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Pediatric CT Dose Reductions. Laura T. Smith, MS, DABR Senior Health Physicist St. John Providence Health. Why is CTDI in mGy, and patient dose DLP in mSv?. Typical Diagnostic Exposures. www.hps.org data. AAPM Outside of Expected Values. How do you Reduce Radiation Risks in CT?.
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Pediatric CT Dose Reductions Laura T. Smith, MS, DABRSenior Health PhysicistSt. John Providence Health
Typical Diagnostic Exposures www.hps.org data
How do you Reduce Radiation Risks in CT? Perform only necessary scans. Education and training for staff. Purchase dose reduction software. Image Gently and Image Wisely. Use reduced imaging techniques with consult from your physicist/radiologist. Become an accredited facility – ACR or IAC CT approvals require multiple layers of training, policies, quality control, physics support, dosimetry guidance. Follow new rules
Performing only Necessary Scans Explaining to patient who insists upon having a CT scan, the appropriate risk versus benefits. Using the ACR’s website on appropriateness criteria. http://www.acr.org/SecondaryMainMenuCategories/quality_safety/app_criteria.aspx
Dose Reduction Software GE (A SiR) adaptive statistical iterative reconstruction, allowing for dose reduction of up to 50%. SafeCT, Sharpview, Caredose, DoseRight (Zdom), Clarity, … A box you can check to allow mAs modulation, which reduces patient dose in different areas, based upon attenuation and the scout information.
Tube Current Modulation (TCM) Image Courtesy of Dianna Cody, Ph.D – MD Anderson
Image Gently / Image Wisely Radiation Safety in Adult Medical Imaging
Image Gently There's no question: CT helps us save kids' lives. But, when we image, radiation matters! • Children are more sensitive to radiation. • What we do now lasts their lifetimes. • So, when we image, let's image gently: More is often not better. • When CT is the right thing to do: • Child size the kVp and mA • One scan (single phase) is often enough • Scan only the indicated area
Image Gently 129 mAs 153 mAs 177 mAs 198 mAs 228 mAs 270 mAs 300 mAs 381 mAs
ACR Working with ACR Five things Physicians and Patients should question on CT: Don’t do imaging for uncomplicated headache. Don’t image for suspected pulmonary embolism (PE) without moderate or high pre-test probability. Avoid admission or preoperative chest x-rays for ambulatory patients with unremarkable history and physical exam. Don’t do CT for the evaluation of suspected appendicitis in children until after ultrasound has been considered as an option. Don’t recommend follow-up imaging for clinically inconsequential adnexal cysts.
State of Michigan New CT rules December 8, 2011 Your state might have similar rules.
TJC Rules July 2015 Provide physicians and technologists with reference doses based on anatomy, purpose of the study, and patient size. Establish appropriate dose ranges for high-volume and high-dose diagnostic imaging studies. Investigate patterns outside the range of appropriate doses. Track radiation doses from exams repeated due to insufficient image quality or lack of availability of previous studies to identify the causes. Address and resolve these problems through education and other measures. Record the dosage or exposure as part of the study’s summary report of findings. Ensure all physicians and technologists who prescribe diagnostic radiation or use diagnostic radiation equipment receive dosing education and are trained on the specific model of equipment being used. Create and implement processes that enable radiologists to provide guidance to and dialogue with referring physicians regarding the appropriate use of diagnostic imaging using the American College of Radiology’s Appropriateness Criteria.
Shielding patients in CT • There are positives and negatives in shielding in CT. • Low dose reduction, High possibility of increased dose. • If you decide to shield you MUST implement a training program and policy. • No shields during scout views. Write it on the shield – do not use during scout. • Shields must NOT be in field of view during imaging, unless specific Breast Bismuth shields. • Breast Bismuth shields should rise up off the patient. • Shields should wrap around the patient with the opening on the top side.