To evaluate the predictive value of dose–volume histogram (DVH) parameters for late side effects ... more To evaluate the predictive value of dose–volume histogram (DVH) parameters for late side effects of the rectum, sigmoid colon, and bladder in image-guided brachytherapy for cervix cancer patients.A total of 141 patients received external-beam radiotherapy and image-guided brachytherapy with or without chemotherapy. The DVH parameters for the most exposed 2, 1, and 0.1 cm3 (D2cc, D1cc, and D0.1cc) of the rectum, sigmoid, and bladder, as well as International Commission on Radiation Units and Measurements point doses (DICRU) were computed. Total doses were converted to equivalent doses in 2 Gy by applying the linear-quadratic model (α/β = 3 Gy). Late side effects were prospectively assessed using the Late Effects in Normal Tissues–Subjective, Objective, Management and Analytic score. The following patient groups were defined: Group 1: no side effects (Grade 0); Group 2: side effects (Grade 1–4); Group 3: minor side effects (Grade 0–1); and Group 4: major side effects (Grade 2–4).The median follow-up was 51 months. The overall 5-year actuarial side effect rates were 12% for rectum, 3% for sigmoid, and 23% for bladder. The mean total D2cc were 65 ± 12 Gy for rectum, 62 ± 12 Gy for sigmoid, and 95 ± 22 Gy for bladder. For rectum, statistically significant differences were observed between Groups 1 and 2 in all DVH parameters and DICRU. Between Groups 3 and 4, no difference was observed for D0.1cc. For sigmoid, significant differences were observed for D2cc and D1cc, but not for D0.1cc in all groups. For bladder, significant differences were observed for all DVH parameters only comparing Groups 3 and 4. No differences were observed for DICRU.The parameters D2cc and D1cc have a good predictive value for rectal toxicity. For sigmoid, no prediction could be postulated because of limited data. In bladder, DVH parameters were predictive only for major toxicity.
Several different aspects of the current state of optical materials are addressed. The discussion... more Several different aspects of the current state of optical materials are addressed. The discussion on plastics for optical applications brought out that, while plastic lenses are playing an increasing role in optical systems, quality assurance techniques need improvement. Silica glasses have received attention because of such developments as linear index gradients. The effects of ionizing radiation and the use of X-ray fine structure for studying disorder are also discussed. Crystalline material parameters are considered to be essential for designing active optical devices. Emphasis is placed on the non-optical properties of materials used in optical devices.
Radiotheraphy and Oncology Journal of the European Society For Therapeutic Radiology and Oncology, 2006
The second part of the GYN GEC ESTRO working group recommendations is focused on 3D dose-volume p... more The second part of the GYN GEC ESTRO working group recommendations is focused on 3D dose-volume parameters for brachytherapy of cervical carcinoma. Methods and parameters have been developed and validated from dosimetric, imaging and clinical experience from different institutions (University of Vienna, IGR Paris, University of Leuven). Cumulative dose volume histograms (DVH) are recommended for evaluation of the complex dose heterogeneity. DVH parameters for GTV, HR CTV and IR CTV are the minimum dose delivered to 90 and 100% of the respective volume: D90, D100. The volume, which is enclosed by 150 or 200% of the prescribed dose (V150, V200), is recommended for overall assessment of high dose volumes. V100 is recommended for quality assessment only within a given treatment schedule. For Organs at Risk (OAR) the minimum dose in the most irradiated tissue volume is recommended for reporting: 0.1, 1, and 2 cm3; optional 5 and 10 cm3. Underlying assumptions are: full dose of external beam therapy in the volume of interest, identical location during fractionated brachytherapy, contiguous volumes and contouring of organ walls for >2 cm3. Dose values are reported as absorbed dose and also taking into account different dose rates. The linear-quadratic radiobiological model-equivalent dose (EQD2)-is applied for brachytherapy and is also used for calculating dose from external beam therapy. This formalism allows systematic assessment within one patient, one centre and comparison between different centres with analysis of dose volume relations for GTV, CTV, and OAR. Recommendations for the transition period from traditional to 3D image-based cervix cancer brachytherapy are formulated. Supplementary data (available in the electronic version of this paper) deals with aspects of 3D imaging, radiation physics, radiation biology, dose at reference points and dimensions and volumes for the GTV and CTV (adding to [Haie-Meder C, Pötter R, Van Limbergen E et al. Recommendations from Gynaecological (GYN) GEC ESTRO Working Group (I): concepts and terms in 3D image-based 3D treatment planning in cervix cancer brachytherapy with emphasis on MRI assessment of GTV and CTV. Radiother Oncol 2005;74:235-245]). It is expected that the therapeutic ratio including target coverage and sparing of organs at risk can be significantly improved, if radiation dose is prescribed to a 3D image-based CTV taking into account dose volume constraints for OAR. However, prospective use of these recommendations in the clinical context is warranted, to further explore and develop the potential of 3D image-based cervix cancer brachytherapy.
The &... more The "International Summer School on Experimental and Clinical Oncology for Medical Students" is organised at the Medical University of Vienna to teach a multidisciplinary approach to oncology to medical students in the final phase of their studies. The program includes biology, diagnosis, clinical and psycho-oncology. Lectures are given by medical, radiation and surgical oncologists. Teaching includes case reports, poster presentations and role-play. As part of the organising committee, Austrian students organise a social program. Since 1999, six courses have been held (147 students from 19 countries). Students recorded high satisfaction with organisation, scientific content and topic range. Case presentations, poster presentations and role-play were very useful. Early criticism that the program was too intense (long lectures and little interaction) has been answered. The summer school has a high degree of acceptance and is a very useful tool to teach medical students about oncology and approaching a cancer patient.
