Quality Assurance in Radiotherapy and Dosimetry
- 1. Quality Assurance in Radiotherapy and Dosimetry Md. Shakilur Rahman, PhD Bangladesh Atomic Energy Commission “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 2. Radiation is classified as being either non-ionizing or ionizing. Non-ionizing radiation is longer wavelength/lower frequency lower energy. While ionizing radiation is short wavelength/high frequency higher energy. Ionizing Radiation has sufficient energy to produce ions in matter at the molecular level. Radiation “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 3. - Energy in the form of particles or waves - Emitted by nucleus of atom or orbital electron or Coulomb Field of the nucleus - Released in the form of electromagnetic waves or particles Concept of Ionizing Radiation 1896 Henri Becquerel discovered natural radiation - Uranium energy captured by phosphorus and X-Ray film, Marie Curie - student of Henri, determined the emissions were radiation and found the radioactive element - Radium and Polonium. She won two Nobel Prizes in two fields (1903 and 1911) one with HB and one with her husband 1895 X Rays discovered by Roentgen 1896 First skin burns reported 1896 Becquerel: Discovery of radioactivity 1897 First cases of skin damage reported 1998 First use of X Rays in the treatment of cancer 1902 First report of X Ray induced cancer 1911 First report of leukaemia in humans and lung cancer from occupational exposure 1911 94 cases of tumour reported in Germany (50 being radiologists) α ray Nucleus of Helium (He) β ray High Energy Electron γ ray Photon (Electromagnetic Ray) X ray Photon (Electromagnetic Ray) n ray Particle Beam “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 4. Applications of Radiation in Medicine Diagnostic & Nuclear Medicine X-rays Mammography CT PET Fluoroscopy etc. Radiation Therapy Teletherapy Deeptherapy X-ray Linac Proton Therapy BNCT Brachytherapy etc. “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 6. In the 1960’s almost 25% of the global cancer burden was diagnosed in low-income and lower-middle income countries. In 2010 nearly 55% of the global cancer burden is found in these countries. In 2020 it will rise to around 70%. The developing world will suffer the most. By 2030 over 13 million people will die from cancer every year. Almost 9 million of these deaths will be in developing countries. By 2050 at present growth rates, your chances of contracting cancer in your lifetime will be 50 to 60%. The cancer rate will rise from 0.6 to 2.2 million per year. Cancer kills more people globally than tuberculosis, HIV, and malaria combined. 85 million people will die of cancer over the next 10 years unless nations take action to prevent these deaths. Low and middle income countries will be hit the hardest. Cancer is an important health issue and be a major determinant of the human and economic wealth in a country Background: Cancer “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 7. BACKGROUND : CANCER IN BANGLADESH In Bangladesh, it is estimated incidence of cancer is 1.6 million which would be 2.1 million by 2030. According to the BBS, cancer is the sixth leading cause of death. International Agency for Research on Cancer has estimated cancer-related death rates in Bangladesh to be 7.5% in 2005 and 13% in 2030. Bangladesh has developed a National Cancer Control Strategy and Action Plan with the aim of delivering a universal, quality-based and timely service. Cancer prevention through tobacco control, health promotion and vaccination program, cancer early detection program for oral cavity, breast and cervix has initiated. Cancer site % Cancer site % Lungs 25.5 Breast 25.6 Lymph node 7.4 Cervix 21.5 esophagus 5.9 Lung 5.6 Larynx 5.4 Lymph node 4.1 Stomach 5.1 esophagus 3.4 Liver 3.3 Ovary 3.3 Tongue 2.6 Gall bladder 2.7 Skin 2.5 Stomach 2.6 Rectum 2.3 Rectum 1.8 Others 40 Others 29.4 Top Malignancies in Bangladesh “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 8. “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 9. Treatment of Cancer Surgery Chemotherapy Radiotherapy (60-70%) Cell based Immunotherapy Gene Therapy “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 10. Radiotherapy and Cancer Radiotherapy is the procedure by which intentionally high radiation dose is delivered to the tumor This is main mode of treatment of cancer patients about 60-70% of the cancer patients are treated with radiotherapy Radiotherapy is the clinical use of ionizing radiation for cancer treatment to control malignant cells. Radiotherapy is the treatment modality where intentionally high radiation dose delivered to the patients. It works by damaging the DNA within cancer cells and destroying their ability to reproduce. target Critical organs Beam directions Patient