PrinciplesComputed tomography is co

Principles
Computed tomography is conducted by transmitting finely collimated x-ray beam through the body; the beam is received by an electronic detector as shown in (gambar). The scattered x-rays are lessened as a result of this collimation.
The subject is placed between the x-ray tube and the detector, and both are scanned synchronously in the direction of the arrows. Transvering the axial transverse cross section surface. The x-rays are narrowed to 2-3 mm in the direction of the scan, and to abaout 10 mm in a direction vertical to the scan, and are then measured by the detector. A one-dimensional distribution intensity profiele of projection of transmitted x-rays is obtained. After the first scan is completed. The x-ray tube and the detector are then rotated a given angle around the patient, and a profile of the second projection is obtained. The procedure is repeated over the range of 180(derajat). The x-ray detector consist of a scintillator and a photomultiplier.
A scintillator emits a weak light when it absorbs an x-ray photon, after which the light passes into a photocathode in photomultiplier. A pipe of Lucite for guiding the light is often placed between the photocathode and the scintillator to decrease the effect of non-uniformity of the surface of the photocathode, and become a current pulse by secondary electron multiplication of the photomultiplier. Hence the entry of an x-ray photon into the scintillstion counter result in the creation of an electic pulse, which is amplified and counted. As the amount of x-rays due to its high anatomic number. Xe is used as a multidetector because it facilitates the preparation of a small-volume ionization chamber.
These x-ray detector have a wider photon counting dynamic range than that of x-ray film. (gambar) shows the characteristic curves of film, and the output response sharacteristics of CT detectors. The intensity of incident x-ray is shown on the horizontal axis.
Although the x-ray intensity on film is zero, the optical density is not zero due to film fog. When the increased x-ray intensity falls within a certain range, the optical density becomes proportional to it the rises linearly. When the intensity is extremely large, the optical density becomes saturated and does not increase. The limits of the range of linearity are of a density of about 1:100. This is the “dynamic range” of the film. On the other hand, x-ray detector have a liniar response to x-ray intensity with a range of linearity of more than 1:10000. The dynamic range of the detector of a CT is required to be wide enough to cover the range of x-ray intensity from bone to air transmission in order to facilitate good density resolution. A block diagram of a CT unit is shown in (gambar). The x-ray beam emitted from the x-ray tube passes through the body, and the intensity of the transmitted x-ray is measure by the detector located opposite the x-ray tube. The intensity of incident x-ray is monitore by the reference detector at the same time, so that the change of x-ray output during radiography can be corrected. When the intensity of transmitted x-ray at a point of profile of projection is I, the incident intensity is I0, and the energy of the x-rays is assumed to be monochromatic.

Hasil (Bahasa Indonesia) 1:

Prinsip-prinsipDSA dilakukan oleh memancarkan sinar x-ray halus collimated melalui tubuh; balok ini diterima oleh detektor elektronik seperti yang ditunjukkan dalam (gambar). Sinar-x tersebar berkurang karena collimation ini.Subjek ditempatkan antara tabung x-ray dan detektor, dan keduanya dipindai serentak ke arah panah. Transvering permukaan penampang melintang aksial. Sinar-x dipersempit untuk 2-3 mm ke arah scan dan abaout 10 mm ke arah vertikal untuk pemindaian, dan kemudian diukur dengan detektor. Profiele intensitas distribusi dimensi proyeksi sinar-x ditransmisikan diperoleh. Setelah yang pertama scan selesai. Tabung sinar-x dan detektor yang kemudian diputar sudut tertentu di sekitar pasien, dan profil proyeksi kedua diperoleh. Prosedur ini diulang selama rentang 180(derajat). Detektor x-ray terdiri dari scintillator dan photomultiplier.A scintillator emits a weak light when it absorbs an x-ray photon, after which the light passes into a photocathode in photomultiplier. A pipe of Lucite for guiding the light is often placed between the photocathode and the scintillator to decrease the effect of non-uniformity of the surface of the photocathode, and become a current pulse by secondary electron multiplication of the photomultiplier. Hence the entry of an x-ray photon into the scintillstion counter result in the creation of an electic pulse, which is amplified and counted. As the amount of x-rays due to its high anatomic number. Xe is used as a multidetector because it facilitates the preparation of a small-volume ionization chamber.These x-ray detector have a wider photon counting dynamic range than that of x-ray film. (gambar) shows the characteristic curves of film, and the output response sharacteristics of CT detectors. The intensity of incident x-ray is shown on the horizontal axis.Although the x-ray intensity on film is zero, the optical density is not zero due to film fog. When the increased x-ray intensity falls within a certain range, the optical density becomes proportional to it the rises linearly. When the intensity is extremely large, the optical density becomes saturated and does not increase. The limits of the range of linearity are of a density of about 1:100. This is the “dynamic range” of the film. On the other hand, x-ray detector have a liniar response to x-ray intensity with a range of linearity of more than 1:10000. The dynamic range of the detector of a CT is required to be wide enough to cover the range of x-ray intensity from bone to air transmission in order to facilitate good density resolution. A block diagram of a CT unit is shown in (gambar). The x-ray beam emitted from the x-ray tube passes through the body, and the intensity of the transmitted x-ray is measure by the detector located opposite the x-ray tube. The intensity of incident x-ray is monitore by the reference detector at the same time, so that the change of x-ray output during radiography can be corrected. When the intensity of transmitted x-ray at a point of profile of projection is I, the incident intensity is I0, and the energy of the x-rays is assumed to be monochromatic.

