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Nanoparticles for radiation therapy enhancement
P.F. Sharp / Physica Medica 32 (2016) 192–193
Other issues in tumor delineation are concerned with PET imaging performed with radiotracers different from 18FDG, for example 11C-choline and 11C-methionine for prostate and brain tumors imaging, for which the conclusions drawn for 18FDG imaging delineation may not apply and different techniques and strategies must be looked for. http://dx.doi.org/10.1016/j.ejmp.2016.07.340
PATIENT-SPECIFIC DOSIMETRY IN MOLECULAR RADIOTHERAPY: WHY AND HOW? Manuel Bardiès. INSERM – Centre de Recherches en Cancérologie de Toulouse, France According to Euratom Directive 2013/59: ‘‘For all medical exposure of patients for radiotherapeutic purposes, exposures of target volumes shall be individually planned and their delivery appropriately verified taking into account that doses to non-target volumes and tissues shall be as low as reasonably achievable and consistent with the intended radiotherapeutic purpose of the exposure” The Directive further defines ”radiotherapeutic means pertaining to radiotherapy, including nuclear medicine for therapeutic purposes”. Interestingly, this paragraph belongs to the ‘‘optimisation” part of the Directive. This obviously has consequences for radiopharmaceutical dosimetry implementation in nuclear medicine. The fact is that there is not a unique approach to patient-specific dosimetry. If the objective is to optimise the practice, then several possibilities must be considered: dosimetry can be implemented to assess efficacy or toxicity. This will lead to different dosimetric protocols. We will review various situations of molecular radiotherapy and associated dosimetric approaches. http://dx.doi.org/10.1016/j.ejmp.2016.07.341
NANOPARTICLES FOR RADIATION THERAPY ENHANCEMENT Kiki Theodorou. Medical Physics Dept., Medical School, University of Thessaly, Greece Nanoparticles (NPs) have been used for drug delivery, for in vitro diagnosis and for in vivo imaging. During the last decades, efforts have been made for the use of nanoparticles as therapeutic agents. Given that radiation therapy is not a selective antitumor treatment, the main challenge is to increase its therapeutic efficacy and thus to increase the differential radiation effect between healthy and cancer cells by the combined use of NPs. In the many research projects that have been contacted the last years, different nanoparticle designs and materials have been
193
employed but the main idea is the use of high-Z NPs for radiosensitization. In this context, these NPs can intensify the production of secondary electrons and ROS that in turn enhance radiation therapy effects. The enhancement of radiotherapy efficiency could be evaluated by the determination of the Nanoparticle-mediated Enhancement Ratio (NER) after a single radiation dose, the determination of the Dose Modifying Factor (DMF) based on survival curves and the variation of the ROS production upon irradiation. This review will focused on the different approaches followed on the use of nanoparticles, the dosimetric studies available, the radiobiological issues and the target selectivity. Discussion will be made on the efficiency and the prospective of the use of NPs in current radiotherapy practice. http://dx.doi.org/10.1016/j.ejmp.2016.07.342
AUTOMATED ANALYSIS OF OPHTHALMOLOGICAL IMAGES FOR EARLY SIGNS OF DIABETIC RETINOPATHY P.F. Sharp. Medical Physics, University of Aberdeen, UK Diabetic eye disease is the leading cause of blindness in the working age population. Early detection is important so a Scottish national screening service was set up ensuring that every person with diabetes has an annual retinal imaging. As this requires a person to examine every image it is time consuming and expensive. So we were asked to develop software to automatically detect early signs of eye disease from retinal images. Software was developed to assess the quality of retinal images and, if quality was sufficient, to identify the presence of diabetic eye disease, namely microaneurysms, exudates and haemorrhages. The software was evaluated on a series of 33,535 consecutive patients imaged at two Scottish screening centres. The results were compared with those given by manual screeners. The costs of implementing the software into the national screening programme were evaluated. It showed a detection rate of 99.8% for observable retinopathy, an early stage of disease which requires the person to undergo frequent monitoring, and 98.2% for referable retinopathy, where the person needs to be seen by an ophthalmologist. No cases of proliferative retinopathy, advanced disease, were missed. 12,185 patients would not have required seeing by manual screeners as they had no retinopathy. A health economics analysis showed that cost savings were in excess of £200,000 per annum. The software was shown to provide a cost-effective way of reducing the number of retinal images needing examination by a trained screener and is now routinely used by the screening service. http://dx.doi.org/10.1016/j.ejmp.2016.07.343
