UW MEDICINE PATIENT EDUCATION BONE DENSITOMETRY CHINESE 骨質密度檢查 如何爲掃描做準備 骨質密度檢查用於評估你的骨頭健康情況和骨折風險 請閱讀此手冊, 以瞭解這項檢查的工作原理 如何爲此項檢查做準備 檢查如何進行 檢查過程的預期步驟, 以及如何獲取你的檢查結果 什麼是骨質密度檢查? 醫生使用 X 光來觀察和評估骨折和肌肉骨骼系統 ( 骨骼和肌肉 ) 的損傷 但是, 普通的 X 光不是檢查骨質疏鬆症 ( 骨質變薄 ) 或者測量 骨密度 (BMD) 的最好方法 要檢測骨質疏鬆症和精確地測量骨密度, 醫生使用一種造影技術, 稱爲雙能 X 光吸收計量法 (DXA) DXA 掃描是一種快速和無痛的檢查 最適合用於測量骨質流失 DXA 掃描通常用於測量脊柱底部和髖部的骨密度 但是, 如果你有以下情況, 則會改而對你的非慣用前臂進行掃描 : 患有甲状旁腺机能亢進 換過髖關節或做過脊柱融合術, 或者有另一原因不能對你的脊柱底部或髖部進行掃描 此項檢查是怎樣工 作的? DXA 掃描使用 2 種劑量很低的 X 光射線來測量骨密度, 1 種具有高能量, 另 1 種 具有低能量 然後將 BMD ( 骨密度 ) 輸進資料庫, 並給出 2 種分數 : T 分數 這個數值表示將你與一個同性別 ( 性別 ) 的青年人的顛峰骨質密度進行比較而計算出的你的骨質密度 進行 DXA 掃描時, 你將躺在一張有襯墊的掃 描床上, 讓感測器臂越過正在掃描的部位 第 1 頁, 共 3 頁 骨質密度檢查 UWMC Imaging Services Box 357115 1959 N.E. Pacific St., Seattle, WA 98195 206-598-6200
T 分數為 -1 以上屬於正常 T 分數爲 -1 和 -2.5 之間表示骨質減少, 這是骨質流失的第一階段 骨質減少意味著骨折的風險增加了 T 分數低於 -2.5 表示骨質疏鬆 骨質疏鬆通常意味著有較高的骨折 風險 Z 分數 這個數值表示將你與同齡組中其他與你身材與性別相同的人進行比較而計算出的你的骨質密度 如果你的 Z 分數低於 -2.5: 你患有繼發性骨質疏鬆症 你可能需要做更多的醫學測試 如何為檢查做準備? 吃你平常吃的食物 在檢查前至少 24 小時內切勿服用鈣補充劑 穿著寬鬆舒適的衣服 切勿穿著任何帶有金屬拉鏈或金屬鈕扣的衣服 告訴你的醫生, 如果你最近 : - 做過鋇餐檢查 - 注射過電腦斷層掃描 (CT) 或放射性同位數掃描的造影劑 如果你最近做過上述其中一種檢查, 你可能需要等 10 至 14 天才能做 DXA 檢查 如果你可能懷孕了, 必須告訴你的醫生或 X 光技師 此項檢查如何進行? DXA 檢查需要大約 10 分鐘, 取決於所用設備和掃描的身體部位 你可能被要求脫掉衣服, 穿上一件醫院的病人長袍 如果是掃描脊柱或髖部, 你將要躺在一張有襯墊的掃描床上 掃描床下面有 X 光射線源, 上面有一個感測器 然後, 技師將幫助你擺好掃描的位置 : 第 2 頁, 共 3 頁 骨質密度檢查 UWMC Imaging Services Box 357115 1959 N.E. Pacific St., Seattle, WA 98195 206-598-6200
- 如果是掃描脊柱, 可能會用一個有襯墊的箱子支撐你的雙腿, 使你的骨盆和脊柱底部保持平直 - 如果是掃描髖部, 技師會將你的雙腳用帶子綁在一個楔狀物上 你的雙腿將略微向內旋轉 感測器將慢慢越過掃描部位, 並在電腦螢幕上産生一個影像 如果是掃描前臂, 你可能要躺在掃描床上或坐在一張掃描椅上 前臂掃描只需大約 30 秒鐘 檢查中我會有何感覺? DXA 骨密度測定是一種無痛 無創的檢查 當你躺在掃描床上時, 可能會要求你在短時間內保持一個令你不舒服的姿勢, 以便讓感測器臂越過你的身體 在檢查期間, 你必須儘量保持不動 這有助於拍攝出清晰有用的骨頭 影像 做這種檢查無需使用麻醉 ( 令你入睡的藥物 ) 這項檢查發出的輻射非常低 我怎樣獲取結果? 放射師將不會與你討論檢查的結果 將由一名代謝性骨病專家或一名 持有放射專科特考文憑的放射師審查你的 DXA 檢查並解釋你的檢查 結果 然後將一份檢查報告發送給要求做此項檢查的醫生或你的家庭醫生, 或兩者 這些醫生然後根據需要, 和你一起制定出一個治療方案 檢查結果通常可在幾天內獲得 有問題嗎? 你的問題是很重要的 如果你有任何問題或顧慮, 請給你的醫生打電話 q UWMC 造影服務部 : 206-598-6200 q Harborview 造影服務部 :206-744-3105 University of Washington Medical Center Bone Densitometry Chinese - Traditional Published PFES: 03/2005, 05/2009, 01/2014 Clinician Review:01/2014 Reprints on Health Online: https://healthonline.washington.edu 第 3 頁, 共 3 頁 骨質密度檢查 UWMC Imaging Services Box 357115 1959 N.E. Pacific St., Seattle, WA 98195 206-598-6200
UW MEDICINE PATIENT EDUCATION Bone Densitometry How to prepare for your exam Bone densitometry is used to assess your bone health and fracture risk. Read this handout to learn about how this exam works, how to prepare for it, how it is done, what to expect during the exam, and how to get your results. What is bone densitometry? Doctors use X-rays to view and assess bone fractures and other injuries of the musculoskeletal system (skeleton and muscles). But, a plain X-ray is not the best way to screen for osteoporosis (thinning of the bones) or for measuring bone mineral density (BMD). To detect osteoporosis and accurately measure BMD, doctors use a form of imaging called dual-energy X-ray absorptiometry (DXA). A DXA scan is a quick and painless exam. It is ideal for measuring bone loss. DXA scans usually measure bone density in the lower spine and hips. But, your non-dominant forearm may be scanned instead if you: Have hyperparathyroidism Have had a hip replacement or spinal fusion, or there is another reason that your lower spine and hips cannot be scanned How does the exam work? The DXA scan uses 2 very low-dose X-ray beams, 1 with high energy and 1 with low energy, to measure bone density. The BMD is then put into a database and given 2 types of scores: T-Score This number shows the amount of bone you have compared to a young adult of your same gender (sex) with peak bone mass. For your DXA scan, you will lie on a padded table while a sensor arm passes over the area being scanned. Page 1 of 3 Bone Densitometry UWMC Imaging Services Box 357115 1959 N.E. Pacific St., Seattle, WA 98195 206-598-6200
