Determination of Absorbed Radiation Dose Levels of Lenses Thyroid and Oral Mucosa in Computed Tomography Imagining: Phantom Study

Abstract

Objective: Head-neck computed tomography (CT) imaging is one of the most common tomography examinations in medical imaging. Lenses and thyroid are among the most sensitive organs to radiation. The aim of this study was to determine the radiation dose levels to which the patient's lens, oral mucosa, and thyroid were during head and neck CT imaging.

Methods: Thyroid, oral mucosa and lens areas of human equivalent Alderson rando phantom were placed in thermoluminescence dosimeter (TLD) dosimeters and computerized tomography imaging of head-neck of phantom was performed in this study. A total of 18 TLD dosimetry was used in this study. Firstly, dosimeters were calibrated. 6 of these dosimeters were placed on the thyroid of the phantom and 4 of them were placed in the mouth and 4 of them were in the lens. 4 dosimeters were used for background measurements

Results: The radiation dose in TLDs placed at the center of the lens was between 15.03 and 23.71 mSv (mean 19.83±3.93 mSv), the oral mucosa was 10.36 to 19.47 mSv (mean 15.15±2.96 mSv), and the thyroid gland was between 11.21 and 16.73 mSv (mean 13.97±3.90 mSv).

Conclusion: The permissible radiation dose for whole body and eye lenses in ICRP reports is 20 mSv/year for radiation officers. Likewise, there is no definite limit for patients, it is aimed to keep the dose level to a minimum. Therefore, knowing the reference dose is important for imaging planning.

Keywords

• radiation dose,thyroid,lens,computed tomography,Thermoluminescence dosimeter

Bilgisayarlı Tomografi Çekimlerinde Lens Tiroid ve Oral Mukoza Absorbe Radyasyon Doz Düzeylerinin Belirlenmesi: Fantom Çalışması

Abstract

Amaç: Baş ve boyun bilgisayarlı tomografi (BT) görüntülemesi, en sık kullanılan radyolojik incelemelerinden biridir. Birçok hastalığın tanısında önemli rol oynar. Lens ve tiroid bezi radyasyona karşı en duyarlı organlardandır. Bu çalışmanın amacı, BT görüntülemesi yapılan hastaların, lens, oral mukoza ve tiroid dokusunun maruz kaldığı radyasyon dozunun belirlenmesidir.

Yöntem: Çalışmada, insan eşdeğeri olan Alderson Rando fantomunun tiroid, oral mukoza, lens bölgelerine termolüminesans dozimetreleri (TLD) yerleştirilmiş ve fantomun baş-boyun bölgesinin BT görüntülemesi yapılmıştır. Toplam 18 adet TLD kullanılmıştır. Öncelikle dozimetrelerin kalibrasyon işlemleri yapılmıştır. Bu dozimetrelerden 6 tanesi fantomun tiroid bölgesine, 4 tanesi oral mukozaya, 4 tanesi de lens bölgesine yerleştirilmiştir. 4 tane dozimetre ise arkaplan (background) ölçümleri için kullanılmıştır.

Bulgular: Lens merkezine yerleştirilen TLD’lerdeki radyasyon dozu 15,03 ile 23,71 mSv arasında (ortalama 19,83±3,93 mSv), oral mukozada 10,36 ile 19,47 mSv arasında (ortalama 15,15±2,96 mSv), tiroid bezinde ise 11,21 ile 16,73 mSv arasında (ortalama 13,97±3,90 mSv) bulunmuştur.

Sonuç: Uluslararası Radyolojik Koruma Komisyonu (ICRP)raporlarında tüm vücut ve lensler için müsaade edilen radyasyon dozu, radyasyon görevlilerinde 20 mSv/yıl’dır. Hastalar için kesin bir limit olmamakla beraber, doz düzeyinin minimum tutulması amaçlanır. Bu nedenle referans dozunun bilinmesi çekim planlaması için önemlidir.

Keywords

• radyasyon dozu,göz,tiroid,bilgisayarlı tomografi,Termolüminesans dozimetreleri

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