- General departmental approach to radiation
- Availability of sub-specialized radiologists for consultation
- Tailored techniques
- Careful quality control
- Latest technology for radiation dose reduction
- Bismuth shields
- Gonadal Shielding and Beam Collimation Policy
- UCSF Medical Center Radiation Protection Committee
- UCSF Department of Radiology and Biomedical Imaging Radiation Oversight Committee
- UCSF in comparison to other hospitals
- Contact Us
General departmental approach to radiation
The Department of Radiology and Biomedical Imaging is fully committed to minimizing exposure to ionizing radiation for our patients and staff. The Department follows the principle of "ALARA" (As Low As Reasonably Achievable) in relation to ionizing radiation and patient safety, and always uses the lowest radiation dose consistent with getting imaging results that are of appropriate diagnostic quality. We realize that several recent medical publications [1, 2] have received a great deal of press coverage, and that many patients are now concerned about their radiation exposure. Being informed and aware of radiation risk is absolutely appropriate, but our patients should understand that:
- Much of the recent coverage has been primarily focused on the risk of radiation. It should be remembered that the careful use of radiation for imaging can improve diagnosis and treatment - there are substantial benefits to these tests that must be considered in any balanced discussion of risk versus benefit.
- The risk of low dose radiation used in imaging is unproven, and based on extrapolation from high dose radiation. Such extrapolation is a cautious and safe approach to risk estimation, but it is also possible that low dose radiation is not dangerous at all.
- The risk of low dose radiation, if it exists, is small. One widely publicized reported study estimated that CT scans done in the United States during 2007 may cause 15,000 cancer deaths [3]. This sounds scary, but is unproven and should be considered in the context of other risks. For example, it is estimated that smoking kills 440,000 Americans every year [4], a much greater and easily reversible proven death toll from a manmade product that produces no medical benefit.
- Fazel R, Krumholz HM, Wang Y, Ross JS, Chen J, Ting HH, Shah ND, Nasir K, Einstein AJ, Nallamothu BK. Exposure to low-dose ionizing radiation from medical imaging procedures. New England Journal of Medicine 2009; 361: 849-57.
- Smith-Bindman R, Lipson J, Marcus R, Kim KP, Mahesh M, Gould R, Berrington de González A, Miglioretti DL. Radiation dose associated with common computed tomography examinations and the associated lifetime attributable risk of cancer. Archives of Internal Medicine 2009; 169: 2078-86.
- Berrington de González A, Mahesh M, Kim K-P; et al. Projected cancer risks from computed tomographic scans performed in the United States in 2007. Archives of Internal Medicine 2009; 169: 2071-2077.
- http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5235a4.htm
Availability of sub-specialized radiologists for consultation
We recognize that minimizing radiation dose begins with the proper selection of an imaging study for the specific needs of every individual patient. Our faculty, fellows and residents are available 24 hours a day, 7 days a week to consult with referring clinicians regarding the relative benefits of tests that may or may not involve radiation exposure, and we encourage referring physicians to consider tests that do not involve radiation (e.g., ultrasound or MRI) if they can provide the same information as a CT scan or other test with ionizing radiation. Specific examples include using MRI instead of CT to evaluate inflammatory bowel disease and to diagnose appendicitis in pregnancy.
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Tailored techniques
Specific radiation dose protocols are in use and routinely reviewed for each body part, and special low radiation dose protocols have been developed for certain indications in pediatric patients and during CT guided procedures. For the latter, our China Basin Imaging Center is proud to be one of few facilities in Northern California to use special low dose CT "step and shoot" mechanisms during CT guided spine procedures, which lowers the radiation dose to the patient while providing more precise information regarding the placement of medication.
Careful quality control
All radiology devices are calibrated to ensure that their output is within the specified safe range and all equipment is tested at least annually. In addition, quarterly maintenance is done on all CT scanners in the department to ensure that they are operating to specification. We are in compliance with all national standards for Radiation Safety. After the concerns raised by radiation overdoses at Cedars-Sinai Hospital in 2009, the UCSF Office of Environmental Health & Safety reviewed the dose delivered by all our CT scanners and found we are in compliance with national standards.
Latest technology for radiation dose reduction
All UCSF CT Scanners are equipped with the latest generation automatic dose modulation software that further reduces the radiation dose to various body parts during a scan. For example less radiation is needed to image parts of the thorax as compared with the abdomen, and less is needed for a smaller person or body part, than a larger one. This software allows our CT machines to vary the radiation dose to minimize the total radiation exposure and results in an up to 50% lower dose compared with older generation CT scanners [1]. UCSF will soon install two new CT scanners that have the capacity to reduce dose by another 30-50%, using newer post processing algorithms that will allow lower dose regimens with the same diagnostic information, and we will propagate this technology (special hardware and software required) across our installed base of CT scanners.
