Background: The re-occurrence of an inflammatory skin reaction which is limited to previously irradiated areas after the administration of a promoting agent is called radiation recall dermatitis. Despite a number of case reports no systematic analysis about the frequency of the phenomenon exists. Therefore we performed an observation study in order to obtain information about this phenomenon in clinical practice. Patients and Methods: 142 patients who underwent palliative radiotherapy were included in the study. The skin reaction at the day of completion of radiotherapy was documented and the patients were followed until cytotoxic chemotherapy was administered or at least 6 months. Results: 91 patients received different types of chemotherapy. In 8 patients a radiation recall dermatitis was observed, corresponding to a frequency of 8.8%. The radiation skin reactions occurred within 6 weeks after the completion of radiotherapy which corresponded to the time-period most of the chemotherapies were applied in. The grade of observed radiation recall dermatitis ranged from a mild erythema to a severe exfoliative dermatitis. Conclusion: The radiation recall dermatitis is a reaction of moderate frequency among adult cancer patients. Its possible severity as well as consecutive therapeutic consequences argue for its consideration in clinical settings.

The purpose of this study was to investigate the dosimetric characteristics (energy dependence, linearity, fading, reproducibility, etc) of MOSFET detectors for in vivo dosimetry in the kV x-ray range. The experience of MOSFET in vivo dosimetry in a pre-clinical study using the Alderson phantom and in clinical practice is also reported. All measurements were performed with a Gulmay D3300 kV unit and TN-502RDI MOSFET detectors. For the determination of correction factors different solid phantoms and a calibrated Farmer-type chamber were used. The MOSFET signal was linear with applied dose in the range from 0.2 to 2 Gy for all energies. Due to fading it is recommended to read the MOSFET signal during the first 15 min after irradiation. For long time intervals between irradiation and readout the fading can vary largely with the detector. The temperature dependence of the detector signal was small (0.3% degrees C(-1)) in the temperature range between 22 and 40 degrees C. The variation of the measuring signal with beam incidence amounts to +/-5% and should be considered in clinical applications. Finally, for entrance dose measurements energy-dependent calibration factors, correction factors for field size and irradiated cable length were applied. The overall accuracy, for all measurements, was dominated by reproducibility as a function of applied dose. During the pre-clinical in vivo study, the agreement between MOSFET and TLD measurements was well within 3%. The results of MOSFET measurements, to determine the dosimetric characteristics as well as clinical applications, showed that MOSFET detectors are suitable for in vivo dosimetry in the kV range. However, some energy-dependent dosimetry effects need to be considered and corrected for. Due to reproducibility effects at low dose levels accurate in vivo measurements are only possible if the applied dose is equal to or larger than 2 Gy.