Other issues in tumor delineation are concerned with PET imaging performed with radiotracers different from 18FDG, for example 11C-choline and 11C-methionine for prostate and brain tumors imaging, for which the conclusions drawn for 18FDG imaging delineation may not apply and different techniques and strategies must be looked for. http://dx.doi.org/10.1016/j.ejmp.2016.07.340
PATIENT-SPECIFIC DOSIMETRY IN MOLECULAR RADIOTHERAPY: WHY AND HOW? Manuel Bardiès. INSERM – Centre de Recherches en Cancérologie de Toulouse, France According to Euratom Directive 2013/59: ‘‘For all medical exposure of patients for radiotherapeutic purposes, exposures of target volumes shall be individually planned and their delivery appropriately verified taking into account that doses to non-target volumes and tissues shall be as low as reasonably achievable and consistent with the intended radiotherapeutic purpose of the exposure” The Directive further defines ”radiotherapeutic means pertaining to radiotherapy, including nuclear medicine for therapeutic purposes”. Interestingly, this paragraph belongs to the ‘‘optimisation” part of the Directive. This obviously has consequences for radiopharmaceutical dosimetry implementation in nuclear medicine. The fact is that there is not a unique approach to patient-specific dosimetry. If the objective is to optimise the practice, then several possibilities must be considered: dosimetry can be implemented to assess efficacy or toxicity. This will lead to different dosimetric protocols. We will review various situations of molecular radiotherapy and associated dosimetric approaches. http://dx.doi.org/10.1016/j.ejmp.2016.07.341
NANOPARTICLES FOR RADIATION THERAPY ENHANCEMENT Kiki Theodorou. Medical Physics Dept., Medical School, University of Thessaly, Greece Nanoparticles (NPs) have been used for drug delivery, for in vitro diagnosis and for in vivo imaging. During the last decades, efforts have been made for the use of nanoparticles as therapeutic agents. Given that radiation therapy is not a selective antitumor treatment, the main challenge is to increase its therapeutic efficacy and thus to increase the differential radiation effect between healthy and cancer cells by the combined use of NPs. In the many research projects that have been contacted the last years, different nanoparticle designs and materials have been
193
employed but the main idea is the use of high-Z NPs for radiosensitization. In this context, these NPs can intensify the production of secondary electrons and ROS that in turn enhance radiation therapy effects. The enhancement of radiotherapy efficiency could be evaluated by the determination of the Nanoparticle-mediated Enhancement Ratio (NER) after a single radiation dose, the determination of the Dose Modifying Factor (DMF) based on survival curves and the variation of the ROS production upon irradiation. This review will focused on the different approaches followed on the use of nanoparticles, the dosimetric studies available, the radiobiological issues and the target selectivity. Discussion will be made on the efficiency and the prospective of the use of NPs in current radiotherapy practice. http://dx.doi.org/10.1016/j.ejmp.2016.07.342
AUTOMATED ANALYSIS OF OPHTHALMOLOGICAL IMAGES FOR EARLY SIGNS OF DIABETIC RETINOPATHY P.F. Sharp. Medical Physics, University of Aberdeen, UK Diabetic eye disease is the leading cause of blindness in the working age population. Early detection is important so a Scottish national screening service was set up ensuring that every person with diabetes has an annual retinal imaging. As this requires a person to examine every image it is time consuming and expensive. So we were asked to develop software to automatically detect early signs of eye disease from retinal images. Software was developed to assess the quality of retinal images and, if quality was sufficient, to identify the presence of diabetic eye disease, namely microaneurysms, exudates and haemorrhages. The software was evaluated on a series of 33,535 consecutive patients imaged at two Scottish screening centres. The results were compared with those given by manual screeners. The costs of implementing the software into the national screening programme were evaluated. It showed a detection rate of 99.8% for observable retinopathy, an early stage of disease which requires the person to undergo frequent monitoring, and 98.2% for referable retinopathy, where the person needs to be seen by an ophthalmologist. No cases of proliferative retinopathy, advanced disease, were missed. 12,185 patients would not have required seeing by manual screeners as they had no retinopathy. A health economics analysis showed that cost savings were in excess of £200,000 per annum. The software was shown to provide a cost-effective way of reducing the number of retinal images needing examination by a trained screener and is now routinely used by the screening service. http://dx.doi.org/10.1016/j.ejmp.2016.07.343