Time filter

Source Type

Sankt Gallen, Switzerland

Putora P.M.,Klinik fur Radio Onkologie | Fruh M.,Kantonsspital St. Gallen | Muller J.,Kantonsspital St. Gallen
Respirology | Year: 2013

Previous reports suggest a correlation between positron emission tomography with fluorodeoxyglucose maximum standardized uptake value (SUVmax) and epidermal growth factor receptor (EGFR) mutation status in lung cancer. We analysed positron emission tomography with fluorodeoxyglucose SUVmax in 14 patients with EGFR mutations, and a control group of 14 subjects with wild-type EGFR adenocarcinomas. The mean SUV value was 10.7 for EGFR-mutated adenocarcinomas and 9.9 for wild-type tumours. There was no correlation between SUV values and EGFR mutation status. Omitting EGFR testing in lung cancers with low SUVmax is not appropriate. © 2013 Asian Pacific Society of Respirology.

Corradini S.,Ludwig Maximilians University of Munich | Belka C.,Ludwig Maximilians University of Munich | Plasswilm L.,Klinik fur Radio Onkologie
Onkologe | Year: 2010

The treatment of choice for solitary plasmacytoma is radiation therapy. The local response rate exceeds 90%. Solitary plasmacytoma is characterized by the neoplastic proliferation of a single clone of plasma cells involving invasion of skeletal structures or extramedullary soft tissues. Progression to multiple myeloma is more common in solitary plasmacytoma of the bone than in extramedullary plasmacytoma. In the treatment of multiple myeloma radiotherapy is effective in palliating local symptoms, such as painful bone metastases, radiculopathy and spinal cord compression. Long-course radiotherapy (10x3 Gy, 20x2 Gy) results in better outcome of pain relief, recalcification rates and local control rates. Patients with a poor survival prognosis benefit from short-course radiotherapy (1x8 Gy, 4x5 Gy). Total body radiation as part of conditioning protocols prior to autologous blood stem cell transplantation is no longer a treatment of choice. © Springer-Verlag 2010.

Schiefer H.,Klinik fur Radio Onkologie | Fogliata A.,Oncology Institute of Southern Switzerland | Nicolini G.,Oncology Institute of Southern Switzerland | Cozzi L.,Oncology Institute of Southern Switzerland | And 12 more authors.
Medical Physics | Year: 2010

Purpose: In 2008, a national intensity modulated radiation therapy (IMRT) dosimetry intercomparison was carried out for all 23 radiation oncology institutions in Switzerland. It was the aim to check the treatment chain focused on the planning, dose calculation, and irradiation process. Methods: A thorax phantom with inhomogeneities was used, in which thermoluminescence dosimeter (TLD) and ionization chamber measurements were performed. Additionally, absolute dosimetry of the applied beams has been checked. Altogether, 30 plan-measurement combinations have been used in the comparison study. The results have been grouped according to dose calculation algorithms, classified as "type a" or "type b," as proposed by Knöös ["Comparison of dose calculation algorithms for treatment planning in external photon beam therapy for clinical situations," Phys. Med. Biol. 51, 5785-5807 (2006)]. Results: Absolute dosimetry check under standard conditions: The mean ratio between the dose derived from the single field measurement and the stated dose, calculated with the treatment planning system, was 1.007±0.010 for the ionization chamber and 1.002±0.014 (mean±standard deviation) for the TLD measurements. IMRT Plan Check: In the lung tissue of the planning target volume, a significantly better agreement between measurements (TLD, ionization chamber) and calculations is shown for type b algorithms than for type a (p<0.001). In regions outside the lungs, the absolute differences between TLD measured and stated dose values, relative to the prescribed dose, |(Dm - Ds)/D prescribed|, are 1.9±0.4% and 1.4±0.3%, respectively. These data show the same degree of accuracy between the two algorithm types if low-density medium is not present. Conclusions: The results demonstrate that the performed intercomparison is feasible and confirm the calculation accuracies of type a and type b algorithms in a water equivalent and low-density environment. It is now planned to offer the intercomparison on a regular basis to all Swiss institutions using IMRT techniques. © 2010 American Association of Physicists in Medicine.

Plasswilm L.,Klinik fur Radio Onkologie | Schmid H.-P.,Klinik fur Urologie | Schwab C.,Klinik fur Urologie | Putora P.M.,Klinik fur Radio Onkologie
Journal fur Urologie und Urogynakologie | Year: 2015

Localized prostate cancer is classified into 3 risk groups: low, intermediate, and high, based on pre-treatment clinical parameters. The question of who benefits from the addition of androgen deprivation therapy (ADT) to local treatment is of high clinical relevance. Multiple trials have investigated the impact and duration of neoadjuvant, concurrent, or adjuvant ADT to radiotherapy. Based on these trials, in the presence of risk factors the addition of ADT to radiotherapy can be recommended and improves prognosis. High-risk prostate cancer patients benefit from 2-3 years of ADT, while intermediate-risk patients benefit from 4-6 months of ADT. Every recommendation needs to take into account the patient-specific characteristics, such as comorbidity, age, life expectancy, and patient preference. The value of ADT in addition to radiotherapy of the pelvis (pelvic lymph node irradiation) is currently unclear. Patients with low-risk prostate cancer do not benefit from the addition of ADT to local treatment (LDR brachytherapy, external beam radiotherapy, or radical prostatectomy). After radical prostatectomy, ADT is recommended for patients with pN1 disease. The role of ADT in addition to postoperative radiotherapy is currently unclear.

Schiefer H.,Klinik fur Radio Onkologie | Ingulfsen N.,Kantonsschule Am Burggraben St.Gallen | Kluckert J.,Kantonsschule Am Burggraben St.Gallen | Peters S.,Klinik fur Radio Onkologie | Plasswilm L.,Klinik fur Radio Onkologie
Medical Physics | Year: 2015

Purpose: For stereotactic radiosurgery, the AAPM Report No. 54 [AAPM Task Group 42 (AAPM, 1995)] requires the overall stability of the isocenter (couch, gantry, and collimator) to be within a 1 mm radius. In reality, a rotating system has no rigid axis and thus no isocenter point which is fixed in space. As a consequence, the isocenter concept is reviewed here. It is the aim to develop a measurement method following the revised definitions. Methods: The mechanical isocenter is defined here by the point which rotates on the shortest path in the room coordinate system. The path is labeled as "isocenter path." Its center of gravity is assumed to be the mechanical isocenter. Following this definition, an image-based and radiation-free measurement method was developed. Multiple marker pairs in a plane perpendicular to the assumed gantry rotation axis of a linear accelerator are imaged with a smartphone application from several rotation angles. Each marker pair represents an independent measuring system. The room coordinates of the isocenter path and the mechanical isocenter are calculated based on the marker coordinates. The presented measurement method is by this means strictly focused on the mechanical isocenter. Results: The measurement result is available virtually immediately following completion of measurement. When 12 independent measurement systems are evaluated, the standard deviations of the isocenter path points and mechanical isocenter coordinates are 0.02 and 0.002 mm, respectively. Conclusions: The measurement is highly accurate, time efficient, and simple to adapt. It is therefore suitable for regular checks of the mechanical isocenter characteristics of the gantry and collimator rotation axis. When the isocenter path is reproducible and its extent is in the range of the needed geometrical accuracy, it should be taken into account in the planning process. This is especially true for stereotactic treatments and radiosurgery. © 2015 American Association of Physicists in Medicine.

Discover hidden collaborations