scholarly journals Converting Dose-Length Product to Effective Dose at CT

Radiology ◽  
2008 ◽  
Vol 248 (3) ◽  
pp. 995-1003 ◽  
Author(s):  
Walter Huda ◽  
Kent M. Ogden ◽  
Mohammad R. Khorasani
Dose-Response ◽  
2020 ◽  
Vol 18 (4) ◽  
pp. 155932582097313
Author(s):  
Dario Baldi ◽  
Liberatore Tramontano ◽  
Vincenzo Alfano ◽  
Bruna Punzo ◽  
Carlo Cavaliere ◽  
...  

For decades, the main imaging tool for multiple myeloma (MM) patient’s management has been the conventional skeleton survey. In 2014 international myeloma working group defined the advantages of the whole-body low dose computed tomography (WBLDCT) as a gold standard, among imaging modalities, for bone disease assessment and subsequently implemented this technique in the MM diagnostic workflow. The aim of this study is to investigate, in a group of 30 patients with a new diagnosis of MM, the radiation dose (CT dose index, dose-length product, effective dose), the subjective image quality score and osseous/extra-osseous findings rate with a modified WBLDCT protocol. Spectral shaping and third-generation dual-source multidetector CT scanner was used for the assessment of osteolytic lesions due to MM, and the dose exposure was compared with the literature findings reported until 2020. Mean radiation dose parameters were reported as follows: CT dose index 0.3 ± 0.1 mGy, Dose-Length Product 52.0 ± 22.5 mGy*cm, effective dose 0.44 ± 0.19 mSv. Subjective image quality was good/excellent in all subjects. 11/30 patients showed osteolytic lesions, with a percentage of extra-osseous findings detected in 9/30 patients. Our data confirmed the advantages of WBLDCT in the diagnosis of patients with MM, reporting an effective dose for our protocol as the lowest among previous literature findings.


Radiology ◽  
2009 ◽  
Vol 250 (2) ◽  
pp. 604-605 ◽  
Author(s):  
Paul C. Shrimpton ◽  
Barry F. Wall

2021 ◽  
Vol 11 (8) ◽  
pp. 2130-2136
Author(s):  
Ziyad Awadh Alrowaili ◽  
M. Ashari

A safe radiation dose from computed tomography (CT) is normally specified through the Computed Tomography Dose Index (CTDI) as an “effective dose.” Radiation exposure from CT is relatively high in comparison with other radiological tests. In this paper, we evaluate doses used on adult patients during typical CT scans, in Al Jouf, the northern region of Saudi Arabia. Scanning processes were taken place in different parts of the body; including the pelvis, head, abdomen, and chest. The dose indices were calculated using the CT-expo v2.5 computer software. A comparison of the results with similar investigations, regionally and globally, was made. Other comparisons between displayed and calculated dose indices were also performed. The main values of CT volume are the dose index (CTDIvol) and dose-length product (DLP). The effectiveness results for head CTs were 45.0 mGy, 488 mGy.cm, and 5.2 mSv; while for pelvic CTs they were 16.4 mGy, 391 mGy.cm, and 4.0 mSv; whereas for abdominal CTs they were 22.2 mGy, 613 mGy.cm, and 6.5 mSv; finally they were 17.5 mGy, 380 mGy.cm, and 3.9 mSv for chest CTs. It is confirmed that the values obtained are within the internationally accepted values, except for the values of the head examination, in which the effective dose value of 5.2 mSv was higher than the recommended value. This work gives an overview of the doses received by adult patients during regular CT examination. It is the first regional CT dose survey and provides a baseline for improvement and quality control in the region of Al Jouf.


