Xaunsfild shkalasi

Vikipediya, ochiq ensiklopediya

Xaunsfild shkalasi ( /ˈhnzfld/ HOWNZ-feeld ), ser Godfrey Xaunsfild nomi bilan atalgan, radiozichlikni tavsiflovchi miqdoriy o'lchovdir. Ko'pincha kompyuter tomografiyasida qo'llaniladi va uning qiymati KT raqami deb ham ataladi.

Ta'rif[tahrir | manbasini tahrirlash]

Xaunsfild birligi (HB) shkalasi standart bosim va haroratda ( STP ) distillangan suvning radiozichligi 0 Hounsfild birligi (HB), havoning radiozichligi esa STP da -1000 HB sifatida aniqlanuvchi chiziqli so'nish koeffitsientini o'lchashning chiziqli o'zgarishi hisoblanadi. O'rtacha chiziqli so'nish koeffitsienti vokselda , shuning uchun tegishli HB qiymati quyidagicha aniqlanadi:

bu yerda va mos ravishda suv va havoning chiziqli suysayish koeffitsientlari.

Shunday qilib, bir Xaunsfild birligining (HB) o'zgarishi suvning so'nish koeffitsientining 0,1% o'zgarishini anglatadi, chunki havoning zaiflashuv koeffitsienti deyarli nolga teng.[1] :259

Standartlashtirilgan javobni ta'minlash uchun suv va boshqa materiallarga nisbatan HB kalibrlash sinovlari amalga oshirilishi mumkin. Bu, ayniqsa, HB elektron zichligiga aylantiriladigan radioterapiyada davolashni rejalashtirishda foydalaniladigan KT tekshiruvi uchun juda muhimdir.[2] Tarkibi ma'lum bo'lgan etalon materiallarining o'lchangan qiymatlarining o'zgarishi va bo'laklar orasidagi va ichidagi o'zgarishlar sinov jarayonlarining bir qismi sifatida foydalanishi mumkin.[1] :283[3]

Asosiy sabab[tahrir | manbasini tahrirlash]

Yuqoridagi standartlar universal ma'lumotnomalar bo'lgani uchun tanlangan va kompyuterli eksenel tomografiya ishlab chiqilgan asosiy dasturga mos keladi: uyushgan suv tuzilmalariga asoslangan va asosan havoda yashovchi tirik mavjudotlarning ichki anatomiyasini tasvirlash, masalan, odamlar .

Вышеупомянутые стандарты были выбраны, поскольку они являются общедоступными эталонами и подходят для ключевого приложения, для которого была разработана компьютерная аксиальная томография: визуализация внутренней анатомии живых существ, основанных на организованных водных структурах и в основном живущих в воздухе, т.е. люди.

Turli tana to'qimalari va materiallar uchun qiymatlari[tahrir | manbasini tahrirlash]

Oyna darajasi -700 HU (o'pka) ga o'rnatilgan ko'krak qafasining kompyuter tomografiyasi
Oyna darajasi -1000 HU (havo) ga o'rnatilgan ko'krak qafasining kompyuter tomografiyasi
Oyna darajasi 0 HU (suv) ga o'rnatilgan ko'krak qafasining kompyuter tomografiyasi
Oyna darajasi 60 HU (jigar) ga o'rnatilgan ko'krak qafasining kompyuter tomografiyasi

Materialning HU-ga asoslangan differentsiatsiyasi tibbiy darajadagi ikki energiyali KT skanerlari uchun qo'llaniladi, lekin konus nurli kompyuter tomografiyasi (CBCT) skanerlari uchun emas, chunki CBCT skanerlari ishonchsiz HU ko'rsatkichlarini beradi.[4]

Дифференциация материала на основе HU применяется к двухэнергетическим КТ медицинского уровня, но не к сканам конусно-лучевой компьютерной томографии (КЛКТ), поскольку сканирование КЛКТ дает ненадежные показания HU.

Bu yerda bildirilgan qiymatlar taxminiydir. Bir tadqiqotdan boshqasiga turli dinamikalar haqida xabar beriladi.

