ref name="GaetaVinci2001">{{cite journal|last1=Gaeta|first1=Michele|last2=Vinci|first2=Sergio|last3=Minutoli|first3=Fabio|last4=Mazziotti|first4=Silvio|last5=Ascenti|first5=Giorgio|last6=Salamone|first6=Ignazio|last7=Lamberto|first7=Salvatore|last8=Blandino|first8=Alfredo|title=CT and MRI findings of mucin-containing tumors and pseudotumors of the thorax: pictorial review|journal=European Radiology|volume=12|issue=1|year=2001|pages=181–189|issn=0938-7994|doi=10.1007/s003300100934|pmid=11868096}}</ref>（超過70HU時進入高衰減）<ref>{{cite journal|title=High-Attenuation Mucus Impaction in Patients With Allergic Bronchopulmonary Aspergillosis: Objective Criteria on High-Resolution Computed Tomography and Correlation With Serologic Parameters|author=Subash S Phuyal|author2=Mandeep Kumar MK Garg|author3=Ritesh R Agarwal|author4=Pankaj P Gupta|author5=Arunaloke A Chakrabarti|author6=Manavjit Singh MS Sandhu|author7=Niranjan N Khandelwal|date=2015-09-02|journal=Current Problems in Diagnostic Radiology}}</ref><ref name="AgarwalSehgal2016">{{cite journal|last1=Agarwal|first1=Ritesh|last2=Sehgal|first2=Inderpaul Singh|last3=Dhooria|first3=Sahajal|last4=Aggarwal|first4=Ashutosh|title=Radiologic Criteria for the Diagnosis of High-Attenuation Mucus in Allergic Bronchopulmonary Aspergillosis|journal=Chest|volume=149|issue=4|year=2016|pages=1109–1110|issn=0012-3692|doi=10.1016/j.chest.2015.12.043|pmid=27055707}}</ref>
|-
|rowspan=9| [[薄壁組織]] || [[肺]]
| −700至−600<ref>[https://books.google.com/books?id=IJwZHPrDQYUC&pg=PA379 Page 379] in: {{cite book|title=Cardiopulmonary Imaging|volume=4|author=Ella A. Kazerooni|author2=Barry H. Gross|publisher=Lippincott Williams & Wilkins|year=2004|isbn=9780781736558}}</ref>
|-
| [[腎]]
| +20至+45<ref name=Lepor2000/>
|-
| [[肝]]
| 60 ± 6<ref>[https://books.google.com/books?id=62jMOh67D8UC&pg=PA210 page 210] in: {{cite book|title=Hepatology, Principles and Practice: History, Morphology, Biochemistry, Diagnostics, Clinic, Therapy|author=Erwin Kuntz|author2=Hans-Dieter Kuntz|publisher=Springer Science & Business Media|year=2006|isbn=9783540289777}}</ref>
|-
| [[淋巴結]]
| +10至+20<ref>[https://books.google.com/books?id=mfYkBAAAQBAJ&pg=PA58 Page 58] in: {{cite book|title=High-Resolution Computed Tomography of the Paranasal Sinuses and Pharynx and Related Regions: Impact of CT identification on diagnosis and patient management. Volume 12 of Series in Radiology|author=G. Maatman|publisher=Springer Science & Business Media|year=2012|isbn=9789400942776}}</ref>
|-
| [[肌肉]]
| +35至+55<ref name=Lepor2000/>
|-
|rowspan=2| [[胸腺]]
| +20至+40（兒童）<ref name=givel2012>[https://books.google.se/books?id=AsTcBQAAQBAJ&pg=PT488 Page 488] {{Wayback|url=https://books.google.se/books?id=AsTcBQAAQBAJ&pg=PT488 |date=20171025022335 }} in: {{cite book|title=Surgery of the Thymus: Pathology, Associated Disorders and Surgical Technique|author=Jean-Claude Givel|author2=Marco Merlini|author3=David B. Clarke|author4=Michael Dusmet|publisher=Springer Science & Business Media|year=2012|isbn=9783642710766}}</ref>
|-
| +20至+120（成人）<ref name=givel2012/>
|-
|[[白質]]
| +20至+30
|-
|[[灰質]]
| +37至+45
|-
|rowspan=2| [[膽結石]] || 膽固醇石 || +30至+100<ref name="pmid2121509">{{cite journal|vauthors=Rambow A, Staritz M, Wosiewitz U, Mildenburger P, Thelen M, Meyer zum Büschenfelde KH| title=Analysis of radiolucent gallstones by computed tomography for in vivo estimation of stone components |url=https://archive.org/details/sim_european-journal-of-clinical-investigation_1990-08_20_4/page/475| journal=Eur J Clin Invest | year= 1990 | volume= 20 | issue= 4 | pages= 475–8 | pmid=2121509 | doi= 10.1111/j.1365-2362.1990.tb01887.x}}</ref>
|-
| 色素性膽結石 || +90至+120<ref name="pmid2121509"/>
|-
|rowspan=7| {{le|異物|Foreign body}}<ref name="BolligerOesterhelweg2009">{{cite journal|last1=Bolliger|first1=Stephan A.|last2=Oesterhelweg|first2=Lars|last3=Spendlove|first3=Danny|last4=Ross|first4=Steffen|last5=Thali|first5=Michael J.|title=Is Differentiation of Frequently Encountered Foreign Bodies in Corpses Possible by Hounsfield Density Measurement?|url=https://archive.org/details/sim_journal-of-forensic-sciences_2009-09_54_5/page/1119|journal=Journal of Forensic Sciences|volume=54|issue=5|year=2009|pages=1119–1122|issn=0022-1198|doi=10.1111/j.1556-4029.2009.01100.x|pmid=19627414}}</ref> 
|| 一般窗戶玻璃 || +500
|-
| [[鋁]]、[[瀝青]]、車窗玻璃、玻璃瓶與其他石類 || +2,100至+2,300
|-
| [[石灰岩]] || +2,800
|-
| [[銅]] || +14,000
|-
| [[銀]] || +17,000
|-
| [[鋼]] || +20,000
|-
| [[金]]、[[鋼]]與[[黃銅]] || +30,000（可測量之上限）
|-
|colspan=2| [[耳垢]] || <0
|}