Radiation therapy is used two different ways : To cure cancer: – Destroy tumors that have not spread to other body parts. – Reduce the risk that cancer will return after surgery or chemotherapy. To reduce symptoms: – Shrink tumors affecting quality of life, like a lung tumor that is causing shortness of breath. – Alleviate pain by reducing the size of a tumor. “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 11. Types of Radiotherapy Radiation therapy can be delivered two ways; externally and internally. External beam radiation therapy delivers radiation using a linear accelerator, 60Co or radiation beam from source outside the body. Internal radiation therapy, called brachytherapy or seed implants, involves placing radioactive sources inside the patient. “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 12. Radiotherapy Equipment Deep-therapy X-ray, IMRT based Cobalt unit and Linear Accelerator True Beam Accelerator, Proton beam, Cyber-Knife
- 13. Basic Concept of Biological Effects of Ionizing Radiation Stochastic Effects o Where the severity of the result is the same but the probability of occurrence increases with radiation dose, e.g., development of cancer o There is no threshold for stochastic effects o Examples: cancer, hereditary effects o Hereditary: (genetic) - assumed stochastic incidence, however, manifests itself in future generations Deterministic Effects o Where the severity depends upon the radiation dose, e.g., skin burns o The higher the dose, the greater the effect o There is a threshold for deterministic effects o Examples: skin burns, cataract Due to cell changes (DNA) and proliferation towards a malignant disease Severity (example cancer) independent of the dose No dose threshold - applicable also to very small doses Probability of effect increases with dose Generally occurs with a single cell e.g. Cancer, genetic effects Dose Probability of effect Stochastic Effects of Ionizing Radiation “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 14. Thresholds for Deterministic Effects (Single exposure) Tissue or Organ and effect Thresholds (Sv) Testis: Temporal Sterility Permanent Sterility 0.15 3.5 ~ 6.0 Ovary: Permanent Sterility 2.5 ~ 6.0 Lens of eyes: Detectable opacity Cataract (Visual impairment) 0.5 ~ 2.0 5.0 Bone marrow: Depression of hematopoiesis 0.5 Effect Region Exposed Leukemia red bone marrow Lung Cancer trachea, bronchial tubes, alveoli Breast Tumor mammary gland Sterility reproductive gland （ovary, testis） Hereditary Effect reproductive gland （ovary, testis） Embryonic Malformation 2~8 weeks embryo Region Exposed vs. Arising Effects “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 15. Radiation Burn Skin graft 13wk >21wk 3 wk 4wk 11wk “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 16. Ionizing radiation interacts at the cellular level: Ionization Chemical changes Biological effect Stochastic effects develop due to mutation effect of low dose radiation; it is observed that cancer of different location appears above different dose ranges, the severity of the effect does not depend on the dose. Genetic effects might result in lesions of chromosomes in the germinal lineage Deterministic effects develop due to cell killing by high dose radiation, appear above a given threshold dose, which is considerably higher than doses from natural radiation or from occupational exposure at normal operation Radiation effects H-O-H H+ + OH- (ionization) H-O-H H0+OH0 (free radicals) “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 17. The main mechanism of radiotherapy The radiations produce ionization of the tissues along its path while passing through the human body. When the cells are ionized, free radicals and reactive oxygen species (ROS) form. Free radicals are simply atoms, molecules, or ions with unpaired electrons, and ROS is a subset of free radicals that involve oxygen. These agents are very chemically reactive due to their free electron. Due to this high reactivity, free radicals and ROS are likely to attack the covalent bonds of the DNA and typically occur in chains. Enough injury in the cell will result in cell death. At the same time, if enough DNA is damaged, the cells will be unable to replicate. Thus, when the radiation targets the tumor cells, the affected cells will die or be unable to proliferate; effectively reducing or eliminating the cancer. These radiation damages can be repaired efficiently in normal cells by the presence of enzyme ribonuclease, but the same enzyme is deficient in cancer cells. direct ionization of the DNA, ≈ 15% indirect ionization of the DNA, ≈ 85% 1 Gy of RT causes approximately 105 ionizations >1000 damages to DNA bases 1000 single strand breaks 20-40 double strand breaks (DSBs) Kills approximately 30% of human cells, as a consequence