Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
Add more filters










Database
Language
Publication year range
1.
Diagn Interv Imaging ; 100(7-8): 401-410, 2019.
Article in English | MEDLINE | ID: mdl-31130375

ABSTRACT

PURPOSE: To compare the noise-magnitude and noise-texture across two generations of iterative reconstruction (IR) algorithms proposed by three manufacturers according to the dose level. MATERIALS AND METHODS: Five computed tomography (CT) systems equipped with two generations of IR algorithms (hybrid/statistical IR [H/SIR] or full/partial model-based IR [MBIR]) were compared. Acquisitions on Catphan 600 phantom were performed at 120kV and three dose levels (3-, 7- and 12-mGy). Raw data were reconstructed using standard "soft tissue" kernel for filtered back projection and one iterative level of two generations of IR algorithms. Contrast to-noise-ratio (CNR) was computed using three regions of interest: two of them placed in the low-density polyethylene (LDPE) and Teflon® inserts and another placed on the solid water. Noise power spectrum (NPS) was computed to assess the noise-magnitude (NPS peak) and noise-texture (NPS spatial frequency). RESULTS: CNR increased significantly in MBIR compared to H/SIR algorithms for General-Electric (GE) Healthcare (45%±12 [SD]) and Philips Healthcare systems (62%±11 [SD]) (P<0.001). Regarding Siemens Healthineers systems, CNR of MBIR was significantly lower than that of H/SIR (mean difference: -4%±5 [SD]) (P<0.001) for Teflon® insert but not for LDPE insert (mean difference: -4%±7 [SD]) (P=N.S.). NPS peaks were lower with MBIR than with H/SIR for GE Healthcare (-42%±8 [SD]) and Philips Healthcare (-75%±4 [SD]) systems, whereas it was greater with MBIR than with H/SIR for Siemens Healthineers (13%±11 [SD]) systems. NPS spatial frequencies were higher with MBIR than with H/SIR for Siemens (14%±10 [SD]) but lower for others (-17%±5 [SD] for GE Healthineers and -55%±3 [SD] for Philips Healthcare systems). CONCLUSION: This study demonstrates that recent MBIR algorithms, by comparison with the preceding generation, differ according to the main manufacturers with respect to noise-magnitude and noise-texture.


Subject(s)
Algorithms , Image Processing, Computer-Assisted , Signal-To-Noise Ratio , Tomography, X-Ray Computed , Humans , Models, Statistical , Phantoms, Imaging
2.
Diagn Interv Imaging ; 99(5): 321-329, 2018 May.
Article in English | MEDLINE | ID: mdl-29396087

ABSTRACT

PURPOSE: To assess the value of the routine use of radiochromic films in abdominopelvic embolization procedures to improve patient follow-up. METHODS: A total of 55 patients who underwent transcatheter abdominopelvic embolization were prospectively included. Six types of procedures were evaluated including hepatic chemoembolization (HCE), gonadal veins embolization (GVE), uterine elective embolization (UEE), uterine urgent embolization (UUE), abdominal elective embolization (AEE), and abdominal urgent embolization (AUE). Dosimetric indicators (DIs) such as air-kerma (AK) and kerma-area-product (KAP) were collected and peak skin dose (PSD) was measured with radiochromic films. Correlations between PSD and DIs were searched for. RESULTS: The mean (±standard deviation [SD]) PSD for the various procedures were: 1033±502 mGy for HCE; 476±271 mGy for GVE; 460±171 mGy for UEE; 531±263 mGy for UUE; 708±896 mGy for AEE; 683±392 mGy for AUE. Strong correlations were observed between PSD and DIs (r=0.974 for AK and r=0.925 for KAP). PSD was>2Gy in one procedure and all procedures (7/132) procedures resulted in AK>2Gy, mostly for HCE and AEE. CONCLUSION: Dosimetry using radiochromic film is only appropriate for HCE, AEE and AUE, whereas dose-mapping systems present a more suitable solution for all embolizations including those with AK that occasionally exceed 2Gy.


