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[P006] DRL’s in mammography: Results from 3 dose audits
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Abstracts / Physica Medica 52 (2018) 99–187
[P004] Measurment of entrance surface dose during chest X-ray examinations in neonatal intensive care unit using OSL and TLD dosimeters Mousa Bakkari *, Khaled Soliman Prince Sultan Military Medical City, Medical Physics Department, Riyadh, Saudi Arabia ⇑ Corresponding author. Purpose. Pediatric patient are known to have higher sensitivity to exposure to radiation. Therefore monitoring of radiation doses received by neonatal patients in our hospital is of primary importance element of our patient safety program in diagnostic radiology. We are proposing to measure the entrance surface dose (ESD) using OSL dosimeters due to their higher sensitivity and fast analysis in comparison with TLD both used for occupational dose monitoring at our institution. Methods and materials. Entrance surface dose was measured using the IAEA TRS-457 dosimetry protocol. Measured entrance surface dose using neonatal phantom and OSL dosimeters. The X-ray beam is the one produced by a portable X-ray machine routinely used in the hospital in ICU set up. We have used a neonatal body phantom (Model: 610 GAMMAX) to simulate the patient body. Both OSL and TLD readings were cross checked using a diagnostic X-ray shadow free PTW ionization chamber model: SFD34060 coupled to an electrometer model: UNIDOS E, linear calibration curves were obtained for the OSL and TLD. Results. The average measured ESD using the OSL and the TLD were 66 and 70 lGy respectively. The OSL were found suitable to conduct ESD measurements during chest X-ray exam for the neonatal patient. The obtained patient dose measurement will serve as an indicator of quality and patient safety standard in diagnostic radiology services. Conclusion. The measured values are within internationally published data. The study serves as a benchmark to our clinical practice against international diagnostic reference levels (DRL) in pediatric radiology. https://doi.org/10.1016/j.ejmp.2018.06.337
[P005] How much of patient dose is unjustified in CT head and abdomen exams? Evangelia Papageorgiou a,*, Vassiliki Georgopoulou b, Spyros Papadopoulos b a Hippokratio General Hospital of Thessaloniki, Medical Physics, Thessaloniki, Greece b Hippokratio General Hospital of Thessaloniki, Radiology, Thessaloniki, Greece ⇑ Corresponding author.
Purpose. Justification of medical exposures, especially of the high dose CT exams, should be fully implemented. The purpose of this study was the investigation of the unjustified CT head and abdomen exams and the evaluation of patient doses in a tertiary Greek hospital. Methods. Two radiologists reviewed and evaluated the justification of 209 CT Head and 283 CT Abdomen referrals based on the American College of Radiation Appropriateness CriteriaÒ and medical expertise. Patient status (emergency or not) and diagnostic outcome (positive/negative) were recorded. Effective doses were calculated based on Dose-Length-Product indications. Results. Sixty (29%) of the Head examinations were considered unjustified and could have been replaced by MRI or not a radiologi-
cal examination was needed, referred mainly for minor head trauma and headache. Sixty-eight (24%) of the Abdomen examinations were considered unjustified and could have been replaced by MRI &/ US or other type of examination, referred mainly for malignancy screening and abdominal pain. Thirty-seven of the Head and 37 of the Abdomen unjustified exams had negative outcome. The odds of having negative outcome for the unjustified exams compared with the justified ones were twofold (p < 0.0001). More unjustified examinations were referred for the non-emergency patients (p < 0.0001). Collective dose was 10.1 manSv for the Head exams of which 1.7 manSv were unjustified and negative and 71.4 manSv for the Abdomen exams of which 9.4 manSv were unjustified and negative. Conclusions. The non-implementation of referral criteria by clinicians for CT Head and Abdomen exams leads to a nearly 14% of unnecessary patient doses. https://doi.org/10.1016/j.ejmp.2018.06.338
[P006] DRL’s in mammography: Results from 3 dose audits Ana Roda a,*, Inês Santos b, Ana Maria Lopes b, Idílio Filipe Gomes b, Maria do Carmo Lopes a a Instituto Português de Oncologia de Coimbra Francisco Gentil, Epe, Medical Physics Department, Coimbra, Portugal b Instituto Português de Oncologia de Coimbra Francisco Gentil, Epe, Radiology Department, Coimbra, Portugal ⇑ Corresponding author.
