- Email: [email protected]
Pre-Radiotherapy (RT) treatment planning factors to take into account in oncologic patients with Inflammatory Bowel Diseases (IBD)
Abstracts / Physica Medica 30 (2014) e75ee121
Background: Arterial blood flow characteristics can be studied nonedinvasively using Magnetic Resonance Imaging. Magnetic Resonance angiography provides real-time velocity information. This functional information is of paramount importance in the study of arterial blood flow characteristics and can lead to the quantification of individual hemodynamic-related parameters in any patient; it can also assist in the development of diagnostic tools to quantify artery disease and it can contribute to the design of devices that mimic blood flow either for educational purposes or for developing tools that alter blood flow. Materials and methods: To simulate blood circulation in stenotic arteries, a positive displacement pump driven by an electrocardiogram (ECG) generator was used. Water was considered as the flow medium of choice. Three different glass tubes, each exhibiting a stenotic geometry were studied. The percentage of the stenosis was unknown. The glass stenotic tubes were placed between two gelatin layers to mimic tissue-equivalent material and to enhance MRI signal acquisition. Imaging was performed with a Philips Intera 1.5T MRI system using phase contrast sequences. Results were compared to CT image-based stenosis quantification. Results: Velocity values were acquired and recorded pre- and poststenotically for each glass tube. Stenosis percentage quantification was performed using the MRI-velocity information. In addition, Signal To Noise Ratio (SNR) calculation was performed around the stenotic vicinity (preand post-) and their ratio was noted and related to stenosis percentage. Furthermore, velocity profiles were acquired, studied and compared to the theoretical parabolic profile. Finally the MRI flow-based calculated values for each of the stenosis percentage were compared to those extracted using CT imaging anatomy. Discussion: Higher flow velocity values were observed post-stenotically. The length of the induced jet and the consequent signal loss were related to the stenosis percentage. Turbulent flow and dispersion of velocity values is an important factor of signal lose in the stenotic vicinity. CT based and MR based stenosis quantification exhibited differences. Further steps need to be done in MR imaging to fully appreciate and quantify each factor that influences blood flow.
S.E.Y.Y.P INSPECTIONS RELATED WITH RADIOLOGY DEPARTMENTSLABORATORIES FOR THE IMPROVEMENT OF PUBLIC HEALTH IN GREECE E. Kounadi, I. Manousopoulou, N. Kallitsantsis, M. Adamopoulou, V. Panagopoulos, H. Merentitis, P. Sakellariou, M. Rekkas, S. Sampatakakis. Ministry of Health in Greece, SEYYP, Athens Greece Background: In Greece, under current legislation the Radiology Departments-Labs (DL) must be equipped with specific ionizing and nonionizing radiation diagnostic systems. Special operating license required for Radiology DL operation which must be renewed every five years. Also quality control program for each system is mandatory. The purpose of this work is to present the results of SEYYP inspections related with Radiology DL, i.e. the problems identified, and proposals that can eliminate these problems. Materials and methods: The SEYYP where its services aiming to improve the Public Health, during the years 2012-2014, have been carried out inspections related with public and private Radiology DL in urban areas and in the countryside. In this inspection procedure was checked and implicated, not only the Radiology DL, but also the related public health services. Inspection subjects, was the licensing of DL and the proper operation of them. Also issues related to magnetic tomographs (MRI) licensing and statistical data related to the computed tomography (CT) examinations, in the country, was explored. Results: At Radiology DL, where problems with their licensing, was found after the inspection forced to comply with the current legislation. In some of them monetary penalties was imposed or they were forced to close down for some time. Deficiencies in current legislation for the MRIs licensing was identified and proposals for the improvement was formulated. In the conduction of the CT exams, great variation, in the CT exams number per 1,000 inhabitants, between public hospitals from different Local Regions, was found. Also great variation at the number of exams per CT system, for the year 2013, in Public Hospitals in the country was identified.