of efficient DNA repair “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 18. Reference: What is Free Radical? Nucleus Electron Unpaired Electron Unpaired Electron Strong Oxidizing Power Free Radical Radiation Water (H2O) Hydroxyl Radical To be stable, a Free Radical takes an electron from other molecules. A Free Radical has strong oxidizing power since it takes an electron from other molecules. (Oxidizing Other Substance) Super Oxide Radical (Active Oxygen), Hydroxyl Radical (OH’) “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 19. Effect of radiation : DNA Level Ionization by radiation DNA strand break DNA repair complete incomplete Recovery of normal function Possibility to future somatic or hereditary effect
- 20. High resolution IMRT Multileaf Collimator Dynamic MLC and IMRT 1960’s 1970’s 1980’s 1990’s 2000’s Cerrobend Blocking Electron Blocking Blocks were used to reduce the dose to normal tissues MLC leads to 3D conformal therapy which allows the first dose escalation trials. Computerized IMRT introduced which allowed escalation of dose and reduced compilations Functional Imaging IMRT Evolution evolves to smaller and smaller subfields and high resolution IMRT along with the introduction of new imaging technologies The First Clinac Computerized 3D CT Treatment Planning Standard Collimator The linac reduced complications compared to Co-60 Evolution of Radiotherapy “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 21. 60Co Tele-therapy Machine “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 22. A linear accelerator is a device that uses high Radio‐Frequency (RF) electromagnetic waves to accelerate charged particles (i.e. electrons) to high energies in a linear path, inside a tube like structure called the accelerator waveguide. The x-rays are generated by a linear accelerator (linac). The linac fires high energy electrons at a metal target and when the electrons strike the target, x-rays are produced. The x-rays produced are shaped into a narrow beam by movable metal shutters. Linear Accelerator “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 23. 23 Proton Beam Radiotherapy Proton are produced from ion source, positively charged particle from cyclotron It has Bragg peak due to cross-section increases energy decreases Works as pencil beam scanning or narrow beam Very complex type of tumor can be irradiated with high precision
- 24. Boron Neutron Capture Therapy (BNCT) 1. Inject boron-10 non toxic compound known as Boronophenylalanine (BPA) 2. Cancer cell has high demand on amino acid, BPA works as amino acid transporter 3. Epithelial neutron (0.3 eV-10 keV) from cyclotron by proton-Be reaction or from nuclear reactor BNCT: Brain, Head-neck and Melanoma “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 25. Types of external beam radiation therapy Three-dimensional conformal radiation therapy (3DCRT) Common type of EBRT The radiation therapy team use CT scans to map out the precise location of the cancer and the normal organs that need to be protected. The radiation beam is then shaped (conformed) so that the cancer receives most of the radiation, and surrounding tissues receive much less. Used to treat many different types of cancer. Intensity-modulated radiation therapy (IMRT) Highly accurate type of conformal radiation therapy. Shapes and divides multiple beams of radiation into tiny beams (beamlets) that vary in dose. Used for most cancer types, especially for curative treatment. Volumetric modulated arc therapy (VMAT) is the specialized forms of IMRT that deliver radiation continuously as the treatment machine rotates around the body “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 26. Image-guided radiation therapy (IGRT) Uses a treatment machine that takes x-rays or CT scans at the start of each session to check that you are in the correct position for treatment. Markers (usually grains of gold) may have been inserted into or near the cancer so they can be seen in the x-rays or scans and used to guide positioning. Positioning can be very finely adjusted to deliver treatments with millimetres accuracy. Commonly used with many types of radiation therapy to any area of the body. May also be recommended for areas likely to be affected by movement, such as the lungs from breathing. Stereotactic radiosurgery (SRS) and stereotactic radiation therapy (SRT) Specialized type of radiation therapy. Combines many small radiation fields to give precisely targeted radiation. SRS is delivered as one high dose and SRT is delivered as a small number of high doses. Used to treat small cancers in the brain while minimizing the radiation reaching healthy brain tissue. A custom mask is worn to keep the head still. Despite the name, SRS is not surgery and does not involve any surgical cuts.