Purpose. We compare the results of 3 dose audits (2013, 2015 and 2017) for bilateral mammography screening exams performed in a full field digital mammography unit GE Senographe DS. We estimated the average entrance surface dose (ESD) for a sample of at least 50 standard breasts. The results were compared with the European DRL - ESD of the 3rd quartile of the dose survey. We estimated average absorbed dose to the glandular tissue within breast (AGD) for a wide range of breast thicknesses, and converted it into effective dose. Data was presented to the staff to induce a process of optimization as team effort. Methods. For each dose audit we selected a sample of more than 150 bilateral mammography screening exams. The percentage glandularity was determined using the qualitative method described by Byng (1994) and compared with Dance (2000) empirical formula. AGD was determined from measurements of the output and exposure data using appropriate conversion factors from IAEA (2007), Dance (2000), Dance (2009). Effective doses were determined using ICRP 103 breast tissue weighting factor 0.12. Results. Results (2013): ESD = 5.8 mGy for cranio caudal (CC) and ESD = 6.1 mGy for medio lateral oblique (MLO) projections. These results are considerably below the European DRL’s (10 mGy). E ranged from: E = 0.28 mSv for small breasts (34.5 ± 4.5 mm) to E = 0.69 mSv for very large breasts (84.5 ± 4.5 mm) with larger compressed breast thickness associated with a higher AGD (E); Results (2015): around 30% increase in DRLs: ESD = 8.6 mGy CC and ESD = 8.7 mGy MLO; E ranged from E = 0.38 mSv for small breasts (34.5 ± 4.5 mm) to E = 0.75 mSv for very large breasts (84.5 ± 4.5 mm); Results (2017): within 5% of 2013. Conclusions. The 30% increase in the dose results in 2015 resulted from the increased use of Contrast Enhanced Automatic Optimization of Parameters (AOP CNR) mode. This action was investigated and corrected. Dose audits are important part of a quality assurance program. https://doi.org/10.1016/j.ejmp.2018.06.339
Abstracts / Physica Medica 52 (2018) 99–187
[P004] Measurment of entrance surface dose during chest X-ray examinations in neonatal intensive care unit using OSL and TLD dosimeters Mousa Bakkari *, Khaled Soliman Prince Sultan Military Medical City, Medical Physics Department, Riyadh, Saudi Arabia ⇑ Corresponding author. Purpose. Pediatric patient are known to have higher sensitivity to exposure to radiation. Therefore monitoring of radiation doses received by neonatal patients in our hospital is of primary importance element of our patient safety program in diagnostic radiology. We are proposing to measure the entrance surface dose (ESD) using OSL dosimeters due to their higher sensitivity and fast analysis in comparison with TLD both used for occupational dose monitoring at our institution. Methods and materials. Entrance surface dose was measured using the IAEA TRS-457 dosimetry protocol. Measured entrance surface dose using neonatal phantom and OSL dosimeters. The X-ray beam is the one produced by a portable X-ray machine routinely used in the hospital in ICU set up. We have used a neonatal body phantom (Model: 610 GAMMAX) to simulate the patient body. Both OSL and TLD readings were cross checked using a diagnostic X-ray shadow free PTW ionization chamber model: SFD34060 coupled to an electrometer model: UNIDOS E, linear calibration curves were obtained for the OSL and TLD. Results. The average measured ESD using the OSL and the TLD were 66 and 70 lGy respectively. The OSL were found suitable to conduct ESD measurements during chest X-ray exam for the neonatal patient. The obtained patient dose measurement will serve as an indicator of quality and patient safety standard in diagnostic radiology services. Conclusion. The measured values are within internationally published data. The study serves as a benchmark to our clinical practice against international diagnostic reference levels (DRL) in pediatric radiology. https://doi.org/10.1016/j.ejmp.2018.06.337
[P005] How much of patient dose is unjustified in CT head and abdomen exams? Evangelia Papageorgiou a,*, Vassiliki Georgopoulou b, Spyros Papadopoulos b a Hippokratio General Hospital of Thessaloniki, Medical Physics, Thessaloniki, Greece b Hippokratio General Hospital of Thessaloniki, Radiology, Thessaloniki, Greece ⇑ Corresponding author.