A T-score above -1 is considered normal. A T-score between -1 and -2.5 shows osteopenia, the first stage of bone loss. Osteopenia means that there is an increased risk for fracture. A T-score below -2.5 shows osteoporosis. Osteoporosis usually means there is a high risk for fracture. Z-Score This number shows the amount of bone you have compared to other people in your age group who are your same size and gender. If your Z-score is below -2.5: You have secondary osteoporosis. You may need more medical tests. How should I prepare for the exam? Eat your meals as usual. Do not take calcium supplements for at least 24 hours before the exam. Wear loose, comfortable clothing. Do not wear any metal zippers or metal buttons. Tell your doctor if you recently: Had a barium exam Received a contrast material for a computed tomography (CT) or radioisotope scan If you have had one of these exams recently, you may need to wait 10 to 14 days before having a DXA exam. Tell your doctor or X-ray technologist if there is any chance you may be pregnant. How is the exam done? The DXA exam takes about 10 minutes, depending on the equipment used and the parts of your body that are scanned. You may be asked to undress and put on a hospital gown. If your spine or hips are being scanned, you will then lie on a padded table. The table has an X-ray source below it and a sensor above it. The technologist will then help position you for the scan: Page 2 of 3 Bone Densitometry UWMC Imaging Services Box 357115 1959 N.E. Pacific St., Seattle, WA 98195 206-598-6200
If your spine is being scanned, your legs may be supported on a padded box to keep your pelvis and lower spine flat. If your hips are being scanned, the technologist will strap your feet to a wedge. Your legs will be rotated slightly inward. The sensor will slowly pass over the area, making an image on a computer screen. If your forearm is being scanned, you may either lie down or sit in a chair. The forearm scan lasts only about 30 seconds. What will I feel during the exam? DXA bone densitometry is a painless, non-invasive exam. While you are lying on the table, you may be asked to hold an awkward position for a short time, while the arm of the machine passes over your body. You must stay as still as you can during the exam. This will help create a clear, useful image of your bones. You do not need to have anesthesia (medicine to make you sleep) for this exam. Radiation exposure from the exam is very low. Questions? Who interprets the results and how do I get them? The radiologist will not talk with you about the results. A metabolic bone disease specialist or a board certified radiologist will review your DXA exam and interpret your results. A report will then be sent to the doctor who ordered the exam or to your primary care provider, or both. These care providers will then work with you to create a treatment plan as needed. Results are usually ready within a few days. Your questions are important. Call your doctor or health care provider if you have questions or concerns. UWMC Imaging Services: 206-598-6200 Harborview Imaging Services: 206-744-3105 University of Washington Medical Center Published PFES: 03/2005, 05/2009, 01/2014 Clinician Review: 01/2014 Reprints on Health Online: https://healthonline.washington.edu Page 3 of 3 Bone Densitometry UWMC Imaging Services Box 357115 1959 N.E. Pacific St., Seattle, WA 98195 206-598-6200