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Estimation of typical patient doses in digital radiology department
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Abstracts / Physica Medica 30 (2014) e75ee121
Aim: The aim of this study is to estimate the impact of rhTSH on total body residence time, ttb , after 131I treatment. Materials and methods: 48 DTC patients, who were referred to our centre for their first ablation and/or follow up dose since 2012, were enrolled in this study and divided in 2 groups. Group A included 19 pts received 131I therapy, once with rhTSH stimulus and more than once after thyroid hormone withdrawal. Group B included 29 pts treated only once with rhTSH stimulus. Ablation and follow up dosage were 100 and 200 mCi respectively. Total body dose rate measurements, during the seven days after administration, performed by Inovision 451P survey meter were recorded and converted to activity. Total body residence time was calculated by data analysis software Origin8, whereas statistical analysis of the results was performed by SPSS 13.0. Results: Applying paired samples statistics of Group A patients, mean whole body residence time, ttb, was 28.2±10.6h when treated with rhTSH stimulus and 33.8±11h in the case of no rhTSH stimulus. There was no statistically significant difference between the derived values. In addition, statistical analysis of all therapies from groups A and B, with and without rhTSH stimulus, ended up to the same result. Conclusions: These data suggest that, during 131I treatment, whole body residence time of 131I does not alter significantly, with the method of patient preparation (rhTSH stimulus vs thyroid hormone withdrawal). It will be of great importance to investigate rhTSH effect on blood residence time of 131I, tblood , since they both have a great impact on blood dosimetry according to the guidelines of EANM Dosimetry Committee. IMPACT OF CENTRALIZED RADIO PHARMACY SERVICES AMONG FOUR HOSPITALS IN THE 4TH REGIONAL HEALTH AUTHORITY OF MACEDONIA AND THRACE
The purpose of this work is to estimate patient doses from the most commonly performed procedures in a digital radiology department, to compare them with the national DRLs established in the country and to look for a potential of optimization. Materials and methods: The X-ray systems in the imaging department are: digital radiography (DR) system, C-arm fluoroscopy system, 16 slices computed tomography (CT) system, and DR mammography system, all of them manufactured by GE. The most common procedures are chest X-ray performed with the DR system, hysterosalpingography with the fluoroscopy system, and abdomen, chest, head and lumbar spine scans on the CT. Data necessary for dose estimations were extracted from the DICOM header of the patient examination files. Tube output measurements were made on the DR system and kerma area product (KAP) from the DICOM header was compared with the calculated data from the measurements. Entrance surface air kerma (ESAK) rate was measured on the C-arm for all modes. Computed tomography kerma index (CTKI) in phantom was measured and compared with data from the CT display. Tube output and half value layer were measured on the mammography system and incident air kerma and mean glandular dose were calculated for phantom and patients. Results: Not very good agreement was found between the measured and extracted data for DR (up to 28 % for some KAP values) and bigger difference for CTKI (16 % for abdomen and 37 % for head examinations). Estimated local typical patient doses were found to be lower than the national DRLs. Discussion: The current national DRLs were established 5 years ago and a lot of new digital systems were installed afterwards. They provide big potential for reduction of patient doses compared to old analogue systems. New DRLs are planned to be established during next two years and probably lower values will be set.
Maria Kotzassarlidou. Medical Physics Dept., “Theagenion” Cancer Hospital, Thessaloniki, Greece The aim of this study is to examine and evaluate a realistic case of establishing a shared radiopharmacy program for the Nuclear Medicine Departments of four hospitals in the 4th Regional Health Authority of Macedonia and Thrace (4thRHA), located in the same area of Thessaloniki. The hospitals involved in this study are: University General Hospital of Thessaloniki “AHEPA”, General Hospital “IPPOKRATIO”, First General Hospital “ST.PAUL’S”, Cancer Hospital “THEAGENIO”. Data were taken from the international and greek literature, the above mentioned hospitals and 4thRHA. Principles of the study were adopted by the Operational Restructuring Plan for Greek Hospitals, prepared by the National University of Athens , for the Ministry of Health. Current situation of the above mentioned Nuclear Medicine Departments was presented, regarding equipment, personnel, type and number of tests, budget for consumption of radiopharmaceuticals. Cost and manpower savings were estimated for the case of establishing centralized radiopharmacy services among these departments. According to the results, a shared radiopharmacy program is expected to cause a reduction in annual spending of 92900 V by all the participating hospitals. Patients’ waiting time may be reduced whereas patient welfare may be increased. In addition, more efficient human resource management can be achieved, improving and upgrading the practice of nuclear medicine and patient care in the participating hospitals.