亨氏單位常用於辨識[[腫瘤]]，以{{le|腎上腺腺瘤|Adrenal adenoma}}為例，當該腫瘤的{{le|阻射率|Radiodensity}}小於10 HU，則其脂肪成分偏高，代表該腫瘤有較大機率為[[良性腫瘤]]<ref>{{Cite web |title=Adrenal Adenoma Imaging |url=http://emedicine.medscape.com/article/376240 |accessdate=2020-12-19 |author=Perry J Horwich |date=2011-04-21 |language=en}}</ref>。

== 參見 ==

=== 參考資料 ===
{{reflist|30em}}

=== 參考書籍 ===
*{{cite book
|last=Feeman
|first=Timothy G.
|title=The Mathematics of Medical Imaging: A Beginner's Guide
|series=Springer Undergraduate Texts in Mathematics and Technology
|publisher=Springer
|year=2010
|isbn=978-0387927114
}}

== 外部連結 ==
*{{cite web|url=http://www.medcyclopaedia.com/library/topics/volume_i/h/hounsfield_unit.aspx|archive-url=https://archive.today/20120404030558/http://www.medcyclopaedia.com/library/topics/volume_i/h/hounsfield_unit.aspx|dead-url=yes|archive-date=2012-04-04|title=Hounsfield unit|publisher=[[General Electric|GE]]|website=Medcyclopaedia|accessdate=2020-12-17}}
*[http://www.fpnotebook.com/Rad/CT/HnsfldUnt.htm Hounsfield Unit] {{Wayback|url=http://www.fpnotebook.com/Rad/CT/HnsfldUnt.htm |date=20201224182323 }} - fpnotebook.com
*{{cite web|url=http://www.intl.elsevierhealth.com/e-books/pdf/940.pdf|title=Introduction to CT physics|publisher=elsevierhealth.com|archive-url=https://web.archive.org/web/20070926231241/http://www.intl.elsevierhealth.com/e-books/pdf/940.pdf|archive-date=2007-09-26|accessdate=2020-12-17|dead-url=no}}
* [https://www.researchgate.net/publication/24234798_Imaging_of_deep_brain_stimulation_leads_using_extended_Hounsfield_unit_CT Imaging of deep brain stimulation leads using extended Hounsfield unit CT. Stereotact Funct Neurosurg. 2009;87(3):155-60. doi: 10.1159/000209296] {{Wayback|url=https://www.researchgate.net/publication/24234798_Imaging_of_deep_brain_stimulation_leads_using_extended_Hounsfield_unit_CT |date=20160303224536 }}

[[Category:放射線學]]