Hasil (Bahasa Indonesia) 2:

Prinsip
Computed tomography dilakukan dengan mengirimkan berkas halus collimated x-ray melalui tubuh; balok diterima oleh detektor elektronik seperti pada (gambar). Sinar x-tersebar yang berkurang akibat collimation ini.
Subjek ditempatkan di antara tabung x-ray dan detektor, dan kedua-scan serentak ke arah panah. Transvering aksial transversal permukaan penampang. Sinar-x yang menyempit menjadi 2-3 mm ke arah scan, dan untuk abaout 10 mm dalam arah vertikal untuk scan, dan kemudian diukur dengan detektor. Sebuah distribusi satu dimensi intensitas profiele proyeksi sinar-x ditransmisikan diperoleh. Setelah scan pertama selesai. Tabung x-ray dan detektor kemudian diputar sudut tertentu di sekitar pasien, dan profil dari proyeksi kedua diperoleh. Prosedur ini diulang selama rentang 180 (derajat). Detektor x-ray terdiri dari sintilator dan photomultiplier.
Sebuah sintilator memancarkan cahaya lemah ketika menyerap foton x-ray, setelah cahaya melewati menjadi photocathode di photomultiplier. Sebuah pipa Lucite untuk membimbing cahaya sering ditempatkan antara photocathode dan sintilator untuk mengurangi efek non-keseragaman permukaan photocathode, dan menjadi pulsa saat ini dengan perkalian elektron sekunder photomultiplier. Oleh karena masuknya foton x-ray ke dalam scintillstion meja mengakibatkan penciptaan pulsa electic, yang diperkuat dan dihitung. Sebagai jumlah sinar-x karena jumlah anatomi yang tinggi. Xe digunakan sebagai multidetector karena memfasilitasi persiapan ionisasi volume kecil.
Ini detektor x-ray memiliki foton yang lebih luas menghitung rentang dinamis daripada film x-ray. (Gambar) menunjukkan kurva karakteristik film, dan sharacteristics respon output dari CT detektor. Intensitas insiden x-ray ditampilkan pada sumbu horisontal.
Meskipun intensitas x-ray pada film adalah nol, kepadatan optik tidak nol karena film kabut. Ketika intensitas x-ray peningkatan jatuh dalam kisaran tertentu, kepadatan optik menjadi sebanding dengan itu naik secara linier. Ketika intensitas sangat besar, kepadatan optik menjadi jenuh dan tidak meningkat. Batas-batas kisaran linearitas adalah dari kepadatan sekitar 1: 100. Ini adalah "dynamic range" dari film. Di sisi lain, detektor x-ray memiliki respon Linier intensitas x-ray dengan berbagai linearitas lebih dari 1: 10.000. Rentang dinamis detektor dari CT diperlukan untuk menjadi cukup lebar untuk mencakup rentang intensitas x-ray dari tulang untuk transmisi udara untuk memfasilitasi resolusi kepadatan yang baik. Diagram blok unit CT ditunjukkan pada (gambar). Sinar x-ray yang dipancarkan dari tabung x-ray melewati tubuh, dan intensitas x-ray yang ditransmisikan adalah ukuran oleh detektor terletak di seberang tabung x-ray. Intensitas insiden x-ray monitore oleh detektor referensi pada saat yang sama, sehingga perubahan output x-ray selama radiografi dapat diperbaiki. Ketika intensitas yang ditransmisikan x-ray pada titik profil dari proyeksi adalah saya, intensitas kejadian adalah I0, dan energi dari sinar-x diasumsikan monokromatik.