ESTIMATION OF TYPICAL PATIENT DOSES IN DIGITAL RADIOLOGY DEPARTMENT S. Avramova-Cholakova a,b, N. Nenova-Balatsenko b. aNational Centre of Radiobiology and Radiation Protection, Bulgaria; bHospital for Women’s Health “Nadezhda”, Bulgaria Background: Bulgarian legislation introduced in 2005 requirement for elaboration of Diagnostic Reference Levels (DRL) and estimation of local typical doses in every department. There is still little experience in the country with the estimation and use of typical doses, which is not routinely performed yet.
BEAM SPECIFIC CALCULATION CHECKS FOR TREATMENT PLANNING SYSTEM COMMISSIONING Patatoukas George, Dilvoi Maria, Platoni Kalliopi, Papadogiannis Panagiotis, Chalkia Marina, Efstathopoulos Efstathios. Medical Physics Unit, 2nd Department of Radiology, Medical School, University of Athens, Greece Background: Commissioning is one of the most important parts of the entire QA programme for both the TPS and the planning process. Beam specific calculation checks can be used to detect the differences between measured and calculated doses. These checks relate to single beam irradiations of water phantom under the conditions close to those used for the clinical commissioning tests and are designed in such manner that the user should be able to compare the results for selected points with the calculated dose values. We present a (portion of the) series of dose-related measurements that took place in our department in order to prepare the Varian AAA dose calculation algorithm for use in our department’s everyday clinical practice. Materials and methods: The medical physics team of our radiotherapy department followed all procedures described by AAPM TG 51, IAEA report 430 as well as IAEA TEC-DOC-1583 for the AAA beam data commissioning following a software update that took place in the department. We compared point doses in a number of fields and depths for two Varian Linear Accelerators (LINACs).The format of the beam specific calculation checks includes the check of output factors, field width and penumbra size for a range of field sizes for open and wedged fields used in clinical commissioning and also a check of the doses in different parts of the water phantom for open and wedged beams. Results: Dose calculation checks were performed for three open fields (4cm x 4cm, 10cm x 10cm, 25cm x 25cm) and for one wedged (10cm x 10cm) at four measurement depths (dmax, 5cm, 10cm and 20cm). Dose to points on the central axis and off-axis point(s) was measured. Dose calculation checks for high-energy x-ray beams (6 and 15MV) were expressed in dose units (cGy). The difference between these calculated data and the corresponding measured data can be calculated
Abstracts / Physica Medica 30 (2014) e75ee121
Aim: The aim of this study is to estimate the impact of rhTSH on total body residence time, ttb , after 131I treatment. Materials and methods: 48 DTC patients, who were referred to our centre for their first ablation and/or follow up dose since 2012, were enrolled in this study and divided in 2 groups. Group A included 19 pts received 131I therapy, once with rhTSH stimulus and more than once after thyroid hormone withdrawal. Group B included 29 pts treated only once with rhTSH stimulus. Ablation and follow up dosage were 100 and 200 mCi respectively. Total body dose rate measurements, during the seven days after administration, performed by Inovision 451P survey meter were recorded and converted to activity. Total body residence time was calculated by data analysis software Origin8, whereas statistical analysis of the results was performed by SPSS 13.0. Results: Applying paired samples statistics of Group A patients, mean whole body residence time, ttb, was 28.2±10.6h when treated with rhTSH stimulus and 33.8±11h in the case of no rhTSH stimulus. There was no statistically significant difference between the derived values. In addition, statistical analysis of all therapies from groups A and B, with and without rhTSH stimulus, ended up to the same result. Conclusions: These data suggest that, during 131I treatment, whole body residence time of 131I does not alter significantly, with the method of patient preparation (rhTSH stimulus vs thyroid hormone withdrawal). It will be of great importance to investigate rhTSH effect on blood residence time of 131I, tblood , since they both have a great impact on blood dosimetry according to the guidelines of EANM Dosimetry Committee. IMPACT OF CENTRALIZED RADIO PHARMACY SERVICES AMONG FOUR HOSPITALS IN THE 4TH REGIONAL HEALTH AUTHORITY OF MACEDONIA AND THRACE
The purpose of this work is to estimate patient doses from the most commonly performed procedures in a digital radiology department, to compare them with the national DRLs established in the country and to look for a potential of optimization. Materials and methods: The X-ray systems in the imaging department are: digital radiography (DR) system, C-arm fluoroscopy system, 16 slices computed tomography (CT) system, and DR mammography system, all of them manufactured by GE. The most common procedures are chest X-ray performed with the DR system, hysterosalpingography with the fluoroscopy system, and abdomen, chest, head and lumbar spine scans on the CT. Data necessary for dose estimations were extracted from the DICOM header of the patient examination files. Tube output measurements were made on the DR system and kerma area product (KAP) from the DICOM header was compared with the calculated data from the measurements. Entrance surface air kerma (ESAK) rate was measured on the C-arm for all modes. Computed tomography kerma index (CTKI) in phantom was measured and compared with data from the CT display. Tube output and half value layer were measured on the mammography system and incident air kerma and mean glandular dose were calculated for phantom and patients. Results: Not very good agreement was found between the measured and extracted data for DR (up to 28 % for some KAP values) and bigger difference for CTKI (16 % for abdomen and 37 % for head examinations). Estimated local typical patient doses were found to be lower than the national DRLs. Discussion: The current national DRLs were established 5 years ago and a lot of new digital systems were installed afterwards. They provide big potential for reduction of patient doses compared to old analogue systems. New DRLs are planned to be established during next two years and probably lower values will be set.