Subject(s)
Embolization, Therapeutic/methods , Radiation Dosage , Radiography, Interventional/methods , Abdomen , Female , Humans , Male , Middle Aged , Pelvis , Prospective Studies , Radiometry/methods , Skin/radiation effects
3.
Phys Med ; 38: 16-22, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28610693

ABSTRACT

OBJECTIVE: To compare the use of a dose mapping software to Gafchromic film measurement for a simplified peak skin dose (PSD) estimation in interventional cardiology procedure. METHODS: The study was conducted on a total of 40 cardiac procedures (20 complex coronary angioplasty of chronic total occlusion (CTO) and 20 coronary angiography and coronary angioplasty (CA-PTCA)) conducted between January 2014 to December 2015. PSD measurement (PSDFilm) was obtained by placing XR-RV3 Gafchromic under the patient's back for each procedure. PSD (PSDem.dose) was computed with the software em.dose©. The calculation was performed on the dose metrics collected from the private dose report of each procedure. Two calculation methods (method A: fluoroscopic kerma equally spread on cine acquisition and B: fluoroscopic kerma is added to one air Kerma cine acquisition that contributes to the PSD) were used to calculate the fluoroscopic dose contribution as fluoroscopic data were not recorded in our interventional room. Statistical analyses were carried out to compare PSDFilm and PSDem.dose. RESULTS: The PSDFilm median (1st quartile; 3rd quartile) was 0.251(0.190;0.336)Gy for CA-PTCA and 1.453(0.767;2.011)Gy for CTO. For method-A, the PSDem.dose was 0.248(0.182;0.369)Gy for CA-PTCA and 1.601(0.892;2.178)Gy for CTO, and 0.267(0.223;0.446)Gy and 1.75 (0.912;2.584)Gy for method-B, respectively. For the two methods, the correlation between PSDFilm and PSDem.dose was strong. For all cardiology procedures investigated, the mean deviation between PSDFilm and PSDem.dose was 3.4±21.1% for method-A and 17.3%±23.9% for method-B. CONCLUSION: The dose mapping software is convenient to calculate peak skin dose in interventional cardiology.


Subject(s)
Radiation Dosage , Skin/radiation effects , Software , Adult , Aged , Aged, 80 and over , Angioplasty , Cardiology/methods , Coronary Angiography , Female , Fluoroscopy , Humans , Male , Middle Aged , Radiation Dosimeters , Radiometry
4.
Radiat Prot Dosimetry ; 174(3): 395-405, 2017 Apr 28.
Article in English | MEDLINE | ID: mdl-27522056

ABSTRACT

To assess the interest of Gafchromic films in detection of patient's peak skin dose (PSD) in interventional cardiology. A prospective study of 112 patients was conducted (July-December 2015). Three diagnostic and therapeutic procedures were evaluated: coronary angiography (CA), coronary angiography and coronary angioplasty for one or two vessels disease (CA-PTCA) and coronary angioplasty of complex chronic total occlusion (CTO). Dosimetric indicators (DIs) were collected and PSD were measured with Gafchromic films. Dose distribution was evaluated within 10 'Thorax Body-zone' defined by the system. Correlations between PSD and DI or dose distribution were computed. Delivered dose increased in complex procedures. The PSD were 0.121 ± 0.063 Gy for CA, 0.256 ± 0.142 Gy for CA-PTCA and 1.116 ± 0.721 Gy for CTO. High correlations were observed for PSD and DI as well for dose distribution within the 'Thorax Body-zone'. Film dosimetry is suggested for CTO procedures since the threshold of 2 Gy for skin injuries is likely to be exceeded.


Subject(s)
Coronary Angiography , Radiation Dosage , Cardiology , Film Dosimetry , Humans , Prospective Studies , Radiography, Interventional , Skin
SELECTION OF CITATIONS
SEARCH DETAIL
...