摘要
目的测算Implagraphy牙颌面锥形束CT（CBCT）体模不同扫描体位的组织器官吸收剂量、当量剂量及有效剂量，为相应的防护措施提供客观依据。方法使用仿真成年男性头颈部体模及热释光剂量计，分别测量ImplagraphyCBCT下颌、上颌及颞下颌关节（TMJ）扫描时脑垂体、眼晶状体、腮腺、颌下腺、舌下腺、颅骨板障、下颌松质骨、颈椎松质骨、颊部皮肤、颈部皮肤、甲状腺、食管及口腔黏膜等组织器官的吸收剂量，计算眼晶状体、皮肤的当量剂量，及ImplagraphyCBCT不同扫描体位的有效剂量E1990及E2007。结果ImplagraphyCBCT各扫描体位的吸收剂量分别为：下颌扫描（0．99±0．09）-（12．85±0．09）mGy，上颌扫描（0．93±0．01）～（13．07±0．02）mGy，TMJ扫描（0．68±0．01）～（10．18±0．04）mGy，相同组织器官在不同扫描体位的吸收剂量的差异具有统计学意义（F=19．61～30992．27，P〈0．05）。在不同扫描体位，眼晶状体及皮肤的当量剂量分别为（1．11±0．07）～（5．76±0．06）mSv和（6．96±0．06）～（10．64±0．07）mSv，差异具有统计学意义（F=4473．02、9385．50，P〈0．05）。有效剂量层1990及E2007分别为：下颌扫描（191．35±1．53）和（325．17±2．58）μSv，上颌扫描（106．62±2．17）和（226．28±2．81）μSv，TMJ扫描（104．21±1．02）和（142．36±1．90）μSv。结论在牙颌面CBCT检查过程中，采用尽可能小的扫描视野、准确地扫描体位，正确使用铅胶帽、围领及防护镜等屏蔽措施，使X射线辐射照射保持在可以合理达到的尽可能低的水平。
Objective To evaluate the subject＇s absorbed dose, equivalent dose and effective dose. Methods The CBCT unit was Implagraphy and three scan projections were selected such as mandible, maxilla and temporamandibular joint （TMJ）. Thermoluminescent dosimeter tubes were used to record the absorbed dose at special positions in the head and neck region of an adult skull and tissue-equivalent phantom. 16 interested organs included pituitary, lens, parotid glands, submandibular glands, sublingual glands, diploe, spongy bone of the chin and cervical vertebra, skins of cheeks and nuchal region, thyroid and esophagus. The absorbed dose was measured in these organs, and then the effective dose （E199o, E2007 ） were calculated according to different ICRP tissue weighting factors. Results The absorbed dose of mandible, maxilla and TMJ scan varied from （0. 99 ±0. 09） to （ 12. 85± 0.09 ） mGy, （0. 93 ± 0. 01 ） to （13.07± 0. 02）mGy and （0.68 ±0. 01 ） to （10. 18 ± 0. 04）mGy. There was significant difference among the three scan projections （ F = 19. 61 - 30992.27, P 〈 0. 05 ）. The equivalent doses of lens and skin were （ 1.11 ± 0. 07 ） - （5.76 ± 0. 06） mSv and （6. 96± 0. 06 ） - （ 10.64 ± 0. 07 ） mSv. There was significant difference among the three scan projections （F = 4473.02, 9385.50, P 〈 0. 05）. The effective dose（ E1990, E2007 ） was [（191.35±1.53） , （325.17 ±2.58） μSv] for mandible scan, [（106.62 ±2.17） ,（226.28±2.81）μSv] for maxilla scan , [ （ 104. 21 ±1.02）, （ 142. 36 ± 1.90） μSv] for TMJ scan,respectively. Conclusions The valid measurement should be taken to reduce the subject＇ s dose such as a careful history and clinical examination before the performance of CBCT, the latest risk/benefit assessment, precise scan position, the shielding of thyroid as well as brain and the smaller volume size as well.
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
2012年第5期535-538,共4页
Chinese Journal of Radiological Medicine and Protection
关键词
锥形束CT
吸收剂量
当量剂量
有效剂量
Cone beam computed tomography
Absorbed dosage
Equivalent dosage
Effective dosage
