Standard Operating Procedure TCRC Dual-Energy X-ray Absorptiometry (DXA)

Transcription

1 1. RELEVANCE a. This SOP outlines the instructions to completing Duel Energy X-Ray Absorptiometry (DXA) including: scanning, analysis, review and filing. 2. SCOPE a. This SOP applies to all TCRC RDs. 3. DEFINITIONS/ABBREVIATIONS a. Bone Mineral Density (BMD) is a measurement of the amount of bone mineral in bone tissue. This measurement is used clinically as an indirect indicator of osteoporosis and fracture risk. b. Certified Bone Density Technicians (CBDT) is a professional certification accredited in the field of bone densitometry for technologists who perform bone densitometry scans. The CBDT credential signifies that an individual has passed an examination that has been designed to meet established certification industry standards and best practices. c. Dual Energy X-Ray Absorptiometry (DXA) (also known as DEXA) scan is a non-invasive test, widely used and most thoroughly studied measurement BMD that provides an accurate estimate central or axial skeletal sites (spine and hip). Two x-ray beams of differing energy are used to calculate a 2-D measurement of areal BMD. Although, DXA scans are primarily used to measure BMD, the indirect measurement of total body composition and fat content is comparable to underwater weighing. d. International Society of Clinical Densitometry (ISCD) is the leading membership organization for professionals working to assess, monitor and treat skeletal health. 4. RESPONSIBILITIES a. All TCRC RDs are Certified Bone Density Technicians (CBDT) through the International Society of Clinical Densitometry (ISCD) within 2 years of employment. 1. Certification includes completion of the Essential Osteoporosis Course Offered by the ISCD, examination, and the submission of at least 100 DXA scans for review. 2. Certification ensures quality scans, ability to trouble-shoot and knowledge to assist in data interpretation for investigators. s are based on Hologic training manuals and specialized training (i.e. HSA, distal femur) for Hologic Horizon A. s are based on research findings and scientific evidence; and will be applied to assure quality outcomes. 3. ISCD DXA certificates will be maintained on file on the TCRC. 4. All TCRC RDs must complete annual CEUs to maintain CBDT certification. 5. Recertification through the ISCD is required every 5 years. b. TCRC DTs may be trained to assist with calibrating, positioning, and cleaning the DXA. c. It is the responsibility of the TCRC RDs to peer review scans prior to submitting completed DXA scans to the Study PIs. d. Completed scans will be provided to the study PIs. It is at the study PIs discretion to share data with the participant. 1

2 5. PROCEDURES Provided here is an abbreviated explanation of procedures for the DXA scans for additional information see: Hologic Reference Manual a. Calibration and Phantom Scanning 1. Lumbar spine phantom calibration is completed prior to first scheduled scan following Hologic protocol. Whole body calibration is completed every 10 days. 2. If two consecutive data points are outside the ±1.5% control limits, then a Hologic maintenance visit will be requested. 3. Weekly quality control for step phantom scans as an independent assessment of system calibration. 4. Additional phantom scans may be completed in line with specific protocol needs. 5. Plot and review data from calibration and phantom scans. 6. Plot values are stored in the Hologic programs QC folder. b. Maintenance and Preventative Maintenance 1. Preventative maintenance will be completed every 6 months at a minimum or as needed. 2. When the machine needs repair or service, Hologic should be contacted. 3. All maintenance reports will be filed in MNR digital drive (T Drive). c. Participant Preparation for DXA 1. DXA: Preparing for your visit document is available for study staff to provide to participants. 2. All participants will be asked to arrive in, or change into a metal / plastic free outfit. All metal including jewelry and eyeglasses must be removed. 3. Participants should not take a calcium supplement at least 4 hours prior to their visit. 4. If possible, participants should avoid scans that involve dye or contrast, or swallowing barium within 2 weeks of their DXA scan. If unavoidable, consider rescheduling DXA scan. 5. Height and weight are needed prior to DXA scan. These can be taken by TCRC RD/DT or provided by study team, as specified by the Doctor s Orders. 6. Participants will be asked DXA interview questions. 7. Pregnancy Point of Care Testing (POCT) (1) Urine POCT (for HcG) will be completed on all females, unless otherwise specified by the study MD/NP, prior to the DXA scan. (2) TCRC guidelines requiring no pregnancy testing under these conditions: girls at Tanner stage 1 or 2; women aged 55 years or older with no menses/spotting for 12 months (both conditions apply); or s/p hysterectomy or tubal ligation. Study MD/NP should specify POCT no applicable in these cases. (3) Refer to the TCRC Urine Point of Care Testing (POCT) SOP for details on completing and documenting POCT test. 2