Purpose. Justification of medical exposures, especially of the high dose CT exams, should be fully implemented. The purpose of this study was the investigation of the unjustified CT head and abdomen exams and the evaluation of patient doses in a tertiary Greek hospital. Methods. Two radiologists reviewed and evaluated the justification of 209 CT Head and 283 CT Abdomen referrals based on the American College of Radiation Appropriateness CriteriaÒ and medical expertise. Patient status (emergency or not) and diagnostic outcome (positive/negative) were recorded. Effective doses were calculated based on Dose-Length-Product indications. Results. Sixty (29%) of the Head examinations were considered unjustified and could have been replaced by MRI or not a radiologi-
cal examination was needed, referred mainly for minor head trauma and headache. Sixty-eight (24%) of the Abdomen examinations were considered unjustified and could have been replaced by MRI &/ US or other type of examination, referred mainly for malignancy screening and abdominal pain. Thirty-seven of the Head and 37 of the Abdomen unjustified exams had negative outcome. The odds of having negative outcome for the unjustified exams compared with the justified ones were twofold (p < 0.0001). More unjustified examinations were referred for the non-emergency patients (p < 0.0001). Collective dose was 10.1 manSv for the Head exams of which 1.7 manSv were unjustified and negative and 71.4 manSv for the Abdomen exams of which 9.4 manSv were unjustified and negative. Conclusions. The non-implementation of referral criteria by clinicians for CT Head and Abdomen exams leads to a nearly 14% of unnecessary patient doses. https://doi.org/10.1016/j.ejmp.2018.06.338
[P006] DRL’s in mammography: Results from 3 dose audits Ana Roda a,*, Inês Santos b, Ana Maria Lopes b, Idílio Filipe Gomes b, Maria do Carmo Lopes a a Instituto Português de Oncologia de Coimbra Francisco Gentil, Epe, Medical Physics Department, Coimbra, Portugal b Instituto Português de Oncologia de Coimbra Francisco Gentil, Epe, Radiology Department, Coimbra, Portugal ⇑ Corresponding author.
Purpose. We compare the results of 3 dose audits (2013, 2015 and 2017) for bilateral mammography screening exams performed in a full field digital mammography unit GE Senographe DS. We estimated the average entrance surface dose (ESD) for a sample of at least 50 standard breasts. The results were compared with the European DRL - ESD of the 3rd quartile of the dose survey. We estimated average absorbed dose to the glandular tissue within breast (AGD) for a wide range of breast thicknesses, and converted it into effective dose. Data was presented to the staff to induce a process of optimization as team effort. Methods. For each dose audit we selected a sample of more than 150 bilateral mammography screening exams. The percentage glandularity was determined using the qualitative method described by Byng (1994) and compared with Dance (2000) empirical formula. AGD was determined from measurements of the output and exposure data using appropriate conversion factors from IAEA (2007), Dance (2000), Dance (2009). Effective doses were determined using ICRP 103 breast tissue weighting factor 0.12. Results. Results (2013): ESD = 5.8 mGy for cranio caudal (CC) and ESD = 6.1 mGy for medio lateral oblique (MLO) projections. These results are considerably below the European DRL’s (10 mGy). E ranged from: E = 0.28 mSv for small breasts (34.5 ± 4.5 mm) to E = 0.69 mSv for very large breasts (84.5 ± 4.5 mm) with larger compressed breast thickness associated with a higher AGD (E); Results (2015): around 30% increase in DRLs: ESD = 8.6 mGy CC and ESD = 8.7 mGy MLO; E ranged from E = 0.38 mSv for small breasts (34.5 ± 4.5 mm) to E = 0.75 mSv for very large breasts (84.5 ± 4.5 mm); Results (2017): within 5% of 2013. Conclusions. The 30% increase in the dose results in 2015 resulted from the increased use of Contrast Enhanced Automatic Optimization of Parameters (AOP CNR) mode. This action was investigated and corrected. Dose audits are important part of a quality assurance program. https://doi.org/10.1016/j.ejmp.2018.06.339