To evaluate the predictive value of dose–volume histogram (DVH) parameters for late side effects ... more To evaluate the predictive value of dose–volume histogram (DVH) parameters for late side effects of the rectum, sigmoid colon, and bladder in image-guided brachytherapy for cervix cancer patients.A total of 141 patients received external-beam radiotherapy and image-guided brachytherapy with or without chemotherapy. The DVH parameters for the most exposed 2, 1, and 0.1 cm3 (D2cc, D1cc, and D0.1cc) of the rectum, sigmoid, and bladder, as well as International Commission on Radiation Units and Measurements point doses (DICRU) were computed. Total doses were converted to equivalent doses in 2 Gy by applying the linear-quadratic model (α/β = 3 Gy). Late side effects were prospectively assessed using the Late Effects in Normal Tissues–Subjective, Objective, Management and Analytic score. The following patient groups were defined: Group 1: no side effects (Grade 0); Group 2: side effects (Grade 1–4); Group 3: minor side effects (Grade 0–1); and Group 4: major side effects (Grade 2–4).The median follow-up was 51 months. The overall 5-year actuarial side effect rates were 12% for rectum, 3% for sigmoid, and 23% for bladder. The mean total D2cc were 65 ± 12 Gy for rectum, 62 ± 12 Gy for sigmoid, and 95 ± 22 Gy for bladder. For rectum, statistically significant differences were observed between Groups 1 and 2 in all DVH parameters and DICRU. Between Groups 3 and 4, no difference was observed for D0.1cc. For sigmoid, significant differences were observed for D2cc and D1cc, but not for D0.1cc in all groups. For bladder, significant differences were observed for all DVH parameters only comparing Groups 3 and 4. No differences were observed for DICRU.The parameters D2cc and D1cc have a good predictive value for rectal toxicity. For sigmoid, no prediction could be postulated because of limited data. In bladder, DVH parameters were predictive only for major toxicity.
Several different aspects of the current state of optical materials are addressed. The discussion... more Several different aspects of the current state of optical materials are addressed. The discussion on plastics for optical applications brought out that, while plastic lenses are playing an increasing role in optical systems, quality assurance techniques need improvement. Silica glasses have received attention because of such developments as linear index gradients. The effects of ionizing radiation and the use of X-ray fine structure for studying disorder are also discussed. Crystalline material parameters are considered to be essential for designing active optical devices. Emphasis is placed on the non-optical properties of materials used in optical devices.
Radiotheraphy and Oncology Journal of the European Society For Therapeutic Radiology and Oncology, 2006
The second part of the GYN GEC ESTRO working group recommendations is focused on 3D dose-volume p... more The second part of the GYN GEC ESTRO working group recommendations is focused on 3D dose-volume parameters for brachytherapy of cervical carcinoma. Methods and parameters have been developed and validated from dosimetric, imaging and clinical experience from different institutions (University of Vienna, IGR Paris, University of Leuven). Cumulative dose volume histograms (DVH) are recommended for evaluation of the complex dose heterogeneity. DVH parameters for GTV, HR CTV and IR CTV are the minimum dose delivered to 90 and 100% of the respective volume: D90, D100. The volume, which is enclosed by 150 or 200% of the prescribed dose (V150, V200), is recommended for overall assessment of high dose volumes. V100 is recommended for quality assessment only within a given treatment schedule. For Organs at Risk (OAR) the minimum dose in the most irradiated tissue volume is recommended for reporting: 0.1, 1, and 2 cm3; optional 5 and 10 cm3. Underlying assumptions are: full dose of external beam therapy in the volume of interest, identical location during fractionated brachytherapy, contiguous volumes and contouring of organ walls for >2 cm3. Dose values are reported as absorbed dose and also taking into account different dose rates. The linear-quadratic radiobiological model-equivalent dose (EQD2)-is applied for brachytherapy and is also used for calculating dose from external beam therapy. This formalism allows systematic assessment within one patient, one centre and comparison between different centres with analysis of dose volume relations for GTV, CTV, and OAR. Recommendations for the transition period from traditional to 3D image-based cervix cancer brachytherapy are formulated. Supplementary data (available in the electronic version of this paper) deals with aspects of 3D imaging, radiation physics, radiation biology, dose at reference points and dimensions and volumes for the GTV and CTV (adding to [Haie-Meder C, Pötter R, Van Limbergen E et al. Recommendations from Gynaecological (GYN) GEC ESTRO Working Group (I): concepts and terms in 3D image-based 3D treatment planning in cervix cancer brachytherapy with emphasis on MRI assessment of GTV and CTV. Radiother Oncol 2005;74:235-245]). It is expected that the therapeutic ratio including target coverage and sparing of organs at risk can be significantly improved, if radiation dose is prescribed to a 3D image-based CTV taking into account dose volume constraints for OAR. However, prospective use of these recommendations in the clinical context is warranted, to further explore and develop the potential of 3D image-based cervix cancer brachytherapy.
The &... more The "International Summer School on Experimental and Clinical Oncology for Medical Students" is organised at the Medical University of Vienna to teach a multidisciplinary approach to oncology to medical students in the final phase of their studies. The program includes biology, diagnosis, clinical and psycho-oncology. Lectures are given by medical, radiation and surgical oncologists. Teaching includes case reports, poster presentations and role-play. As part of the organising committee, Austrian students organise a social program. Since 1999, six courses have been held (147 students from 19 countries). Students recorded high satisfaction with organisation, scientific content and topic range. Case presentations, poster presentations and role-play were very useful. Early criticism that the program was too intense (long lectures and little interaction) has been answered. The summer school has a high degree of acceptance and is a very useful tool to teach medical students about oncology and approaching a cancer patient.
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