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Discussion: The recommendations that were performed at checked and implicated public services and Radiation DL, were aiming to improve the public health in the country. Thus proposals for a more efficient use of manpower and medical instrumentation in public Hospitals, taking into account the economic situation of the country, was performed. Furthermore proposals to reduce the induced demand of the CT exams in the country were made. EVALUATION OF THE ACCURACY OF THE ELECTRON TRANSPORT ALGORITHMS OF THE MCNP6 AND EGSNRC MONTE CARLO CODES USING THE FANO THEOREM E. Zoros, E. Pappas, E. Pantelis. Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 11527 Athens, Greece Background: Monte Carlo (MC) codes are commonly used for simulating ion chamber response in photon or electron beams. Besides cross section libraries, accurate modelling of the ion chamber and beam quality, the accuracy of the obtained results depends also on the electron transport algorithm (ETA) parameters used by the MC codes. In this study, the accuracy of the ETA of the recently released MCNP6 as well as of the EGSnrc MC codes is evaluated using the Fano theorem. Methods: MCNP and EGSnrc simulations were performed for a cylindrical infinite graphite slab phantom containing a cavity delimited by two parallel planes. The cavity was filled with ‘gas’ of the same composition as graphite but with mass density of a thousand-fold smaller. Identical cross sections (including the density effect) were used for both the cavity walls and the gas. Electrons with initial kinetic energies ranging from 0.05MeV to 10MeV were generated in the wall and in the gas with a uniform intensity per unit mass. The initial emission direction was either perpendicular or parallel to the gasewall interface motivated by the design of pancake- and thimble-type chambers. The degree of violation of the Fano theorem was quantified for the default parameters of the EGSnrc and as a function of the ESTEP parameter (determining the number of sub-steps per energy step) for the MCNP codes, respectively. For the MCNP simulations the new energy indexing method was used. The effect of the ESTEP value on simulation efficiency was also studied. Results: Results showed that EGSnrc verifies Fano theorem within 0.1% for the studied electron energies. Corresponding MCNP results showed that the default ESTEP value of 3 should be used only for electron kinetic energies of 0.05MeV. As energy increases a greater ESTEP parameter should be used, taking a value of 30 for 10MeV electron energy, to obtain dosimetry results with 0.1% accuracy. Increasing ESTEP up to 30 downgrades time efficiency, by a factor of 4 for 1MeV electron energy. Discussion: This work is intended to help users adopt the optimal parameters of the MCNP and EGSnrc MC codes that guarantee high-accuracy dosimetry calculations. PRE-RADIOTHERAPY (RT) TREATMENT PLANNING FACTORS TO TAKE INTO ACCOUNT IN ONCOLOGIC PATIENTS WITH INFLAMMATORY BOWEL DISEASES (IBD) M. Tolia a, A. Zygogianni a, G. Kyrgias b, K. Theodorou b, C. Kappas b, J. Kouvaris a, V. Kouloulias a. a 1st Department of Radiology, Radiation Oncology Unit, Aretaieion University Hospital, Vassilissis Sofias 76, 115 28, Medical School of Athens, Greece; b Radiotherapy Department, Larissa University Hospital, Medical School of Thessaly, Greece Background: IBD represents a chronic intestinal inflammation in the absence of an infectious or dietary cause. IBD can produce many similar clinical characteristics as RT toxicity and has been considered a relative contraindication for the delivery of RT. There is a relative scarcity of data concerning the safety of irradiation for oncologic patients with an IBD history. We evaluated the optimal treatment factors in order to reduce the risk of RT bowel toxicity in oncologic IBD patients. Materials and methods: A review of all published reports was performed by Medline. Results: Modern techniques such as image-guided tomotherapy or volumetric-modulated arc therapy may possibly permit the administration of higher doses with less bowel toxicity. Use of IORT and brachytherapy (vaginal implant, perineal proton boost) in combination of
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Abstracts / Physica Medica 30 (2014) e75ee121
