2. Kelengkapan Pesawat Sinar X Intervensional :
1. Control table
Pengaturan kondisis
expose
2. X Ray tube
Produksi X ray
3. Image Intensifier
Mengubah sinar x menjadi image
dan memerkuat image
4. Display screen
3. Basic X Ray intervensional positioning :
• Posisikan tube pada posisi yang terkecil radiasi hambur pada sekeliling area
radiasi
• Posisikan pasien sedekat mungkin II dengan sejauh mungkin sumber radisasi
• AOTRAUMA, 2011
4. X-ray tube position • AOTRAUMA, 2011
Staff exposed to increased radiation Staff exposed to reduced radiation
5. Absorption and scatter
• Dari 1000 photons x ray :
• ~20 : image detector
• ~100–200 : scattered
• ~ 800 : di absorbsi pasien
• Radiasi hambur meningkat, pada
posisi tube di samping
image
intensifier
x-ray tube
• AOTRAUMA, 2011
6. Pengaruh diameter Image Intensifier
terhadap dosis pada pasien (IAEA) :
Intensifier diameter Relative patient entrance
dose mSv/h
12’ (32 cm) Dose 100
9” (22 cm) Dose 150
6” (16 cm) Dose 200
4.5” (11 cm) Dose 300
Semakin kecil diameter image intensifier ,
semakin besar dosis pada pasien
9. Radiasi hambur dari beberapa konfigurasi peralatan. Daerah
isoexposure ditunjukkan dalam satuan millirad/jam.
A : fluoroskopi konvensional,
B : tabung sinarX di atas,
C : fluoroskopi Carm/ Uarm proyeksi posteroanterior,
D : fluoroskopi Carm/ Uarm proyeksi lateral.
11. Reduksi paparan radiasi hambur oleh permukaan (2,8 R/menit paparan pada kulit)
A: fluoroskopi vertikal tanpa perisai,
B: fluoroskopi oblique (450) tanpa perisai,
C: fluoroskopi vertikal dengan luas perisasi 25 x 15 cm (0,75 mm ekivalen Pb),
D: fluoroskopi oblique (450) dengan dilengkapi perisai.
14. Prinsip proteksi radiasi
Waktu
(semakin pendek waktu interaksi dengan radiasi,
semakin kecil kemungkinan terpapar radiasi)
Jarak
prinsip kuadrat jarak terbalik
(inverse square law)
Penahan radiasi (shielding)
18. Masalah yang lebih sering diperbincangkan
tentang dosis serap mata sebab risiko radiasi
yang dapat menyebabkan katarak. Efek biologi
timbul pada batas ambang tertentu,
apabila sekitar 600 rad diterima dari paparan
sinarX
diagnostik maka beberapa minggu
setelah kejadian akan mengakibatkan katarak
19. Katarak pada mata pekerja radiasi intervensional .
(Photograph from Vañó et al. (1998) ICRP 85.
20. Hasil pengukuran paparan radiasi
pesawat fluoroskopi (15 Mei 2011)
Hasil (µSv/jam)
Titik
Tempat Pengukuran Vertikal
Ukur 90 kV 50 mA
a Mata dokter 5
b Thyroid dokter 4
c Gonad dokter 2
d Gonad + apron dokter 0
e Mata asisten dokter 100
f Thyroid asisten dokter 98
g Gonad asisten dokter 76
h Gonad + apron asisten dokter 0
1 R. kontrol 0
2 Koridor A 0
3 Kamar dokter 0
4 Koridor B 0
R.
5 USG 0
21. Keamanan radiasi di ruang pemeriksaan intervensional :
Southport & Ormskirk Hospital, 2011
22.
23. UU 44 tahun 2009 tentang Rumah Sakit
Pasal 16 (1)
Persyaratan peralatan sebagaimana dimaksud dalam
Pasal 7 ayat (1) meliputi peralatan medis dan
nonmedis harus memenuhi standar pelayanan,
persyaratan mutu, keamanan, keselamatan dan laik
pakai.
Pasal 16 (2)
Peralatan medis sebagaimana dimaksud pada
ayat (1) harus diuji dan dikalibrasi secara berkala
oleh Balai Pengujian Fasilitas Kesehatan dan/atau
institusi pengujian fasilitas kesehatan yang
berwenang
24. Kesimpulan :
Posisikan tube pada bagian bawah meja
pemeriksaan
Tube harus diberi tambahan perisai radiasi
(shielding)
Ruang pemeriksaan sebaiknya diberi tambahan Lead
Glass Arm (kaca Pb dengan tangkai awal di pasang
pada plafon) yang mudah digerakkan
Selama bekerja dengan radiasi, Alat Pelindung Diri
dan Film / TLD Badge HARUS selalu digunakan
Sebelum dioperasikan, pesawat harus dilakukan uji
kesesuaian pesawat sinar x, sesuai UU No 44 tahun
2009 pasal 16 (2)
25. Daftar Pustaka
• National Council of Radiation Protection and Measurements: Basic Radiation
Protection Criteria. NCRP Report No. 39. Washington, DC, 1971
• National Council on Radiation Protection and Measurements: Medical X Ray and
Gamma Ray Protection for Energies up to 10 Mev. NCRP Report No. 33. Washington,
DC, 1968
• National Council on Radiation Protection and Measurements: Structural Shielding,
Design and Evaluation for Medical Use of Xrays of Energies up to 10 Mev. NCRP
Publication No. 49. Washington, DC, 1976
• Bushong SC: Radiologic Science for Technologists: Physics, Biology, and Protection. St.