Maria Kotzassarlidou. Medical Physics Dept., “Theagenion” Cancer Hospital, Thessaloniki, Greece The aim of this study is to examine and evaluate a realistic case of establishing a shared radiopharmacy program for the Nuclear Medicine Departments of four hospitals in the 4th Regional Health Authority of Macedonia and Thrace (4thRHA), located in the same area of Thessaloniki. The hospitals involved in this study are: University General Hospital of Thessaloniki “AHEPA”, General Hospital “IPPOKRATIO”, First General Hospital “ST.PAUL’S”, Cancer Hospital “THEAGENIO”. Data were taken from the international and greek literature, the above mentioned hospitals and 4thRHA. Principles of the study were adopted by the Operational Restructuring Plan for Greek Hospitals, prepared by the National University of Athens , for the Ministry of Health. Current situation of the above mentioned Nuclear Medicine Departments was presented, regarding equipment, personnel, type and number of tests, budget for consumption of radiopharmaceuticals. Cost and manpower savings were estimated for the case of establishing centralized radiopharmacy services among these departments. According to the results, a shared radiopharmacy program is expected to cause a reduction in annual spending of 92900 V by all the participating hospitals. Patients’ waiting time may be reduced whereas patient welfare may be increased. In addition, more efficient human resource management can be achieved, improving and upgrading the practice of nuclear medicine and patient care in the participating hospitals.
ESTIMATION OF TYPICAL PATIENT DOSES IN DIGITAL RADIOLOGY DEPARTMENT S. Avramova-Cholakova a,b, N. Nenova-Balatsenko b. aNational Centre of Radiobiology and Radiation Protection, Bulgaria; bHospital for Women’s Health “Nadezhda”, Bulgaria Background: Bulgarian legislation introduced in 2005 requirement for elaboration of Diagnostic Reference Levels (DRL) and estimation of local typical doses in every department. There is still little experience in the country with the estimation and use of typical doses, which is not routinely performed yet.
BEAM SPECIFIC CALCULATION CHECKS FOR TREATMENT PLANNING SYSTEM COMMISSIONING Patatoukas George, Dilvoi Maria, Platoni Kalliopi, Papadogiannis Panagiotis, Chalkia Marina, Efstathopoulos Efstathios. Medical Physics Unit, 2nd Department of Radiology, Medical School, University of Athens, Greece Background: Commissioning is one of the most important parts of the entire QA programme for both the TPS and the planning process. Beam specific calculation checks can be used to detect the differences between measured and calculated doses. These checks relate to single beam irradiations of water phantom under the conditions close to those used for the clinical commissioning tests and are designed in such manner that the user should be able to compare the results for selected points with the calculated dose values. We present a (portion of the) series of dose-related measurements that took place in our department in order to prepare the Varian AAA dose calculation algorithm for use in our department’s everyday clinical practice. Materials and methods: The medical physics team of our radiotherapy department followed all procedures described by AAPM TG 51, IAEA report 430 as well as IAEA TEC-DOC-1583 for the AAA beam data commissioning following a software update that took place in the department. We compared point doses in a number of fields and depths for two Varian Linear Accelerators (LINACs).The format of the beam specific calculation checks includes the check of output factors, field width and penumbra size for a range of field sizes for open and wedged fields used in clinical commissioning and also a check of the doses in different parts of the water phantom for open and wedged beams. Results: Dose calculation checks were performed for three open fields (4cm x 4cm, 10cm x 10cm, 25cm x 25cm) and for one wedged (10cm x 10cm) at four measurement depths (dmax, 5cm, 10cm and 20cm). Dose to points on the central axis and off-axis point(s) was measured. Dose calculation checks for high-energy x-ray beams (6 and 15MV) were expressed in dose units (cGy). The difference between these calculated data and the corresponding measured data can be calculated