KACST Funded
Use of OSL Technology to Setup a Diagnostic Reference Level Center
مشروع مدعوم من مدينة الملك عبدالعزيز للعلوم والتقنية
استخدام تقنية الأو إس لإنشاء مركز تحديد مستوى الجرعات الاشعاعية التشخيصية
LAB Location
OSL Measurement LAB (Engineering Building 42 A, 2nd Floor, next to Biomedical Lab)
Research Team Members
PI: Nazeeh Alothmany, Phd, Biomedical Option at Electrical and Computer Engineering, KAU
Abdelhamid Saoudi, Phd, Medical Physicist, King Abdulaziz Medical City
Nurul Islam, Phd, Radiation Protection Committee, KAU
Abdulrahim Kinsara, Phd, Nuclear Engineering, KAU
Sameer Natto, Phd, Physicist, Om Alqura University
Dheya Alothmany, Phd, Nuclear Engineering, KAU
Dr Abdulraof Maymani, Radiologist, KAUH
Students and Engineers
Eng Ahmad Bashir
Eng Ahmad Jiman
Links
Learn about OSL Dossimetery
Saudi National Center for Radiation Protection
ملخص
تقيم وتمحيص الجرعات الإشعاعية للمرضى في قسمي الأشعة التشخيصية والطب النووي بمختلف الطرق والوضعيات والخوارزميات التصويرية يساعد على تقليل الجرعة الإشعاعية للمرضى بدون الإخلال بجودة الصورة. لذا نقترح إنشاء معمل لتقييم مستوى الجرعات المرجعية التشخيصية؛ والذي يراقب جرعات المرضى في المملكة العربية السعودية باستخدام تقنية حديثة متطورة (OSL ) تعتمد على خاصية الوميض المحفّز بالضوء في بعض المواد مثل الكربون المشوّب بأكاسيد الألمنيوم. وكان اختيار المادة ذات الخاصية المذكورة آنفاً اعتمد على وضوح تفوقها على غيرها من المواد ذات نفس الخاصية أو خاصية أخرى وهي الوميض المحفّز بالحرارة والتي تستخدم لنفس الغرض. أنظمة قياس الجرعات الإشعاعية بالوميض الضوئي تتحكم في متغيرات لتحصيل قراءة دقيقة ومتجانسة للجرعات على مجال واسع من القيم مقارنةً بأنظمة الوميض الحراري. ولقد تم استعراض نجاح عمل هذه التقنية لمختلف أنواع المقاييس مثل مقياس النقطة، مقياس الألياف البصرية، مقياس الأشعة المقطعية، والمقياس الفيلمي لمختلف وضعيات التطبيق الإشعاعي. كما أن تنوع أوضاع القراءة لمواد الوميض الضوئي مثل القراءة شبه الآنية، قراءة المحاكاة، والقراءة التراكمية والتي توسع تطبيقاتها لتشمل تقنية تصوير الأثداء، التصوير المقطعي، التصوير الإشعاعي الفيديوي، تصوير الأسنان، ومجال الطب النووي..
زيادةً على ما ذكر، إنّ إعداد معمل التقييم هذا سيساعد على تأسيس سلسلة من المقاييس على مستوى المملكة بالتعاون مع جميع أقسام الأشعة بهدف تقليل الجرعة الإشعاعية المتلقاة أثناء التشخيص الطبي. هدف هذا المعمل هو إعداد خوارزميات وقواعد ونصائح لأرقى وأفضل وآمن طرق التصوير الإشعاعي. كما أن من أهم الأهداف هو عمل تعاون دولي في مجال قياس الجرعات التشخيصية لمصلحة المملكة بما في ذلك بتطوير تقنية (الأو إس إل) وكشف الجرعات الزائدة على المرضى والعاملين وموافقة المقاييس العالمية في هذا المجال.