- 27. History of radiotherapy in Bangladesh The first radiotherapy in Bangladesh was introduced in 1947 by a 300 kV x-ray machine that was installed for the treatment of cancer patient at Kumudini Hospital in Mirzapur, Tangail The second 60Co machine was installed in 1959 at DMCH. A deep therapy x-ray machine was installed at CMCH in 1964. Beside the radiotherapy units, few manual Ra-226 are installed “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 28. Radiotherapy Facilities in Bangladesh: Government Oncology Centers Sl. No Radiotherapy center 60Co LINAC B’therapy Simulator 1. National Institute of Cancer Research & Hospital 02 04 01 02 2. Dhaka Medical College and Hospital 01 01 01 01 3. Bangabandhu Sheikh Mujib Medical University - 01 01 - 4. Chittagong Medical College and Hospital 01 - 01 01 5. Rajshahi Medical College and Hospital 01 - 01 - 6. Rangpur Medical College and Hospital 01 - - - 7. Sylhet MAG Osmani Medical College & Hospital 01 - - - 8. Sher-e-Bangla Medical College and Hospital 01 - 01 - 9. Mymensingh Medical College and Hospital 01 - - - 10. Shaheed Ziaur Rahman Medical College & Hosp. - 01 01 - 11. Bangladesh Atomic Energy Commission, Dhaka - 01 - 01 12. Combined Military Hospital, Dhaka - 01 01 01 Total 09 09 08 07 “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 29. Sl. No. Name of Center 60Co LINAC B’therapy Simulator 1 Delta Hospital Limited 02 03 01 01 2 United Hospital Ltd. - 02 01 01 3 Khawja Yunus Medical College and Hospital - 03 01 02 4 Square Medical College and Hospital - 01 - 01 5 Ahsania Mission Cancer and General Hospital 01 02 01 01 6 North-East Medical College and Hospital - 01 01 01 7 Enam Medical College & Hospital - 01 01 01 8 Apollo Hospital Ltd. - 01 01 01 Total 03 14 07 09 Private Oncology Centers “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 30. Meet the Radiotherapy Treatment Team Radiation Oncologist The doctors who oversee the radiation treatment therapy Medical Radiation Physicist Ensures the treatment plans are properly tailored for each patient Dosimetrist Works with the radiation oncologist and medical physicist to calculate the proper dose of radiation given to the tumor Radiation Therapist Administers the daily radiation under the doctor’s prescription and supervision Radiation Technologist Deliver the dose to patient as per prescription and planning Radiation Oncology Nurse Cares for the patient and family to provide education, emotional support and tips for managing side effects “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 31. Interaction of Photon with Tissue “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 32. Management of QA Program Radiation oncologists: consultations, dose prescriptions, on-treatment supervision and evaluations, treatment summary reports, follow-up monitoring and evaluation of treatment outcome and morbidity. Medical physicists specification, acceptance, commissioning, calibration and quality assurance of all radiotherapy equipment. measurements of beam data, calculate doses and plan the treatment. take care of radiation safety and radiation protection in the radiotherapy department. Radiotherapy technologists: Clinical operation of simulators, computed tomography (CT) scanners, treatment units, etc.; Patient set-up and dose delivery; Documenting treatment and observing the clinical progress of the patient and any signs of complication. Undertaking daily quality assurance of treatment equipment in accordance with physics quality assurance procedures and protocols; Construction of immobilization devices, etc. Dosimetrists: Accurate patient data acquisition; Radiotherapy treatment planning; Dose calculation; Patient measurements. “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 33. QA parameters of a Medical Linac