Author(s):  
Yusuke Inoue ◽  
Yuka Yonekura ◽  
Kazunori Nagahara ◽  
Ayuka Uehara ◽  
Hideki Ikuma

Abstract For radiation dose assessement of computed tomography (CT), effective dose (ED) is often estimated by multiplying the dose-length product (DLP), provided automatically by the CT scanner, by a conversion factor. We investigated such conversion in CT venography of the lower extremities performed in conjunction with CT pulmonary angiography. The study subjects consisted of eight groups imaged using different scanners and different imaging conditions (five and three groups for the GE and Siemens scanners, respectively). Each group included 10 men and 10 women. The scan range was divided into four anatomical regions (trunk, proximal thigh, knee and distal leg), and DLP was calculated for each region (regional DLP). Regional DLP was multiplied by a conversion factor for the respective region, to convert it to ED. The sum of the ED values for the four regions was obtained as standard ED. Additionally, the sum of the four regional DLP values, an approximate of the scanner-derived DLP, was multiplied by the conversion factor for the trunk (0.015 mSv/mGy/cm), as a simplified method to obtain ED. When using the simplified method, ED was overestimated by 32.3%−70.2% and 56.5%−66.2% for the GE and Siemens scanners, respectively. The degree of overestimation was positively and closely correlated with the contribution of the middle and distal portions of the lower extremities to total radiation exposure. ED/DLP averaged within each group, corresponding to the conversion factor, was 0.0089−0.0114 and 0.0091−0.0096 mSv/mGy/cm for the GE and Siemens scanners, respectively. In CT venography of the lower extremities, ED is greatly overestimated by multiplying the scanner-derived DLP by the conversion factor for the trunk. The degree of overestimation varies widely depending on the imaging conditions. It is recommended to divide the scan range and calculate ED as a sum of regional ED values.


2020 ◽  
Vol 189 (1) ◽  
pp. 35-47
Author(s):  
Anna Bågenholm ◽  
Pål Løvhaugen ◽  
Rune Sundset ◽  
Tor Ingebrigtsen

Abstract This audit describes ionizing and non-ionizing diagnostic imaging at a regional trauma centre. All 144 patients (males 79.2%, median age 31 years) met with trauma team activation from 1 January 2015 to 31 December 2015 were included. We used data from electronic health records to identify all diagnostic imaging and report radiation exposure as dose area product (DAP) for conventional radiography (X-ray) and dose length product (DLP) and effective dose for CT. During hospitalization, 134 (93.1%) underwent X-ray, 122 (84.7%) CT, 92 (63.9%) focused assessment with sonography for trauma (FAST), 14 (9.7%) ultrasound (FAST excluded) and 32 (22.2%) magnetic resonance imaging. One hundred and sixteen (80.5%) underwent CT examinations during trauma admissions, and 73 of 144 (50.7%) standardized whole body CT (SWBCT). DAP values were below national reference levels. Median DLP and effective dose were 2396 mGycm and 20.42 mSv for all CT examinations, and 2461 mGycm (national diagnostic reference level 2400) and 22.29 mSv for a SWBCT.


2019 ◽  
Vol 26 (2) ◽  
pp. 517-527
Author(s):  
Stewart Midgley ◽  
Nanette Schleich ◽  
Alex Merchant ◽  
Andrew Stevenson

The dose length product (DLP) method for medical computed tomography (CT) dosimetry is applied on the Australian Synchrotron Imaging and Medical Beamline (IMBL). Beam quality is assessed from copper transmission measurements using image receptors, finding near 100% (20 keV), 3.3% (25 keV) and 0.5% (30–40 keV) relative contributions from third-harmonic radiation. The flat-panel-array medical image receptor is found to have a non-linear dose response curve. The amount of radiation delivered during an axial CT scan is measured as the dose in air alone, and inside cylindrical PMMA phantoms with diameters 35–160 mm for mono-energetic radiation 25–100 keV. The radiation output rate for the IMBL is comparable with that used for medical CT. Results are presented as the ratios of CT dose indices (CTDI) inside phantoms to in air with no phantom. Ratios are compared for the IMBL against medical CT where bow-tie filters shape the beam profile to reduce the absorbed dose to surface organs. CTDI ratios scale measurements in air to estimate the volumetric CTDI representing the average dose per unit length, and the dose length product representing the absorbed dose to the scanned volume. Medical CT dose calculators use the DLP, beam quality, axial collimation and helical pitch to estimate organ doses and the effective dose. The effective dose per unit DLP for medical CT is presented as a function of body region, beam energy and sample sizes from neonate to adult.


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