photon radiotherapy in order to deliver supplemental irradiation. Brachytherapy in early-stage prostate cancer should be considered. Special positioning (prone or decubitus) and fully distended bladder to minimize bowel irradiation. Surgical omentoplasty, dexon, vicryl mesh and tissue expanders to mobilize the bowel away from irradiated area. Surgical clips placement are useful for precise tumor localization and delineation of tumor bed. Delivery of only a fraction, not higher than 1.8e2 Gy daily. Reduction of total dose and eventually employment of scheduled rest periods during RT. Hormonal therapy could shrink the prostatic gland (downsizing) in prostate cancer patients and thus reduce the radiation field size. Steroid-induced femoral head osteonecrosis represents an aseptic and ischemic disease developing after chronic administration of steroids in IBD patients. Keep doses within femoral head tolerance. Care must also be taken to age associated osteoporosis in geriatric patients. Discussion: A special attention should be given to RT dose and technique, in order to minimize post-RT complications. NATIONAL PATIENT DOSE SURVEY IN DENTAL CBCT AND ELABORATION OF NATIONAL DRLS D. Petrov, J. Vassileva. National centre of radiobiology and radiation protection, Sofia, Bulgaria Background: The aim of this study is to present results from the national patient dose survey in cone beam CT (CBCT) used in dental practice, and to elaborate national diagnostic reference levels (DRL). Materials and methods: Patient doses were measured with calibrated kerma-area product (KAP) dosemeter Diamentor E2 (PTW Freiburg), installed on the tube housing exit. Patient head was simulated with a standart CT head phantom. The size of the radiation field was measured with Gafchromic film placed on the imaging detector. Organ doses and effective dose E were calculated with PCXMC v.2.0 (STUK) by Monte Carlo simulation. Pilot measurements were performed on three CBCT: one NewTomVG (QR-Italy)and two ILUMAeImtec 3M (USA). Results: CBCT dose varied substantially depending on the device, field of view (FOV), and selected technique factors. Up to 3 fold differences were found between KAP for adult patient, with lower values for the system NewTomVG, working with tube current modulation. Discussion: Complete set of ongoing measurements and analysis will be presented, as well as findings and conclusions. COMPARISON OF 111IN-OCTREOSCAN AND 99MTC-TEKTROTYDE IN TECHNICAL MATERS [RADIOLABELING, QUALITY CONTROL, INJECTED DOSES AND PATIENT RADIATION EXPOSURE] M. Papachristou, І. Xirafi, I. Datseris. Department of Nuclear Medicine e PET/CT General Hospital of Athens “Evaggelismos” Introduction: The imaging of positive SSTR's tumours with radiolabeled analogues of somatostatine has a broad use in oncology. The radiopharmaceutical of choice was 111In-DTPA-D-Phe-Octreotide. The use of 111In is facing some problems because it depends in cyclotron production which leads to restricted availability and very high cost. So to overcome these problems the use of 99mTc was selected as “easy- toget” radionuclide with low cost. The 99mTc-EDDA/HYNIC-Tyr3-Octreotide can image the tumours with SSTRs. We report a comparison between the 111In-Octreoscan and 99mTc-Tektrotyde in radiolabeling, quality control, injected doses and patient radiation exposure. Methods: The radiolabeling procedure of both radiopharmaceuticals were carried out according to the SPC of the products and the European Pharmacopeia. After the labelling, both drugs undergo quality control which includes pH measurements, visual control and instant thin layer chromatography (TLC), in order to be released. One vial 111In-Octreoscan is used for one single patient and one vial of 99m Tc-Tektrotyde is used for two patients. The dose of the 111In is ~5 mCi and the dose of 99mTc is ~ 20 mCi in accordance with our Department protocols. Results: To label 111In-Octreoscan takes 30 min and to label 99mTc-Tektrotyde takes almost 50 min. The quality control of 111In needs only one TLC
system (~ 20 min) where for the 99mTc needs two TLC systems (~ 40 min). The patient’s injected with111In have higher radiation exposure than the patients injected with 99mTc. The imaging protocol of 111In is a 2-day, one day longer than 99mTc (1-day protocol). Conclusions: 111In- Octreoscan is a well standardized and well know radiopharmaceutical with easy labelling procedure and quality control. Its cons are the 2-days protocol, the higher radiation exposure, the higher cost and the short availability. 99m Tc- Tektrotyde is a new radiopharmaceutical which isn’t well defined. Its radiolabeling procedure and quality control are long. 99mTc-Tektrotyde pros are the 1-day protocol, the lower radiation exposure, the lower cost for two patients and it's broad availability. Both radiopharmaceuticals have advantages and disadvantages. The choice depends on the Nuclear Medicine Department’s resources, protocols and qualification standards.