Aniq HB dinamikasi KTni olish va qayta qurish parametrlari (kV, filtrlar, rekonstruksiya algoritmlari va boshqalar) tufayli bir KT olishdan boshqasiga o'zgarishi mumkin. Kontrastli vositalardan foydalanish tananing ba'zi qismlarida (asosan qon) ham HB ni o'zgartiradi.

Modda HU
Havo −1000
Yog ' −120 dan −90 gacha[5]
Kontrastli KTda yumshoq to'qimalar +100 dan +300 gacha
Suyak Bo'lakchalari +300 dan +400 gacha[6]
Kortikal +500 dan +1900 gacha[7][6][8]
Subdural gematoma Birinchi soatlar +75 dan +100 gacha[9]
3 kundan keyin +65 dan +85 gacha[9]
10-14 kundan keyin +35 dan +40 gacha[10]
Boshqa qon Ivimagan qon +13[11] dan +50[12] gacha
Ivigan +50[13] dan +75[11][13] gacha
Plevra oqishi Transudat +2 dan +15 gacha[14]
Eksudat +4 dan +33 gacha[14]
Boshqa suyuqliklar sutli tana suyuqligi −30[15]
Suv 0
Siydik −5 dan +15 gacha[5]
Safro −5 dan +15 gacha[5]
Orqa miya suyuqligi +15
Absses / yiring 0[16] yoki +20,[17] dan +40[17] yoki +45[16] gacha
Shilliq 0[18] - 130[19] (70 HU dan ortiq "yuqori zaiflashuv")[20][21]
Parenxima O'pka −700 dan −600 gacha[22]
Buyrak +20 dan +45 gacha[5]
Jigar 60 ± 6[23]
Limfa tugunlari +10 dan +20 gacha[24]
Muskul +35 dan +55 gacha[5]
Timus
  • Bolalarda +20 dan +40 gacha[25]
  • O'smirlarda +20 dan +120 gacha[25]
Oq modda +20 dan +30 gacha
Kulrang modda +37 dan +45 gacha
O't toshlari Xolesterin tosh +30 dan +100 gacha[26]
Bilirubin tosh +90 dan +120 gacha[26]
Boshqa jismlar[27] Deraza oynasi +500
Alyuminiy, asfalt, avtomobil oynasi oynasi, shisha oynasi va boshqa jinslar +2100 dan +2300 gacha
Ohaktosh +2800
Mis +14 000
Kumush +17 000
Po'lat +20 000
Oltin, po'lat va guruch +30 000 (yuqori o'lchanadigan chegara)
Quloq mumi <0

Buning amaliy jihatdan o'smalarni baholashda qo'llaniladi, masalan, radiozichligi 10 HB dan kam radiozichlikka ega bo'lgan buyrak usti o'simtasi ko'proq yog'li tarkibga ega va deyarli shubhasiz yaxshi hosilali adenomadir .[28]


Ushbu tarjima O'zbekiston Millliy Universiteti Fizika fakulteti talabasi Ikbalova Muxlisaxon tomonidan qilindi.

Yana qarang[tahrir | manbasini tahrirlash]

Foydalanilgan dabaiyotlar ro'yxati[tahrir | manbasini tahrirlash]