- 34. Traceability to international standards “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 35. 5% too low - may result in clinically detectable reduction in tumour control (e.g. Head and neck cancer: 15%) To normal tissues: 5% too high - may lead to significant increase in normal tissue complication probability = morbidity = unacceptable side effects The outcome of radiotherapy highly depends on how precisional dose deliver to the tumor Sources of uncertainty: Absolute dosimetry/calibration Relative dosimetry (%depth dose, profiles, output factors) Treatment planning (estimated uncertainty of the order of 2%) Machine performance on the day ( 2%) Patient set-up and movement ( 3%) Medical linear accelerator (LINAC) and Teletherapy (60Co) is a potential source of photon beam in curative and palliative treatment modality for a variety of cancers. The effectiveness of the output of treatment is highly dependent on the radiation dose being delivered to the treatment site. Clinical data consideration lead to generally agreed recommendations, ICRU report-24 (1976) for at least accuracy of ±5%. This requirement implies that dose measurement should be accurate with ±3.5%. Importance of Radiotherapy Dosimetry “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 36. IAEA 277: Absorbed Dose Determination in External Beam Radiotherapy (1987) based on air kerma IAEA 398: Absorbed Dose Determination in External Beam Radiotherapy (2000) DIN 6800-2: German Protocol for High Energy Photon and Electron Beam for Therapy level Dosimetry AAPM TG-51: Protocol for clinical reference dosimetry of high- energy photon and electron beams (1999) Dosimetry protocols or codes of practice state the procedures to be followed when calibrating a clinical photon or electron beam. The choice of which protocol to use is left to individual radiotherapy departments or jurisdictions. Dosimetry protocols are generally issued by national, regional, or international organizations. Dosimetry Protocols “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 37. QA of Dosimetry : Intercomparison Program IAEA/WHO TLD INTERCOMPARISON PROGRAM Dosimetry intercomparison is designed to establish the accuracy and the precision of dosimetry at given level in the dosimetry chain and to assess consistency between the centers. To investigate the accuracy of output dose used for the treatment of patients at oncology centers To reduce uncertainties involved in the measurement of absorbed dose to water To build-up the confidence of hospital physicist on QA of dosimetry Traceability of national and international standard for absorbed dose measurement “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 38. No. center Oncology centers Year Treatment unit No. Center No. of beam 07 MAG Osmani Medical College & Hospital, Sylhet 2011 FYC-260 60Co 10 Rajshahi Medical College & Hospital, Rajsahi FYC-260 60Co Rangpur Medical College & Hospital, Rangpur FYC-260 60Co Square Hospital Ltd., Dhaka Varian 2300CD 6 MV United Hospital Ltd., Dhaka Varian Clinac 2DMX 6MV, 15 MV National Institute of Cancer Research Hospital, Dahka Varian 2100CD 6MV, 60Co Khwaja Yunus Ali Medical College & Hospital, Sirjagonj Elekta Synergy 6 MV (2) 03 Khwaja Yunus Ali Medical College & Hospital, Sirajgonj 2013 Elekta Synergy 4 MV, 6 MV (2), 15 MV 10 Dhaka Medical College & Hospital, Dhaka Varian 2100CD, Elite 80 6 MV, 15 MV, 60Co Square Hospital Ltd., Dhaka Varian 2300D 6 MV, 10 MV 05 Ahsania Mission Cancer and General Hospital, Dhaka 2015 Elekta Platform 4 MV, 6 MV, 15 MV 14 Dhaka Medical College & Hospital, Dhaka Varian 2100CD, Elite 80 6 MV, 15 MV Khwaja Yunus Ali Medical College & Hospital, Sirajgonj Elekta Platform 4 MV, 6 MV , 15 MV National Institute of Cancer Research Hospital, Dhaka Varian 2100CD 6 MV, 10 MV, 15 MV United Hospital Ltd., Dhaka Varian Clinac DMX, Varian True Beam 6MV (2), 15 MV Hospital level intercomparison program