BLOODLESS MEASUREMENT OF HEMATOCRIT M. Adamopoulou a, G. Fountos b, E. Kounadi a, M. Rekkas a. a Ministry of Health in Greece, SEYYP, Athens, Greece; b Department of Biomedical Engineering, TEI of Athens, Greece Background: The direct estimation of the hematocrit at surgery without blood sampling procedures and laboratory analyzes, could yield significant time savings for the clinician, especially when managing emergencies. The purpose of this study is the construction of a biotechnology device, in order to determine the hematocrit value, in a bloodless non invasive method, that can be used for an immediate diagnosis. Materials and methods: Using technology similar to that of an “oxymeter”, we are in the process of manufacturing a portable device, which in contact with a large vase (jugular, femoral or brachial artery etc), will be able to count the number of red blood cells per cubic millimeter. The red blood cells are identified by their concave surface, separating them from the remaining blood cells (white blood cells , platelets, etc), where light scattering occurs in a different way. Results: After the completion of the prototype which called «Hemo-detector», measurements of hematocrit will be performed using this device to patients. The hematocrit values measured will be compared with them upon laboratory tests (blood draw) to assess the reliability of this novel non invasive method. Discussion: The immediate and bloodless measurement of hematocrit is an important help for the clinician where he will be able to evaluate a significant number of diseases. Also, pain and stress for the patient can be avoided. Furthermore, since this will be a low cost method resources for the patient as well as social health funds can be saved. THE ROLE OF DOSIMETRIC CALCULATIONS IN OPTIMIZING PEPTIDE RECEPTOR RADIONUCLIDE THERAPY BY [177LU-DOTA0, TYR3] OCTREOTATE Irini Baka a, Maria Argyrou a, Marina Michalitsi a, Alexia Valassi a, Agapi Ploussi a, Maria Lyra a, b. a Radiation Physics Unit, 1st Department of Radiology, Aretaieion hospital, University of Athens, Greece; b Nuclear Medicine Section, 1st Department of Radiology, Aretaieion hospital, University of Athens, Greece Aim: Response and toxicity prediction is essential to the implementation of Peptide Receptor Radionuclide Therapy (PRRT) for neuroendocrine tumors. Radiolabelled somatostatin analogue [177Lu-DOTA0, Tyr3] octreotate stands as a promising therapy tool. Specific dosimetry is a crucial factor in patient treatment planning. Dosimetric techniques implemented in our Institution are presented. Methods: In our Institution, neuroendocrine tumor treatment, by radiopeptide infusion via intrahepatic arterial catheterization, is a well established technique. Kidney protective agents are also included in our protocol. The individualized patient dosimetry calculations were based on planar and SPECT scintigraphy images. Counts were
Background: Arterial blood flow characteristics can be studied nonedinvasively using Magnetic Resonance Imaging. Magnetic Resonance angiography provides real-time velocity information. This functional information is of paramount importance in the study of arterial blood flow characteristics and can lead to the quantification of individual hemodynamic-related parameters in any patient; it can also assist in the development of diagnostic tools to quantify artery disease and it can contribute to the design of devices that mimic blood flow either for educational purposes or for developing tools that alter blood flow. Materials and methods: To simulate blood circulation in stenotic arteries, a positive displacement pump driven by an electrocardiogram (ECG) generator was used. Water was considered as the flow medium of choice. Three different glass tubes, each exhibiting a stenotic geometry were studied. The percentage of the stenosis was unknown. The glass stenotic tubes were placed between two gelatin layers to mimic tissue-equivalent material and to enhance MRI signal acquisition. Imaging was performed with a Philips Intera 1.5T MRI system using phase contrast sequences. Results were compared to CT image-based stenosis quantification. Results: Velocity values were acquired and recorded pre- and poststenotically for each glass tube. Stenosis percentage quantification was performed using the MRI-velocity information. In addition, Signal To Noise Ratio (SNR) calculation was performed around the stenotic vicinity (preand post-) and their ratio was noted and related to stenosis percentage. Furthermore, velocity profiles were acquired, studied and compared to the theoretical parabolic profile. Finally the MRI flow-based calculated values for each of the stenosis percentage were compared to those extracted using CT imaging anatomy. Discussion: Higher flow velocity values were observed post-stenotically. The length of the induced jet and the consequent signal loss were related to the stenosis percentage. Turbulent flow and dispersion of velocity values is an important factor of signal lose in the stenotic vicinity. CT based and MR based stenosis quantification exhibited differences. Further steps need to be done in MR imaging to fully appreciate and quantify each factor that influences blood flow.
