Toraks bilgisayarlı tomografi tetkiklerinin radyasyon dozları ve dozla ilişkili faktörlerin değerlendirilmesi
Küçük Resim Yok
Dosyalar
Tarih
2022
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Ege Üniversitesi, Tıp Fakültesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
GİRİŞ AMAÇ Bilgisayarlı Tomografi (BT) görüntüleme, kullanımı her geçen gün artmaktadır. BT görüntülemenin en önemli sorunlarından biri radyasyon dozu ve yönetimidir. Çalışmamızda Toraks BT görüntülemede hastaların maruz kaldığı ortalama radyasyon dozunu belirlemeyi ve radyasyon dozunu etkileyen faktörleri incelemeyerek optimize etmeyi amaçladık. GEREÇ VE YÖNTEM Çalışmamızda Ege Üniversitesi Tıp Fakültesi Hastanesi Radyoloji Anabilim Dalı’nda 1 Eylül 2021- 1 Aralık 2021 tarihleri arasında elde olunan toplam 1451 adet toraks anjio BT, dual enerji toraks anjio BT ve HRCT tetkiklerini retrospektif olarak inceledik. Çalışmada hastaların yaşı, tetkikin çekim zamanı (mesai içi, mesai dışı), tomografi cihazının markası (GE Discovery, Siemens Somatom ve Toshiba Aquilion Prime) , hastaları tetkike yönlendiren birimler (Acil servis, yatan hasta, poliklinik) , hastaların görüntüleme sırasındaki pozisyonları ( kolların durumu, santralizasyon , tarama alanları) , toraksın ölçülen en geniş bölümündeki ön- arka ve sağ- sol çapları değerlendirilmiş değişkenlerdir. Ayrıca 2021 Kasım ayında birimimizde yapılmış olan BT çekimiyle ilgili teknisyen eğitimi ve tomografi cihazlarındaki teknik parametre optimizasyonu bağımlı değişken olarak değerlendirilmiştir. Tüm olguların Bilgisayarlı Tomografi Doz İndeksleri (CTDI), Doz Uzunluk Ürünü (DLP) değerleri kaydedilmiş ve efektif doz hesaplamaları yapılmıştır. BULGULAR Çalışmamıza 1451 tetkik dahil edilmiştir. Tüm tetkiklerin ortalama CTDIvol değeri 8,93 (±3,65) mGy, DLP değeri 324,33 (±133,71) mGy.cm ve efektif doz değeri ise 4,54 (±1,87) mSv olarak hesaplanmıştır. HRCT tetkiklerinde ortalama efektif radyasyon dozu 4.22 mSv, toraks anjio BT 4.42 mSv ve dual enerji toraks anjio BT tetkiklerinde 6.86 mSV hesaplanmıştır. Toraks anjio BT ve HRCT tetkikleri ile karşılaştırıldığında Dual enerji toraks anjio BT tetkikinin CTDIvol, DLP ve efektif radyasyon doz değerlerinin istatistiksel anlamlı oranda yüksektir (p<0,05). Cinsiyet, yaş ve tetkikin elde olunduğu gün ile radyasyon doz parametreleri arasında anlamlı bir ilişki saptanmamıştır (p>0.005). Z-ekseninde toplam fazla taranmış alan fazlalığı ile ortalama DLP ve efektif doz değerleri arasında çok zayıf düzeyde pozitif yönde ilişki mevcuttur (sırasıyla p<0,01, r<0,2). Görüntüleme esnasında gantry içerisinde izomerkezde yerleşen olgularda, izomerkez yerleşimli olmayan olgulara göre ortalama CTDI vol değerlerinin istatistiksel olarak anlamlı düzeyde daha azdır (p<0,01). Tüm BT üniteleri göz önüne alındığında çekim esansında kolların konumu ile radyasyon dozu parametreleri arasında istatistiksel anlamlı fark bulunmamıştır (p>0.005). Toshiba Aquilion Prime BT ünitesinde elde olunan tetkiklerde kolların üstte durduğu tetkiklerde ortalama CTDIvol, DLP ve efektif radyasyon doz değerleri kolların yanda durduğu tetkiklere göre daha düşük olarak izlendi (p<0.005) Teknisyen eğitimi ve teknik parametre optimizasyonu öncesi dönemde 1044 tetkik elde olunmuştur sonraki dönemde ise 407 tetkik elde olunmuştur. Teknisyen eğitimi ve teknik parametre optimizasyon sonrası elde olunan tetkiklerde CTDIvol, DLP ve efektif doz ortalama değerleri düşüktür (p<0,01). Teknisyen eğitimi ve teknik parametre optimizasyonu sonrası elde olunan tetkiklerde arasında fazla taranan üst, alt ve toplam tarama alanı fazlalığı daha düşüktür. (p<0,01). Z-ekseninde alt kesimde tarama alanı tolerans mesafesi içerisinde olan olgularda DLP ve efektif radyasyon doz değerleri istatistiksel olarak anlamlı olarak düşüktür (p<0,01). SONUÇ Z-ekseninde gereksiz fazla tarama, çekim esnasında kolların gereksiz biçimde görüntüye dahil edilmesinin, hastaların gantry içerisinde izomerkez noktaya yerleştirilmemesi radyasyon dozunu arttırmaktadır. Teknisyen eğitimi ve teknik parametre optimizasyonu sonrası ortalama radyasyon dozu azalmaktadır ve yine eğitim sonrası olgular gantry içerisinde daha uygun pozisyonlanmaktadır. Etkin radyasyon dozu yönetimi hasta güvenliği için önemlidir ve radyoloji teknisyenleri, radyoloji doktorları ayrıca tüm hekimler tarafından göz önünde bulundurulmalıdır.