- Smith AB, Dillon WP, Gould R, Wintermark M. Radiation dose-reduction strategies for neuroradiology CT protocols. American Journal of Neuroradiology 2007; 28: 1628-32.
Bismuth shields
Bismuth or lead shields are applied to breasts, thyroid, gonads, and eyes whenever possible, especially in pediatric patients, to minimize their exposure to radiation.
Gonadal Shielding and Beam Collimation Policy
Gonadal shielding is an important radiation protection technique that can reduce the genetically significant dose (GSD) from diagnostic x•rays. The radiographic field shall be restricted to the area of clinical interest. Gonadal shielding of not less than 0.5 mm lead equivalent shall be used for patients the direct beam, except for cases in which this would interfere with the diagnostic procedure.
Purpose
The purpose is to minimize the radiation exposure to the gonads.
Scope
This policy applies to all radiographic or fluoroscopic exams and procedures using ionizing radiation, including portable units.
Implementation
Implementation of this policy is the responsibility of the technical staff.
Procedure
- Gonadal shielding shall be considered when the patient has a reasonable reproductive potential.
- Gonadal shielding shall be used when the gonads lie within or close to the direct x•ray beam. Examinations during which this is likely to occur include those involving the pelvis, hip, upper femur, abdominal, and lumbosacral spine examinations, intravenous pyelograms, abdominal scout films for barium enemas and upper GI series, and femoral angiograms. Gonadal shielding is not warranted during x•ray examinations of body parts at some distance from the gonads, i.e. the skull or extremities.
- The radiographic field shall be restricted to the area of clinical interest by the use of proper collimation.
- Gonad shielding should be used only when the clinical objectives of the examination will not be compromised. Thus, for male patients, gonad shielding can be used in the majority of radiographic examinations without obscuring visualization of adjacent structures.
Reviewed 9/92, 4/04, 7/07, 8/08 Revised 6/94, 6/95, 4/98, 3/10
Reference: Title 17 California Code of Regulations 30308
UCSF Medical Center Radiation Protection Committee
The Radiation Protection Committee at UCSF was established in 2007 with the overarching goal of reviewing radiation protection in all areas of the medical center. The Medical Center's Radiation Protection Committee meets every two months to discuss dose reduction strategies as well as providing a forum for discussion of safety issues that arise. In addition, routine meetings with clinical departments provide a forum for discussing optimal imaging techniques and indications to balance patient safety with optimal diagnostic regimens, so that the minimal radiation dose is used to acquire acceptable quality and diagnostic studies.
UCSF Department of Radiology and Biomedical Imaging Radiation Oversight Committee
In 2009, a departmental Radiation Oversight Committee was formed to oversee radiation-intense protocols and improve education regarding imaging algorithms to minimize exposure when possible, and specifically:
- Review and monitor CT radiation doses administered across all Departmental sites (Moffitt-Long, Mount Zion, China Basin, SFGH and SFVAMC).
- Formulate and implement dose reduction strategies (both with respect to modality utilization patterns and technical protocols), emphasizing the sections with high volumes where dose reduction would have the greatest impact, i.e., Abdominal Imaging, Thoracic Imaging, Neuroradiology, Pediatric Radiology, and Nuclear Medicine.
- Review and enhance educational tools and materials for physicians (both inside and outside the department) with respect to appropriate ionizing radiation utilization and radiation dose magnitude risks.
- Consider targeting certain referring physicians or groups for specific practice modifications, and develop audit tools to monitor and document such successes.
- Review and enhance radiation dose educational materials for patients.
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UCSF in comparison to other hospitals
Research conducted at UCSF shows that the radiation doses delivered by our CT scanners are comparable to those at other Bay Area hospitals [1].
- Smith-Bindman R, Lipson J, Marcus R, Kim KP, Mahesh M, Gould R, Berrington de González A, Miglioretti DL. Radiation dose associated with common computed tomography examinations and the associated lifetime attributable risk of cancer. Archives of Internal Medicine 2009; 169: 2078-86.
Contact Us
We take very seriously our obligation to our patients and staff to minimize the exposure to ionizing radiation and are available to answer questions or queries about this important issue. Please feel free to contact Dr. Roy Gordon, Chair of the Patient Safety committee at 415-353-1300, Dr. Fergus Coakley, Chair of the Radiation Protection Committee 415-353-1821, or Kathy Knoerl, Director of Operations, 415-353-1690.