S.E.Y.Y.P INSPECTIONS RELATED WITH RADIOLOGY DEPARTMENTSLABORATORIES FOR THE IMPROVEMENT OF PUBLIC HEALTH IN GREECE E. Kounadi, I. Manousopoulou, N. Kallitsantsis, M. Adamopoulou, V. Panagopoulos, H. Merentitis, P. Sakellariou, M. Rekkas, S. Sampatakakis. Ministry of Health in Greece, SEYYP, Athens Greece Background: In Greece, under current legislation the Radiology Departments-Labs (DL) must be equipped with specific ionizing and nonionizing radiation diagnostic systems. Special operating license required for Radiology DL operation which must be renewed every five years. Also quality control program for each system is mandatory. The purpose of this work is to present the results of SEYYP inspections related with Radiology DL, i.e. the problems identified, and proposals that can eliminate these problems. Materials and methods: The SEYYP where its services aiming to improve the Public Health, during the years 2012-2014, have been carried out inspections related with public and private Radiology DL in urban areas and in the countryside. In this inspection procedure was checked and implicated, not only the Radiology DL, but also the related public health services. Inspection subjects, was the licensing of DL and the proper operation of them. Also issues related to magnetic tomographs (MRI) licensing and statistical data related to the computed tomography (CT) examinations, in the country, was explored. Results: At Radiology DL, where problems with their licensing, was found after the inspection forced to comply with the current legislation. In some of them monetary penalties was imposed or they were forced to close down for some time. Deficiencies in current legislation for the MRIs licensing was identified and proposals for the improvement was formulated. In the conduction of the CT exams, great variation, in the CT exams number per 1,000 inhabitants, between public hospitals from different Local Regions, was found. Also great variation at the number of exams per CT system, for the year 2013, in Public Hospitals in the country was identified.
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Discussion: The recommendations that were performed at checked and implicated public services and Radiation DL, were aiming to improve the public health in the country. Thus proposals for a more efficient use of manpower and medical instrumentation in public Hospitals, taking into account the economic situation of the country, was performed. Furthermore proposals to reduce the induced demand of the CT exams in the country were made. EVALUATION OF THE ACCURACY OF THE ELECTRON TRANSPORT ALGORITHMS OF THE MCNP6 AND EGSNRC MONTE CARLO CODES USING THE FANO THEOREM E. Zoros, E. Pappas, E. Pantelis. Medical Physics Laboratory, Medical School, University of Athens, 75 Mikras Asias, 11527 Athens, Greece Background: Monte Carlo (MC) codes are commonly used for simulating ion chamber response in photon or electron beams. Besides cross section libraries, accurate modelling of the ion chamber and beam quality, the accuracy of the obtained results depends also on the electron transport algorithm (ETA) parameters used by the MC codes. In this study, the accuracy of the ETA of the recently released MCNP6 as well as of the EGSnrc MC codes is evaluated using the Fano theorem. Methods: MCNP and EGSnrc simulations were performed for a cylindrical infinite graphite slab phantom containing a cavity delimited by two parallel planes. The cavity was filled with ‘gas’ of the same composition as graphite but with mass density of a thousand-fold smaller. Identical cross sections (including the density effect) were used for both the cavity walls and the gas. Electrons with initial kinetic energies ranging from 0.05MeV to 10MeV were generated in the wall and in the gas with a uniform intensity per unit mass. The initial emission direction was either perpendicular or parallel to the gasewall interface motivated by the design of pancake- and thimble-type chambers. The degree of violation of the Fano theorem was quantified for the default parameters of the EGSnrc and as a function of the ESTEP parameter (determining the number of sub-steps per energy step) for the MCNP codes, respectively. For the MCNP simulations the new energy indexing method was used. The effect of the ESTEP value on simulation efficiency was also studied. Results: Results showed that EGSnrc verifies Fano theorem within 0.1% for the studied electron energies. Corresponding MCNP results showed that the default ESTEP value of 3 should be used only for electron kinetic energies of 0.05MeV. As energy increases a greater ESTEP parameter should be used, taking a value of 30 for 10MeV electron energy, to obtain dosimetry results with 0.1% accuracy. Increasing ESTEP up to 30 