Mean Glandular Dose and CDMAM Phantom Image Quality for Siemens Mammomat Inspiration

In performing breast screening, a mammography must be capable of imaging microcalcifications with the smallest possible size. However, the mean glandular dose (MGD) should not exceed the recommended limits. To achieve the goal then the utilization of target/filter combination should be adjusted to the thickness of the breast. The evaluation of image quality against variations in target/filter combinations can be done by using CDMAM phantom. There are two methods of CDMAM phantom image quality assessment, and the digital method is considered superior to the manual one. In addition to the evaluation of image quality, MGD received by the phantom was also calculated by multiplying the air kerma value at each thickness with the air kerma conversion factor into MGD. The calculation of MGD follow the equation and convertion factor that published by IAEA Human Health Series No. 17 – Quality Assurance Programme for Digital Mammography, then being compared with three another publication. The best image quality for the phantom thickness below 32 mm achieved by using Mo/Mo target/filter combination, meanwhile for the fantom thickness above 45 mm achieved by using Mo/Rh

Metode line profile: pendekatan terhadap evaluasi kuantitatif citra Computed Radiography thoraks pada pasien pediatrik

Tujuan dari penelitian ini adalah untuk menunjukkan fisibilitas metode line profile sebagai metode evaluasi kuantitatif citra computed radography thoraks pasien pediatrik. Sampel berupa 36 citra thoraks pediatrik yang terdiri dari 26 citra thoraks normal dan 10 citra thoraks abnormal, diperoleh dengan menggunakan sistem CR. Line profile dibuat dengan menggunakan perangkat lunak imageJ dan dikuantisasi menggunakan fortran 90. Setiap line profile diberi enam perlakuan (metode) yang berbeda, yakni tanpa modifikasi nilai piksel (metode I), modifikasi nilai piksel menjadi kontras region of interest (ROI) tulang (metode II), modifikasi nilai piksel menjadi kontras ROI thoraks (metode III), normalisasi rentang nilai piksel (metode IV), normalisasi rentang nilai piksel dan modifikasi kontras ROI tulang (metode V), serta normalisasi rentang nilai piksel dan modifikasi kontras ROI thoraks (metode VI). Verifikasi metode dilakukan dengan menggunakan coefficient of variation (CoV). Metode terbaik dipilih dan digunakan sebagai acuan line profile normal yang akan dibandingkan dengan line profile citra abnormal. Untuk membandingkan secara kuantitatif line profile normal dan abnormal, diskrepansi (δ) digunakan sebagai parameter. Hasil penelitian menunjukkan bahwa metode line profile dengan menggunakan normalisasi rentang nilai piksel adalah metode yang memiliki fisibilitas untuk membedakan citra normal dan abnormal. Dari metode ini, kelainan dengan δ terkecil adalah bronchitis dan δ terbesar adalah effusion. Penelitian lanjutan diperlukan untuk meningkatkan fisibilitas metode ini untuk kasus abnormalitas lain

Occupational Dose Estimation with Field Size, Position and C-Arm Gantry Tilt Variations During Interventional Cardiology Procedures

In Interventional Cardiology, dose received by the patient is relatively higher, while the occupational would receive scattered radiation dose whose quality is relatively lower. However, the occupational received accumulative doses of all cardiovascular procedures were done over the years. Therefore, the purpose of this paper will focus to estimate the distribution of scattered dose to occupational without any protective shielding in the Cath Lab. The scattered dose rate was measured by using survey detector of Unfors Xi. The detector was placed at 6 different positions around the phantom. Each measurement position has eleven points from 25 to 175 cm above the floor with increment of 15 cm as the illustration of partial height of occupational organ. Experimentally a Rando phantom was irradiated by automatic pulsed fluoroscopy with condition varies in the range of 88-93 kV and 5.7-9.4 mA depend on gantry tilt and field size. The Philips C-arm gantry tilt was varied at 0o PA projection, 20o and 30o Caudal, 20o and 30o Cranial, and 40o and 50o Left Anterior Oblique, and also Flat Panel Detector (FPD) was varied at 20 x 20 and 25 x 25 cm2. Generally, the greatest dose rate was known at level corresponding to the waist (100 cm) of occupational and the lowest at head areas (175 cm) of occupational which is 2.49 mGv/h and 0.02 mGy/h, respectively. The given data showed that the scattered fractions are in the range of 0.001-0.060% from its primary dose at isocenter. The scattered doses tend to increase with gantry tilt for all positions. Increasing field size of FPD will decreased the scattered fraction from its dose at isocenter, and also it affects the scattered dose rate