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  2. Radiation oncology physics: a handbook for teachers and students.. Vienna: International Atomic Energy Agency, 2005 — 230 bet. ISBN 92-0-107304-6. 
  3. Samei, Ehsan. AAPM Report No. 233: Performance Evaluation of Computed Tomography Systems - The Report of AAPM Task Group 233. Alexandria, VA: American Association of Physicists in Medicine, 2019. DOI:10.37206/186. ISBN 978-1-936366-69-9. 
  4. De Vos, W.; Casselman, J.; Swennen, G.R.J. (June 2009). "Cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial region: A systematic review of the literature". International Journal of Oral and Maxillofacial Surgery 38 (6): 609–625. doi:10.1016/j.ijom.2009.02.028. PMID 19464146. 
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  7. Lim Fat, Daren; Kennedy, Jim; Galvin, Rose; O’Brien, Fergal; Mc Grath, Frank; Mullett, Hannan (2012-05-01). "The Hounsfield value for cortical bone geometry in the proximal humerus—an in vitro study" (en). Skeletal Radiology 41 (5): 557–568. doi:10.1007/s00256-011-1255-7. ISSN 1432-2161. PMID 21932054. https://doi.org/10.1007/s00256-011-1255-7. 
  8. Aamodt, A.; Kvistad, K. A.; Andersen, E.; Lund-Larsen, J.; Eine, J.; Benum, P.; Husby, O. S. (January 1999). "Determination of Hounsfield value for CT-based design of custom femoral stems". The Journal of Bone and Joint Surgery. British Volume 81 (1): 143–147. doi:10.1302/0301-620X.81B1.0810143. ISSN 0301-620X. PMID 10068022. https://pubmed.ncbi.nlm.nih.gov/10068022. 
  9. 9,0 9,1 Fig 3 in: Rao, Murali Gundu (2016). "Dating of Early Subdural Haematoma: A Correlative Clinico-Radiological Study". Journal of Clinical and Diagnostic Research 10 (4): HC01–5. doi:10.7860/JCDR/2016/17207.7644. ISSN 2249-782X. PMID 27190831. PMC 4866129. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4866129. 
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  14. 14,0 14,1 Cullu, Nesat; Kalemci, Serdar; Karakas, Omer; Eser, Irfan; Yalcin, Funda; Boyaci, Fatma Nurefsan; Karakas, Ekrem (2013). "Efficacy of CT in diagnosis of transudates and exudates in patients with pleural effusion". Diagnostic and Interventional Radiology 20 (2): 116–20. doi:10.5152/dir.2013.13066. ISSN 1305-3825. PMID 24100060. PMC 4463296. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4463296. 
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  16. 16,0 16,1 P. Sanchez de Medina Alba; C. Santos Montón; N. Calvo; K. El Karzazi; T. González de la Huebra Labrador; R. Corrales; N. Alegre Borge; Salamanca/ES. (2014). 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. doi:10.1594/ecr2014/C-1927. Archived from the original on 2019-01-12. https://web.archive.org/web/20190112195058/http://pdf.posterng.netkey.at/download/index.php?module=get_pdf_by_id&poster_id=119826. Qaraldi: 2023-06-07. Xaunsfild shkalasi]]
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  20. Subash S Phuyal; Mandeep Kumar MK Garg; Ritesh R Agarwal; Pankaj P Gupta; Arunaloke A Chakrabarti; Manavjit Singh MS Sandhu; Niranjan N Khandelwal (2015-09-02). "High-Attenuation Mucus Impaction in Patients With Allergic Bronchopulmonary Aspergillosis: Objective Criteria on High-Resolution Computed Tomography and Correlation With Serologic Parameters". Current Problems in Diagnostic Radiology. 
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  23. page 210 in: Erwin Kuntz. Hepatology, Principles and Practice: History, Morphology, Biochemistry, Diagnostics, Clinic, Therapy. Springer Science & Business Media, 2006. ISBN 9783540289777. 
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  25. 25,0 25,1 Page 488 in: Jean-Claude Givel. Surgery of the Thymus: Pathology, Associated Disorders and Surgical Technique. Springer Science & Business Media, 2012. ISBN 9783642710766. 
  26. 26,0 26,1 "Analysis of radiolucent gallstones by computed tomography for in vivo estimation of stone components". Eur J Clin Invest 20 (4): 475–8. 1990. doi:10.1111/j.1365-2362.1990.tb01887.x. PMID 2121509. https://archive.org/details/sim_european-journal-of-clinical-investigation_1990-08_20_4/page/n140. 
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  28. medscape >Adrenal Adenoma Imaging. Author: Perry J Horwich. Chief Editor: Eugene C Lin. Updated: Apr 21, 2011

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