downgrades time efficiency, by a factor of 4 for 1MeV electron energy. Discussion: This work is intended to help users adopt the optimal parameters of the MCNP and EGSnrc MC codes that guarantee high-accuracy dosimetry calculations. PRE-RADIOTHERAPY (RT) TREATMENT PLANNING FACTORS TO TAKE INTO ACCOUNT IN ONCOLOGIC PATIENTS WITH INFLAMMATORY BOWEL DISEASES (IBD) M. Tolia a, A. Zygogianni a, G. Kyrgias b, K. Theodorou b, C. Kappas b, J. Kouvaris a, V. Kouloulias a. a 1st Department of Radiology, Radiation Oncology Unit, Aretaieion University Hospital, Vassilissis Sofias 76, 115 28, Medical School of Athens, Greece; b Radiotherapy Department, Larissa University Hospital, Medical School of Thessaly, Greece Background: IBD represents a chronic intestinal inflammation in the absence of an infectious or dietary cause. IBD can produce many similar clinical characteristics as RT toxicity and has been considered a relative contraindication for the delivery of RT. There is a relative scarcity of data concerning the safety of irradiation for oncologic patients with an IBD history. We evaluated the optimal treatment factors in order to reduce the risk of RT bowel toxicity in oncologic IBD patients. Materials and methods: A review of all published reports was performed by Medline. Results: Modern techniques such as image-guided tomotherapy or volumetric-modulated arc therapy may possibly permit the administration of higher doses with less bowel toxicity. Use of IORT and brachytherapy (vaginal implant, perineal proton boost) in combination of
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Abstracts / Physica Medica 30 (2014) e75ee121
photon radiotherapy in order to deliver supplemental irradiation. Brachytherapy in early-stage prostate cancer should be considered. Special positioning (prone or decubitus) and fully distended bladder to minimize bowel irradiation. Surgical omentoplasty, dexon, vicryl mesh and tissue expanders to mobilize the bowel away from irradiated area. Surgical clips placement are useful for precise tumor localization and delineation of tumor bed. Delivery of only a fraction, not higher than 1.8e2 Gy daily. Reduction of total dose and eventually employment of scheduled rest periods during RT. Hormonal therapy could shrink the prostatic gland (downsizing) in prostate cancer patients and thus reduce the radiation field size. Steroid-induced femoral head osteonecrosis represents an aseptic and ischemic disease developing after chronic administration of steroids in IBD patients. Keep doses within femoral head tolerance. Care must also be taken to age associated osteoporosis in geriatric patients. Discussion: A special attention should be given to RT dose and technique, in order to minimize post-RT complications. NATIONAL PATIENT DOSE SURVEY IN DENTAL CBCT AND ELABORATION OF NATIONAL DRLS D. Petrov, J. Vassileva. National centre of radiobiology and radiation protection, Sofia, Bulgaria Background: The aim of this study is to present results from the national patient dose survey in cone beam CT (CBCT) used in dental practice, and to elaborate national diagnostic reference levels (DRL). Materials and methods: Patient doses were measured with calibrated kerma-area product (KAP) dosemeter Diamentor E2 (PTW Freiburg), installed on the tube housing exit. Patient head was simulated with a standart CT head phantom. The size of the radiation field was measured with Gafchromic film placed on the imaging detector. Organ doses and effective dose E were calculated with PCXMC v.2.0 (STUK) by Monte Carlo simulation. Pilot measurements were performed on three CBCT: one NewTomVG (QR-Italy)and two ILUMAeImtec 3M (USA). Results: CBCT dose varied substantially depending on the device, field of view (FOV), and selected technique factors. Up to 3 fold differences were found between KAP for adult patient, with lower values for the system NewTomVG, working with tube current modulation. Discussion: Complete set of ongoing measurements and analysis will be presented, as well as findings and conclusions. COMPARISON OF 111IN-OCTREOSCAN AND 99MTC-TEKTROTYDE IN TECHNICAL MATERS [RADIOLABELING, QUALITY CONTROL, INJECTED DOSES AND PATIENT RADIATION EXPOSURE] M. Papachristou, І. Xirafi, I. Datseris. Department of Nuclear Medicine e PET/CT General Hospital of Athens “Evaggelismos” Introduction: The imaging of positive SSTR's tumours with radiolabeled analogues of somatostatine has a broad use in oncology. The radiopharmaceutical of choice was 111In-DTPA-D-Phe-Octreotide. The use of 111In is facing some problems because it depends in cyclotron production which leads to restricted availability and very high cost. So to overcome these problems the use of 99mTc was selected as “easy- toget” radionuclide with low cost. The 