Entrance Skin Dose Measurement Using GafChromic Dosimetry Film for Adult Patients Undergoing Coronary Angiography (CA) and Percutaneous Transluminal Coronary Angioplasty (PTCA)

The complexity of interventional procedures has led to increasingly longer procedure time that require significant fluoroscopic use. Fluoroscopy time is proportional to the patient dose. Once a threshold dose has been exceeded, the severity of the radiation effect at any point on the skin increases with increasing dose. The threshold dose for transient skin injuries is typically 2 Gy for erythema, the earliest detectable effect of radiation on the skin. Therefore, it is important to monitor radiation entrance exposure to the patients. Since it is not uncommon that a patient not only perform a single examination, the skin dose per examination is recommended to note if in the future radiation effect on the patient's skin arises. The skin dose records will help further treatment. The aim of this study is to evaluate patient dose in interventional radiology. Twenty one cardiac intervention procedures were studied: 12 coronary angiography (CA) dan 9 percutaneous transluminal coronary angioplasty (PTCA). The entrance surface dose were measure using DAP (dose-area product) and GafChromic XR-RV3 radiochromic film attached to the skin. GafChromic film measurement obtained the skin dose distribution on the back of the coronary area. In addition, we also measure the patient backscattering dose on the thyroid, gonad and eyes. Image analysis was performed using red channel component of standard RGB (red, green and blue) color space image. The correlation between maximum radiation surface dose and dose area product for two interventional procedures was investigated. We found a good correlation of DAP (dose-area product) and maximum entrance skin dose (R2 = 0.79, R2 = 0.52 for CA and R2 = 0.74 for PTCA). However, fluoroscopy time seems to have a poor relationship with the patient entrance surface dose (R2 = 0.43). The total irradiation time, DAP and entrance surface dose for PTCA procedures is higher than CA procedures because of the PTCA procedure is more complex. The entrance surface dose delivered to the patient can be easily measured when GafChromic films are used. The GafChromic dosimetry allows precise mapping of the skin dose distribution, when placed close to the skin. The GafChromic film results that the radiation dose to the surface for PTCA procedure greater than CA

Virtual study to investigate the detectability of breast abnormalities on 2D mammography and digital breast tomosynthesis

This paper describes the use of virtual clinical trial software, as developed and improved in the frame of the Horizon2020 MaXIMA project, to study particular aspects of 2D mammography and digital breast tomosynthesis. A voxel-based breast phantom with inserted mathematical models of an irregular mass and two microcalcifications was created. Image acquisition was simulated by using XRAYImagingSimulator, while image reconstruction was accomplished with FDKR software. Series of images were created for different angular ranges with an identical total dose. Detectability of the abnormalities was investigated using visual assessment and quantitative measurements. The results agree with other studies in literature studying the same aspects and therefore confirm the value of the new framework for other future applications

Towards a Phantom for Multimodality Performance Evaluation of Breast Imaging: A 3D Structured Phantom with Simulated Lesions Tested for 2D Digital Mammography

© Springer International Publishing Switzerland 2016. The aim of this work is to test whether a 3D structured phantom with simulated lesions can be used for performance evaluation of 2D digital mammography, as a step towards a multimodality phantom. A phantom, developed for breast tomosynthesis was therefore applied on 23 digital mammography systems. Ten images were acquired at the clinically used dose and for 11 systems also at half and double dose. The images were read in a four-alternative forced choice (4-AFC) paradigm by 5 readers. CDMAM phantom acquisitions were also performed. It was possible to calculate diameter thresholds of the simulated masses and microcalcifications that guarantee 62.5% correct response. The results showed the expected sensitivity with mean glandular dose: detectability of microcalcifications improved with dose, whereas the detectability of masses was not affected. Systems of the same manufacturer and operated at similar doses had very similar detectability scores. Percentage correctly detected microcalcifications with average diameter 119 μm correlated with CDMAM based gold thickness thresholds. Present phantom, developed and tested for tomosynthesis, is also a good candidate for 2D mammography, suggesting its use for (future) benchmarking of at least two types of imaging systems.status: publishe