3 d. Scan Positioning and Completion 1. Positioning will be completed in accord with the Hologic Reference Manual, HSA and distal femur procedures. 2. If any artifacts are present in the regions of interest for the scans or if any modifications are made for the scans, these will be documented in the Scan Details and on the M&NR flowsheet such as L4 Excluded due to hip artifact or patient reports h/o scoliosis/curvature of spine 3. AP Lumbar: For most volunteers, the default length settings for the spine scan will be appropriate. However, it is possible that, for a tall volunteer, this length may not be adequate to include all necessary points of interest. If, during the scan, it becomes apparent that the default length of the scan will not be adequate, adjust the scan length to 23.9 cm. 4. The TCRC RD/DT will remain with the participant at all times during the DXA scans. 5. The TCRC RD/DT will explain the procedure to the participant and position them on the table for the scans. 6. Efforts will be made to ensure the patients comfort within the confines of the scan requirements. If any scans cannot be completed due to patient discomfort or other reason, this will be documented in the medical record. e. Special Considerations 1. Certain subject populations, such as pediatric, older adults, high BMI, neurology, will require two DXA technicians for best and efficient scan completion. 2. High BMI Subjects: scanners are not capable of imaging extremely wide subjects, e.g. morbidly obese subjects or subjects with shoulder widths greater than 26 inches, which is the upper 95% confidence interval for shoulder width. In cases where the subject cannot be positioned entirely within the DXA field of view, some anatomical regions (typically shoulders, arms, hands, or hips) will not be measured. Volunteers will either be centered on the table or positioned so that the right arm is in the scan area depending on the protocol. It is up to the physician, investigator, or health care professional to determine whether the missing information in these anatomical regions adversely affects the DXA measurement. 3. The weight limit of the table is 450 pounds. 4. If a patient is >350 pounds, study staff will be notified that information may be inaccurate or may be unable to be mapped/analyzed. If a patient exceeds the weight limit, the forearm with the patient seated in a chair can be scanned for BMD. 5. Tall volunteers: If the volunteer is too tall, the head will be positioned in the scanner parameters and the feet will extend off the table, unless otherwise specified by a protocol. f. Radiation Exposure 1. Please refer to the Massachusetts Imaging - Radiation Safety RADIATION SAFETY POLICY located in Ellucid. 2. Site exposure reported in the array mode representing the maximum amount of radiation that a patient will receive. 3

4 Scan Site Dose (EDE) Adult Dose (EDE) Pediatric 5y PA lumbar Spine 1.3 mrem 4.8 mrem Proximal Femur 0.9 mrem 2.9 mrem Forearm >0.1 mrem >.1 mrem Whole body 0.8 mrem 1.1 mrem 3. Maximal Permissible Dose in the US*, excluding medical or dental 5,000 µsv 1,000 µsv (international standard) 50,000 µsv (technologist) *Values from The International Society for Clinical Densitometry 10 Sv = 1 mrem 4. Dosimeters for DXA technicians (1) Radiation exposure will be monitored annually or more frequently if the DXA equipment is changed. (2) Contact MGH Radiation Safety: Sean McCullough and Rex Woodleigh (3) Dosimeter readings will be on file in the office of the M&NR Director. 5. Massachusetts Department of Public Health (1) Annual - Radiation Control Program Certificate of Registration. (2) Posted in the DXA room (3) Expires annually in December. (4) Letter for Radiation Renewal is sent via mail to the M&NR Director. (a) Process invoice with CRC Administrator. 6. Consent Form (1) SPID consent form will outline radiation dose exposure as determined by MGH Radiation Committee. Within the IRB application, the PI must complete radiation exposure section on the IRB application. (2) DXA RDs will document: (a) Informed consent is current at time of testing. (b) At time of SPID review, the informed consent contains pertinent language on radiation exposure from DXA scans. g. DXA Scan Reviews/Reports/Archive 1. All DXA scans completed will be peer reviewed by a TCRC RD CBDT. 4

5 2. Scans will be saved as a PDF and provided to study teams via the MNR RFA. Study teams may contact their protocol RD to gain access to these drives. 3. Protocol TCRC RD may transmit scans to outside centers in line with the protocol. 4. Scans will be archived weekly. h. Precision 1. Precision for the hip and spine will be performed annually and/or after training new DXA technician(s). 2. will follow the ISCD assessment guidelines. 3. Precision analysis will be shared with PIs and DXA committee members. i. Documentation 1. In Epic, The TCRC RD will document which scans (if any) were completed and the participant s answers to the DXA interview questions 2. DXA scans will be provided to the study team. The TCRC will not enter scan data into Epic. j. Cleaning 1. After each subject, the linens will be changed. 2. Table and positioning tools will be wiped down with antibacterial wipes. 6. OPERATIONAL DOCUMENTS a. None 7. REFERENCE(S) a. DXA Preparing for Your Visit available in TCRC MNR RFA. b. Blake GM, Naeem M, Boutros M, Comparison of effective dose to children and adults from dual x-ray absorptiometry examinations. Bone 2006; 38: c. Lewis MK, Blake GM, Fogelman I. Patient dose in dual x-ray absorptiometry. Osteoporosis International 1994 Jan; 4(1): d. MGH Imaging Radiation Safety Radiation Safety Policy hospitalpolicies.ellucid.com/documents/view/