- 39. No. center Oncology centers Year Treatment unit No. center Number of beam 01 North-East Medical College and Hospital, Sylhet 2016 Varian Clinac iX 6 MV, 15 MV 02 05 Enam Medical College & Hospital, Savar, Dhaka 2017 Elekta Synergy #154138 6 MV, 10 MV, 15 MV 14 National Institute of Cancer Research Hospital, Dhaka Varian Clinac 2100 C/D #5550 Varian Clinac 2100 C/D#3186 6 MV, 10 MV 15 MV Khwaja Yunus Ali Medical College & Hospital, Sirajgonj Elekta Synergy S #151836 4 MV, 6 MV, 15 MV Square Hospital Ltd., Dhaka Varian Clinac DHX#4526 6 MV, 10 MV United Hospital Ltd., Dhaka Varian True Beam #1519 Varian Clinac DMX#4943 6 MV, 15 MV 6 MV 04 Ahsania Mission Cancer and General Hospital, Dhaka 2018 Elekta Platform Uqinox 80 6 MV, 15 MV, 60Co 09 Apollo Hospital Ltd., Dhaka Elekta Versa 6 MV, 15 MV Square Hospital Ltd., Dhaka Varian Clinac iX #5982 6 MV, 15 MV United Hospital Ltd., Dhaka Varian Clinac DMX #4943 Varian TrueBeam #1519 6 MV, 15 MV Hospital level intercomparison program “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 40. Beams Range (1%) Range (2%) Range (3%) Range (4%) Range (5%) Range ( 5%) 60Co 1 1 2 1 - - 4 MV - 3 - - - 1 6 MV 5 6 7 3 2 4 10 MV 1 1 2 1 - - 15 MV 6 5 2 1 1 3 Total 59 13 16 13 6 3 8 Intercomparison Program : Result The acceptance limit (±5%) with an uncertainty of ±1.8% (k=1) The reason of discrepancies is determined and correction is made by onsite visit by SSDL personnel. The intercomparison performed is a successful step from the point of view in improving the dosimetry situations in hospitals. Discrepancy (large value) : Error in calculating absorbed dose IC calibration factor “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 41. Reference Study Beam No. Ratio : Mean SD Wochos et al., 1982 USA 2319 1.00 0.042 Davis and Falr., 1992 Switzerland 25 0.995 0.005 Hanson et al., 1993 Europe 357 1.007 0.040 Dutriex et al.,1993 EC 125 0.970 0.095 Huntley et al., 1994 Australia 30 0.993 0.033 Izewska J. et al., 1995 Poland 22 1.004 0.038 Nisbet A. et al., 1998 Ireland 13 1.002 0.012 Rassiah P. et al., 2004 Malaysia 12 1.027 0.031 Rahman, M. S. et. al., 2019 Bangladesh 59 1.011 0.029 Results : Dose Ratio Ratio = Measured Mean Dose (IAEA)/User Stated Dose “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 42. Secondary Standard Dosimetry Laboratory (SSDL) To provide dosimetry services as per international protocol To provide Quality Assurance (QA) services of Dosimetry as per international traceable system To Provide calibration services of dosimetric equipment such as electrometer, ionization chamber etc. Work as a link between field radiotherapy centers and international organization IAEA and WHO to ensure the quality of radiotherapy treatment QA and QC of diagnostic radiology such as X-ray, Mammography, fluoroscopy etc. Calibration services of Radiation Protection equipment such as survey meter, pocket dosimeter, contamination meter, personnel dosimeter etc. Dosimetry Services Calibration of Ionization chamber electrometer QA/QC of radiotherapy units Traceability of radiotherapy unit according to international system
- 43. Reference Standard of SSDL, Bangladesh Atomic Energy Commission NPL : National Physical Laboratory PTB: Physikalisch-Technische Bundesanstalt NIST : National Institute of Standards and Technology IAEA: International Atomic Energy Commission “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 44. 80 Laboratory in 67 member states As a link between IAEA and radiotherapy centers for radiotherapy dosimetry and QA Calibration and standardization of radiotherapy equipment SSDL, Member of IAEA and WHO “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 45. Objective : IAEA/WHO SSDL Network The IAEA/WHO SSDL Network is an association of national SSDLs that have agreed to cooperate in promoting the objectives of that Network under international auspices. Its objectives are: Accuracy: to provide dosimetry services and create and distribute knowledge in radiation dosimetry in order to improve the accuracy level in dose measurements; Traceability: to establish and facilitate links between end users of dosimeters, the SSDL members; Consistency: to promote international recommendations on methods applied for calibration and performance of dosimetry in order to achieve consistency of measurements in all countries; IAEA/WHO SSDL Network
- 47. “Training Course on Radiation Protection for Radiation Workers and RCO’s of BAEC” Training Institute, Savar, Dhaka 26 October 2021
- 48. COMPUTER OPERATED X-RAY /GAMMA CALIBRATOR SYSTEM AND WBC AT SSDL
- 49. Thank you for your patience