Abstract
Assessing patient dose in diagnostic imaging for both radiology and nuclear medicine field and for different imaging protocols will lead to the patient dose optimization without compromising image quality. It is proposed in this project to set up a Diagnostic Reference Levels (DRL) laboratory that monitor patients dose in the Kingdom of Saudi Arabia based on a new and innovative technology which uses the Optically stimulated luminescence (OSL) technique using the carbon doped aluminum oxide Al2O3:C material. The choice of OSL material is based on the clear advantage presented over other materials and methods using Thermoluminescence Dosimetry (TLD). OSL based dosimetry systems use controllable parameters to achieve precise and accurate dose reading over a wider dose range compared to TLD. It has been demonstrated that OSL could be used in different shape (point dose, fiber optic dosimeter, CT Strip Dosimeters “1D” or film Dosimeter “2D”) for different targeted applications. Also, versatility of OSL detector readout either in near real time mode by simultaneously irradiating and stimulating or integrated dose mode by stimulation after irradiation extends the application of OSL use to Mammography, Computer Tomography, Fluoroscopy, Nuclear Medicine and Radiotherapy.
Furthermore the setup of DRL will help establishing a series of measurements throughout the kingdom in collaboration with Radiologists, Nuclear Medicine practitioners, Oncologists, Medical Physicists in Radiology Departments of different hospitals and clinics aiming for patient dose reduction in diagnostic radiology without compromising clinical needs. The goal of a DRL, for predefined protocols and imaging modality, will provide recommendations and guidelines for Radiologists, Oncologists and nuclear medicine specialists for a safe and optimal use of radiation.
The purpose of this project is first to bring international collaboration and expertise in the field of diagnostic dosimetry, personnel monitoring with new and promising tools to KSA by developing a new innovative 21st Century OSL dosimetry service facility. Secondly, the goal of this project is to increase awareness about the unnecessary excess dose to patient and workers to meet international standards in radiation protection
Objectives
The proposed technique ‘Optically Stimulated Luminescence (OSL)’ based on the use of Al2O3:C would form the basis of 21st century innovative dosimetry tool in diagnostic imaging (e.g. X-ray, fluoroscopy; conventional and high radiological interventional procedures, CT, mammography and nuclear medicine), radiotherapy and personnel monitoring procedures. One of the major objectives is to bring international collaboration and expertise in the field of diagnostic dosimetry introducing a new promising tool to KSA and by developing a real-time OSL dosimetry reader for instantaneous dose assessment. The end-result will lead to develop and recommend Diagnostic Reference Levels (DRLs) values in collaboration with the radiologists and nuclear medicine practitioners, medical physicists on the basis of the results of nation-wide patient dose survey conducting in hospitals and clinics in the Kingdom as well as of international recommendations. It will also promote the attainment of narrower range of values of doses that represent a good practice for a specific medical imaging task.
The following are the envisaged quantities to be measured:
- Entrance air kerma or entrance surface dose in mGy for a given radiographic projection, (e.g. PA chest) with varying X-ray equipment, technique factors and image quality criteria.
- In mammography procedures Entrance Surface Dose (ESD) and Mean Glandular Dose (MGD) will be assessed by using phantoms and representative patients by OSL technique.
- To measure the integral dose to individuals from a series of representative patients of different groups (age, weight, sex, etc.) by using recently developed innovative OSL dosimeters (dot, strip and fiber optics types) and high sensitivity TLDs, ionization chamber and DAP.
- Real-time in vivo measurements of doses in radiotherapy by OSL technique
- Dose-area product in mGy.cm2 for a given type of fluoroscopic examination that has a well defined anatomical region of clinical study; type of equipment, technique factors and patient characteristics may differ within or among facilities. In interventional procedures, it intends to monitor whether the threshold doses for deterministic effects are being approached or exceeded.
- Dose length product in mGy.cm for a given type of Computed Tomography (CT) examination that has a well defined anatomical region of clinical study, with specific objectives, image quality criteria and technical factors; the CT systems may vary among different facilities.
- Administered activity in MBq for a given medical imaging task using a specific radiopharmaceutical, e.g. whole body scanning with 99mTc DTPA. The technical purpose, the image quality, the type of scanning equipment, technique factors and patient characteristics shall be considered.
- The statistical analysis of annual dose distributions of occupationally exposed workers and the specialists in radiology, nuclear medicine and interventional radiology will be used to calculate the Dose Constraints levels.
- The results of DRL will be compared with European Community Reference Levels.
In developing the DRL values in common diagnostic X-ray examinations, patient information and exposure parameters shall be taken into consideration.