01-4 How does the X-ray tube potential affect patient dose and image quality in abdominal CT?

Background: Concern has been raised regarding the mounting collective radiation doses from computed tomography (CT), increasing the risk of radiation-induced cancers in exposed populations. Purpose: To compare radiation dose and image quality in a chest phantom and in patients for the diagnosis of pulmonary embolism (PE) at 100 and 120 peak kilovoltage (kVp) using 16-multichannel detector computed tomography (MDCT). Material and Methods: A 20-ml syringe containing 12 mg I/ml was scanned in a chest phantom at 100/120 kVp and 25 milliampere seconds (mAs). Consecutive patients underwent 100 kVp ( n = 50) and 120 kVp ( n = 50) 16-MDCT using a “quality reference” effective mAs of 100, 300 mg I/kg, and a 12-s injection duration. Attenuation (CT number), image noise (1 standard deviation), and contrast-to-noise ratio (CNR; fresh clot = 70 HU) of the contrast medium syringe and pulmonary arteries were evaluated on 3-mm-thick slices. Subjective image quality was assessed. Computed tomography dose index (CTDIvol) and dose–length product (DLP) were presented by the CT software, and effective dose was estimated. Results: Mean values in the chest phantom and patients changed as follows when X-ray tube potential decreased from 120 to 100 kVp: attenuation +23% and +40%, noise +38% and +48%, CNR −6% and 0%, and CTDIvol −38% and −40%, respectively. Mean DLP and effective dose in the patients decreased by 42% and 45%, respectively. Subjective image quality was excellent or adequate in 49/48 patients at 100/120 kVp. No patient with a negative CT had any thromboembolism diagnosed during 3-month follow-up. Conclusion: By reducing X-ray tube potential from 120 to 100 kVp, while keeping all other scanning parameters unchanged, the radiation dose to the patient may be almost halved without deterioration of diagnostic quality, which may be of particular benefit in young individuals.

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Establishing a quality assurance baseline for radiological protection of patients undergoing diagnostic radiology

South African Journal of Radiology ◽

10.4102/sajr.v15i3.370 ◽

2011 ◽

Vol 15 (3) ◽

pp. 70 ◽

Cited By ~ 1

Author(s):

Geoffrey K Korir ◽

Jeska Sidika Wambani ◽

Ian K Korir

Keyword(s):

Quality Control ◽

Quality Assurance ◽

Image Quality ◽

Radiation Exposure ◽

High Speed ◽

Quality Criteria ◽

Patient Dose ◽

Radiological Protection ◽

X Ray ◽

High Speed Film

Background. The wide use of ionising radiation in medical care has resulted in the largest man-made cause of radiation exposure. In recent years, diagnostic departments in Kenya have adapted the high-speed film/screen combination without well-established quality control, objective image quality criteria, and assessment of patient dose. The safety of patients in terms of justification and the as-low-as-reasonably-achievable (ALARA) principle is inadequate without quality assurance measures. Aim. This study assessed the level of film rejects, device performance, image quality and patient dose in 4 representative hospitals using high-speed film/screen combination. Results. The X-ray equipment quality control tests performance range was 67% to 90%, and 63% of the radiographs were of good diagnostic value. The measured prevalent chest examination entrance surface dose (ESD) showed levels above the international diagnostic reference levels (DRLs), while lumbar spine and pelvis examination was the largest source of radiation exposure to patients. Conclusion. The optimisation of patient protection can be achieved with optimally performing X-ray equipment, the application of good radiographic technique, and continuous assessment of radiographic image quality.

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MO-FF-A4-02: Effects of Added X-Ray Beam Cu Filtration On Image Quality and Patient Dose in Digital Radiography

Medical Physics ◽

10.1118/1.3182296 ◽

2009 ◽

Vol 36 (6Part21) ◽

pp. 2713-2713

Author(s):

E Christodoulou ◽

M Goodsitt ◽

B Bailey ◽

R Young

Keyword(s):

Image Quality ◽

Digital Radiography ◽

Patient Dose ◽

X Ray

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Commentary: progress in optimization of patient dose and image quality in x-ray diagnostics

Physics in Medicine and Biology ◽

10.1088/0031-9155/44/2/001 ◽

1999 ◽

Vol 44 (2) ◽

Cited By ~ 5

Author(s):

G A Carlsson ◽

H-P Chan

Keyword(s):

Image Quality ◽

Patient Dose ◽

X Ray

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Image quality in abdominal CT using an iodine contrast reduction algorithm employing patient size and weight and low kV CT technique

Acta Radiologica ◽

10.1177/0284185119898655 ◽

2020 ◽

Vol 61 (9) ◽

pp. 1186-1195

Author(s):

Veena R Iyer ◽

Eric C Ehman ◽

Ashish Khandelwal ◽

Michael L Wells ◽

Yong S Lee ◽

...

Keyword(s):

Image Quality ◽

Portal Vein ◽

Reduction Algorithm ◽

Diagnostic Confidence ◽

Abdominal Ct ◽

Contrast Dose ◽

Contrast Enhanced ◽

Tube Potential ◽

Patients At Risk ◽

Contrast Reduction

Background Low tube potential-high tube current computed tomography (CT) imaging allows reduction in iodine-based contrast dose and may extend the benefit of routine contrast-enhanced CT exams to patients at risk of nephrotoxicity. Purpose To determine the ability of an iodine contrast reduction algorithm to maintain diagnostic image quality for contrast-enhanced abdominal CT. Material and Methods CT exams with iodine contrast reduction were prescribed for patients at risk for renal dysfunction. The iodine contrast reduction algorithm combines weight-based contrast volume reduction with patient width-based low tube potential selection and bolus-tracking. Control exams with routine iodine dose were selected based on weight, width, and scan protocol. Three radiologists evaluated image quality and diagnostic confidence using a 4-point scale (<2 acceptable). Another radiologist assessed contrast reduction indications and measured portal vein and liver contrast-to-noise ratios. Results Forty-six contrast reduction algorithm and control exams were compared (mean creatinine 1.6 vs. 1.2 mg/dL, P ≤ 0.0001). Thirty-nine contrast reduction patients had an eGFR <60 mL/min/1.73m2 and 15 had single or transplanted kidney. Mean iodine contrast dose was lower in the contrast reduction group (20.9 vs. 39.4 g/mL, P < 0.0001). Diagnostic confidence was rated as acceptable in 95% (131/138) of contrast reduction and 100% of control exams (1.18–1.28 vs. 1.02–1.13, respectively; P > 0.06). Liver attenuation and contrast-to-noise ratio (CNR) were similar ( P = 0.08), but portal vein attenuation and CNR were lower with contrast-reduction (mean 176 vs. 198 HU, P = 0.02; 13 vs. 16, P = 0.0002). Conclusion This size-based contrast reduction algorithm using low kV and bolus tracking reduced iodine contrast dose by 50%, while achieving acceptable image quality in 95% of exams.

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