99mTc-EDDA/HYNIC-Tyr3-Octreotide can image the tumours with SSTRs. We report a comparison between the 111In-Octreoscan and 99mTc-Tektrotyde in radiolabeling, quality control, injected doses and patient radiation exposure. Methods: The radiolabeling procedure of both radiopharmaceuticals were carried out according to the SPC of the products and the European Pharmacopeia. After the labelling, both drugs undergo quality control which includes pH measurements, visual control and instant thin layer chromatography (TLC), in order to be released. One vial 111In-Octreoscan is used for one single patient and one vial of 99m Tc-Tektrotyde is used for two patients. The dose of the 111In is ~5 mCi and the dose of 99mTc is ~ 20 mCi in accordance with our Department protocols. Results: To label 111In-Octreoscan takes 30 min and to label 99mTc-Tektrotyde takes almost 50 min. The quality control of 111In needs only one TLC
system (~ 20 min) where for the 99mTc needs two TLC systems (~ 40 min). The patient’s injected with111In have higher radiation exposure than the patients injected with 99mTc. The imaging protocol of 111In is a 2-day, one day longer than 99mTc (1-day protocol). Conclusions: 111In- Octreoscan is a well standardized and well know radiopharmaceutical with easy labelling procedure and quality control. Its cons are the 2-days protocol, the higher radiation exposure, the higher cost and the short availability. 99m Tc- Tektrotyde is a new radiopharmaceutical which isn’t well defined. Its radiolabeling procedure and quality control are long. 99mTc-Tektrotyde pros are the 1-day protocol, the lower radiation exposure, the lower cost for two patients and it's broad availability. Both radiopharmaceuticals have advantages and disadvantages. The choice depends on the Nuclear Medicine Department’s resources, protocols and qualification standards.
BLOODLESS MEASUREMENT OF HEMATOCRIT M. Adamopoulou a, G. Fountos b, E. Kounadi a, M. Rekkas a. a Ministry of Health in Greece, SEYYP, Athens, Greece; b Department of Biomedical Engineering, TEI of Athens, Greece Background: The direct estimation of the hematocrit at surgery without blood sampling procedures and laboratory analyzes, could yield significant time savings for the clinician, especially when managing emergencies. The purpose of this study is the construction of a biotechnology device, in order to determine the hematocrit value, in a bloodless non invasive method, that can be used for an immediate diagnosis. Materials and methods: Using technology similar to that of an “oxymeter”, we are in the process of manufacturing a portable device, which in contact with a large vase (jugular, femoral or brachial artery etc), will be able to count the number of red blood cells per cubic millimeter. The red blood cells are identified by their concave surface, separating them from the remaining blood cells (white blood cells , platelets, etc), where light scattering occurs in a different way. Results: After the completion of the prototype which called «Hemo-detector», measurements of hematocrit will be performed using this device to patients. The hematocrit values measured will be compared with them upon laboratory tests (blood draw) to assess the reliability of this novel non invasive method. Discussion: The immediate and bloodless measurement of hematocrit is an important help for the clinician where he will be able to evaluate a significant number of diseases. Also, pain and stress for the patient can be avoided. Furthermore, since this will be a low cost method resources for the patient as well as social health funds can be saved. THE ROLE OF DOSIMETRIC CALCULATIONS IN OPTIMIZING PEPTIDE RECEPTOR RADIONUCLIDE THERAPY BY [177LU-DOTA0, TYR3] OCTREOTATE Irini Baka a, Maria Argyrou a, Marina Michalitsi a, Alexia Valassi a, Agapi Ploussi a, Maria Lyra a, b. a Radiation Physics Unit, 1st Department of Radiology, Aretaieion hospital, University of Athens, Greece; b Nuclear Medicine Section, 1st Department of Radiology, Aretaieion hospital, University of Athens, Greece Aim: Response and toxicity prediction is essential to the implementation of Peptide Receptor Radionuclide Therapy (PRRT) for neuroendocrine tumors. Radiolabelled somatostatin analogue [177Lu-DOTA0, Tyr3] octreotate stands as a promising therapy tool. Specific dosimetry is a crucial factor in patient treatment planning. Dosimetric techniques implemented in our Institution are presented. Methods: In our Institution, neuroendocrine tumor treatment, by radiopeptide infusion via intrahepatic arterial catheterization, is a well established technique. Kidney protective agents are also included in our protocol. The individualized patient dosimetry calculations were based on planar and SPECT scintigraphy images. Counts were