Louis, CV Mosby, 1984
• Pizzarello DJ, Witcosfski RC: Medical Radiation Biology. Philadelphia, Lea & Febiger, 1982
• Marpaung, Togap, Proteksi Radiasi dalam Radiologi Intervensional, Seminar
Keselamatan Nuklir 2006
• www.AOTRAUMA.com, 2011
• Kepmenkes RI No 432/MENKES/SK/IV/2007 tentang Pedoman Manajemen Kesehatan
dan Keselamatan Kerja (K3) di Rumah Sakit
• UU No 44 tahun 2009 tentang Rumah Sakit
Not all x-rays pass through the object on which they are focussed. Some are reflected or refracted as they penetrate through an object, resulting in scatter. This scatter is potentially hazardous to surgical staff. Maximum scatter reflects from the side of the patient that is closest to the x-ray source. Therefore, the x-ray beam should be directed in such a way that the scatter is directed towards the floor. In practice, this means placing the x-ray beam under the patient. As the amount of scatter produced increases with the size of the area irradiated, it is desirable to restrict the field size to the area requiring imaging. The image intensifier screen should be kept as close as possible to the patient (as is practicable). This reduces scatter, improves image quality, and reduces radiation dose for the patient. In distal locking of IM nails the surgeon must be able to position the drill and drill bit between the image intensifier and the patient, and in this situation scatter is inevitable.
It is important to know the effect of the x-ray tube position. The cornea is the most vulnerable part of the body to radiation exposure (radiation cataracts). With a standard x-ray exposure, doubling the distance between the surgeon and the patient from 0.5 m to 1 m reduces exposure considerably. If the x-ray tube is positioned above the patient at a distance of 1 m (left), the surgeon’s/ORP’s eyes receive a dose of 2.2 milisieverts per hour (mSv/h). If the C-arm is turned and the x-ray tube is below the patient (right), the surgeon’s/ORP’s eyes will be exposed to just 55% of the scattered radiation, so 1.2mSv/h. Therefore, the x-ray tube position is of paramount importance.
The main source of radiation to the staff in the OR is scatter reflecting from the patient. Most of this is reflected back towards the x-ray source. Therefore in the lateral position, staff should be positioned behind the image intensifier side and NOT on the side of the x-ray source.
The smaller the diameter of the image intensifier the greater the entrance dose of radiation. Laser aiming devices on modern image intensifiers enable accurate targeting and allow for smaller image intensifier diameters to be used.
This illustration shows the dose rate of scattered radiation around a C-arm. The further away the surgeon/ORP is/are from the x-ray tube, image intensifier, and the patient, the lower the dose of scattered radiation. The 'inverse square law' states that the dose is reduced by the power of 2 of the distance to the x-ray source, ie, when the distance between source and surgeon/ORP is doubled, the dose of radiation is reduced by a quarter. Distance from the source is the best radiation protection. When the C-arm is in the lateral position, image intensification should occur for the shortest possible time, as scattered radiation is higher in this position than when the C-arm is in the AP position. The emission of scattered radiation when the C-arm is in the lateral position is at its maximum diagonally and laterally in the direction of the x-ray tube.
It is very important to use protective clothing when operating the C-arm, to protect the hands, eyes, thyroid, and body from exposure to radiation. The hands have the greatest exposure risk (during reduction and checking reduction). Radiation-protective gloves give a 60-64% decrease in exposure with 52 – 58 KV. The eyes are the most sensitive area of the body to radiation, and the first determinant of workload (radiation cataracts). Goggles with 0.15 mm lead-equivalent attenuate radiographic beams by 70%. A thyroid collar decreases the scattered radiation a further 2.5-fold. One study has shown that 85% of papillary carcinomas are radiation-induced. (Source: Devalla KL, Guha A, Devadoss VG (2004) The need to protect the thyroid gland during image intensifier use in orthopaedic procedures. Acta Orthop Belg ; 70 (5): 474-477.) An apron in the AP position decreases scattered radiation by 16-fold and in the lateral position by 4-fold.