PURPOSE The use of Computed Tomography (CT) imaging is increasing day by day. One of the most important problems of CT imaging is radiation dose and management. In our study, we aimed to calculate the average radiation dose that patients were exposed to in thoracic CT imaging and to examine the factors affecting the radiation dose. MATERİALS AND METHODS In our study, we retrospectively analyzed a total of 1451 thoracic angio CT, dual energy thoracic angio CT and HRCT examinations obtained between 1 September 2021 and 1 December 2021 in the Department of Radiology at Ege University Medical Faculty Hospital. In the study, the age of the patients, the time of the examination (during working hours, out of working hours), the model of the tomography device (GE Discovery, Siemens Somatom ve Toshiba Aquilion Prime), the units refering the patients to the examination (emergency department, inpatient, outpatient clinic), the positions of the patients during image acquisition (arms status, centralization, scanning areas), anteroposterior and tranverse diameters in the widest measured part of the thorax are evaluated variables. In addition, technician training for CT acqusition was performed in our unit in November 2021 and the optimization of technical parameters in tomography devices were revised as dependent variables. Computed Tomography Dose Index (CTDI), Dose Length Product (DLP) values of all cases were recorded and effective dose calculations were made. RESULTS Our study population included 1451 patients. The mean CTDIvol value of all examinations was calculated as 8.93 (±3.65) mGy, the DLP value as 324.33 (±133.71) mGy.cm and the effective dose value as 4.54 (±1.87) mSv. The mean effective radiation dose was calculated as 4.22 mSv in HRCT examinations, 4.42 mSv in thoracic angio CT and 6.86 mSv in dual energy thoracic angio CT examinations. Compared with thoracic angio CT and HRCT examinations, CTDIvol, DLP and effective radiation dose values of Dual energy thoracic angio CT examinations were statistically significantly higher (p<0.05). No significant correlation was found between gender, age, the day of examination and radiation dose parameters (p>0.005). There was a very weak positive correlation between the total excess scanned area on the Z-axis and the mean DLP and effective dose values (p<0.01, r<0.2, respectively). During imaging, the mean CTDI vol values in the cases located in the isocenter within the gantry were statistically significantly lower than the cases located in the non-isocenter (p<0.01). Considering all CT units, no statistically significant difference was found between the position of the arms and the radiation dose parameters during the acquisition (p>0.005). In the examinations obtained in the Toshiba Aquilion Prime CT unit, the mean CTDIvol, DLP and effective radiation dose values were observed to be lower in the examinations with the arms on the upper side compared to the examinations with the arms at the side (p<0.005). In the period prior to technician training and technical parameter optimization, 1044 examinations were obtained and in the following period, 407 examinations were obtained. In the examinations obtained after technician training and technical parameter optimization, the mean values of CTDIvol, DLP and effective dose were lower (p<0.01). In the examinations obtained after technician training and technical parameter optimization, the excess scanned upper, lower and total scan area was lower. (p<0.01). DLP and effective radiation dose values were statistically significantly lower in cases whose scan area was within the tolerance range in the Z-axis (p<0.01). CONCLUSİON Unnecessary overscanning in the z axis, inclusion of the arms within image field of view during scanning and miscentering the patients in the gantry increases the radiation dose. After the technician training and technical parameter optimization, the average radiation dose decreases and the cases are positioned more appropriately in the gantry. Effective radiation does management is important for patient safety and must be priorized by by radiology technicians, radiologists and all physicians.
