"[
ABSTRAKDosimetri CT scan dapat dilakukan dengan menggunakan konsep CTDI, Monte
Carlo, atau dengan pengukuran langsung dalam fantom fisis. Pengukuran
langsung menggunakan thermoluminescent dosimeter (TLD) merupakan prosedur
yang rumit dan membutuhkan waktu yang lama. Saat ini sudah tersedia film
radiochromic yang dapat digunakan di radiologi. Pada penelitian ini dilakukan
pengukuran distribusi dosis radiasi dalam fantom Rando menggunakan film
Gafchromic XR-QA2 dan TLD. Film Gafchromic XR-QA2 dan TLD dikalibrasi
di CT scanner Siemens Sensation 64. Pengukuran distribusi dosis dengan film
dilakukan pada faktor pitch 0.8, 1.0, dan 1.4. Film Gafchromic XR-QA2
disisipkan diantara slab 22-23 (Film A), 23-24 (Film B), dan slab 24-25 (Film C).
Pengukuran distribusi dosis dengan TLD dilakukan dalam slab nomor 23 dengan
faktor pitch 1.4. Film Gafchromic XR-QA2 yang telah dieksposi dipindai dengan
flatbed scanner Epson Perfection V700 Photo. Dosis serap tulang belakang pada
Film A, Film B, dan Film C yang dieksposi dengan faktor pitch 1.4 secara
berturut-turut adalah 2.0 mGy, 1.9 mGy, dan 2.2 mGy. Berdasarkan profil dosis,
rata-rata dosis serap pada film yang dieksposi dengan faktor pitch 1.0 dan 1.4
secara berturut-turut adalah 8% dan 24% lebih tinggi dibanding rata-rata dosis
serap pada film yang dieksposi dengan faktor pitch 0.8. Rentang dosis hasil
pengukuran dengan TLD adalah (1.9 ± 0.1) – (2.3 ± 0.2) mGy dan rentang dosis
hasil pengukuran dengan film Gafchromic XR-QA2 adalah 1.8 – 2.3 mGy dengan
perbedaan maksimum 10.6%. Perbedaan tersebut masih berada dalam rentang
keakurasian TLD yaitu < 15%. Berdasarkan hasil tersebut, film Gafchromic XRQA2
dapat digunakan untuk pengukuran dosis CT scan selanjutnya.
ABSTRACTComputed tomography (CT) dosimetry can be approached by using CTDI
method, Monte Carlo computer technique, and direct measurement within
physical phantom. Direct measurement using thermoluminescent dosimeters
(TLDs) is a laborious procedure. Radiochromic film for radiology application was
available. In this study, dose distribution within adult anthropomorphic physical
phantom was measured using TLD and Gafchromic XR-QA2 film. TLD and
Gafchromic XR-QA2 film was calibrated on CT scanner Siemens Sensation 64.
Gafchromic XR-QA2 film was sandwiched between slab Rando phantom number
22-23 (Film A), 23-24 (Film B), and 24-25 (Film C). Pitch factor 0.8, 1.0, and 1.4
were used. TLDs were placed at the holes in the slab number 23 of
anthropomorphic phantom. TLDs were scanned using pitch factor 1.4. After
exposure, Gafchromic XR-QA2 film was digitized using Epson Perfection V700
Photo flatbed scanner. Absorbed dose at vertebra on Film A, Film B, and Film C
which exposed by using pitch 1.4 respectively were 2.0 mGy, 1.9 mGy, and 2.2
mGy. Based on dose profile, average dose of XR-QA2 film which exposed by
using pitch 1.0 and 1.4 respectively were 8% and 24% higher than average dose of
XR-QA2 film which exposed by pitch 0.8. TLDs dose range were (1.9 ± 0.1) –
(2.3 ± 0.2) mGy and Gafchromic XR-QA2 film dose range were 1.8 – 2.3 mGy
with maximum difference 10.6%. The difference is still within the range of TLD
accuracy, < 15%. Based on this result, Gafchromic XR-QA2 film can be used to
measure CT dose, Computed tomography (CT) dosimetry can be approached by using CTDI
method, Monte Carlo computer technique, and direct measurement within
physical phantom. Direct measurement using thermoluminescent dosimeters
(TLDs) is a laborious procedure. Radiochromic film for radiology application was
available. In this study, dose distribution within adult anthropomorphic physical
phantom was measured using TLD and Gafchromic XR-QA2 film. TLD and
Gafchromic XR-QA2 film was calibrated on CT scanner Siemens Sensation 64.
Gafchromic XR-QA2 film was sandwiched between slab Rando phantom number
22-23 (Film A), 23-24 (Film B), and 24-25 (Film C). Pitch factor 0.8, 1.0, and 1.4
were used. TLDs were placed at the holes in the slab number 23 of
anthropomorphic phantom. TLDs were scanned using pitch factor 1.4. After
exposure, Gafchromic XR-QA2 film was digitized using Epson Perfection V700
Photo flatbed scanner. Absorbed dose at vertebra on Film A, Film B, and Film C
which exposed by using pitch 1.4 respectively were 2.0 mGy, 1.9 mGy, and 2.2
mGy. Based on dose profile, average dose of XR-QA2 film which exposed by
using pitch 1.0 and 1.4 respectively were 8% and 24% higher than average dose of
XR-QA2 film which exposed by pitch 0.8. TLDs dose range were (1.9 ± 0.1) –
(2.3 ± 0.2) mGy and Gafchromic XR-QA2 film dose range were 1.8 – 2.3 mGy
with maximum difference 10.6%. The difference is still within the range of TLD
accuracy, < 15%. Based on this result, Gafchromic XR-QA2 film can be used to
measure CT dose]"