PURPOSE The use of Computed Tomography (CT) imaging is increasing day by day. One of the most important problems of CT imaging is radiation dose and management. In our study, we aimed to calculate the average radiation dose that patients were exposed to in thoracic CT imaging and to examine the factors affecting the radiation dose. MATERİALS AND METHODS In our study, we retrospectively analyzed a total of 1451 thoracic angio CT, dual energy thoracic angio CT and HRCT examinations obtained between 1 September 2021 and 1 December 2021 in the Department of Radiology at Ege University Medical Faculty Hospital. In the study, the age of the patients, the time of the examination (during working hours, out of working hours), the model of the tomography device (GE Discovery, Siemens Somatom ve Toshiba Aquilion Prime), the units refering the patients to the examination (emergency department, inpatient, outpatient clinic), the positions of the patients during image acquisition (arms status, centralization, scanning areas), anteroposterior and tranverse diameters in the widest measured part of the thorax are evaluated variables. In addition, technician training for CT acqusition was performed in our unit in November 2021 and the optimization of technical parameters in tomography devices were revised as dependent variables. Computed Tomography Dose Index (CTDI), Dose Length Product (DLP) values of all cases were recorded and effective dose calculations were made. RESULTS Our study population included 1451 patients. The mean CTDIvol value of all examinations was calculated as 8.93 (±3.65) mGy, the DLP value as 324.33 (±133.71) mGy.cm and the effective dose value as 4.54 (±1.87) mSv. The mean effective radiation dose was calculated as 4.22 mSv in HRCT examinations, 4.42 mSv in thoracic angio CT and 6.86 mSv in dual energy thoracic angio CT examinations. Compared with thoracic angio CT and HRCT examinations, CTDIvol, DLP and effective radiation dose values of Dual energy thoracic angio CT examinations were statistically significantly higher (p<0.05). No significant correlation was found between gender, age, the day of examination and radiation dose parameters (p>0.005). There was a very weak positive correlation between the total excess scanned area on the Z-axis and the mean DLP and effective dose values (p<0.01, r<0.2, respectively). During imaging, the mean CTDI vol values in the cases located in the isocenter within the gantry were statistically significantly lower than the cases located in the non-isocenter (p<0.01). Considering all CT units, no statistically significant difference was found between the position of the arms and the radiation dose parameters during the acquisition (p>0.005). In the examinations obtained in the Toshiba Aquilion Prime CT unit, the mean CTDIvol, DLP and effective radiation dose values were observed to be lower in the examinations with the arms on the upper side compared to the examinations with the arms at the side (p<0.005). In the period prior to technician training and technical parameter optimization, 1044 examinations were obtained and in the following period, 407 examinations were obtained. In the examinations obtained after technician training and technical parameter optimization, the mean values of CTDIvol, DLP and effective dose were lower (p<0.01). In the examinations obtained after technician training and technical parameter optimization, the excess scanned upper, lower and total scan area was lower. (p<0.01). DLP and effective radiation dose values were statistically significantly lower in cases whose scan area was within the tolerance range in the Z-axis (p<0.01). CONCLUSİON Unnecessary overscanning in the z axis, inclusion of the arms within image field of view during scanning and miscentering the patients in the gantry increases the radiation dose. After the technician training and technical parameter optimization, the average radiation dose decreases and the cases are positioned more appropriately in the gantry. Effective radiation does management is important for patient safety and must be priorized by by radiology technicians, radiologists and all physicians.
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