Measurement of radiation dose with BeO dosimeters using optically stimulated luminescence technique in radiotherapy applications.

The radiation dose delivered to the target by using different radiotherapy applications has been measured with the help of beryllium oxide (BeO) dosimeters to be placed inside the rando phantom. Three-Dimensional Conformal Radiotherapy (3DCRT), Intensity-Modulated Radiotherapy (IMRT) and Intensity-Modulated Arc Therapy (IMAT) have been used as radiotherapy application. Individual treatment plans have been made for the three radiotherapy applications of rando phantom. The section 4 on the phantom was selected as target and 200 cGy doses were delivered. After the dosimeters placed on section 4 (target) and the sections 2 and 6 (non-target) were irradiated, the result was read through the OSL technique on the Risø TL/OSL system. This procedure was repeated three times for each radiotherapy application. The doses delivered to the target and the non-target sections as a result of the 3DCRT, IMRT and IMAT plans were analyzed. The doses received by the target were measured as 204.71 cGy, 204.76 cGy and 205.65 cGy, respectively. The dose values obtained from treatment planning system (TPS) were compared to the dose values obtained using the OSL technique. It has been concluded that, the radiation dose can be measured with the OSL technique by using BeO dosimeters in medical practices.

PET-CT guided curative conformal radiation therapy in limited stage small cell lung cancer.

BACKGROUND: The prognosis of small cell lung cancer (SCLC) has been improving with the advances in diagnostic and therapeutic modalities. Positron emission tomography/computed tomography (FDG-PET/CT) which has been studied in non-small cell lung cancer (NSCLC) for a long time, and it has only recently been applied to SCLC. Therefore we sought to observe firstly the prognostic importance of the FDG uptake in limited disease small cell lung cancer (LD-SCLC) patients and secondly the clinical outcomes and toxicity profiles of LD-SCLC patients treated with conformal radiation therapy (RT) using FDG-PET/CT simulation. METHODS: Between 2009 and 2011, 33 LD-SCLC patients with LD-SCLC underwent disease staging using FDG-PET/CT conformal RT. Thoracic radiation was administered at a daily fraction of 2 Gy. Total dose was prescribed according to the treatment protocol such as, concurrent or sequential chemotherapy and in some patients according to the response of CT. All patients underwent chemotherapy. Survival was estimated using the Kaplan-Meier method. RESULTS: The median age of the patients was 58 years (range, 38-77 years). The median follow-up time was 20 months (range, 6.6-47.6 months). The 3-year overall survival (OS) and locoregional control rates were 23% and 48%, respectively. CONCLUSIONS: There are few studies examining the impact of PET-CT and the prognostic significance of FDG-uptake on outcomes in patients with LD-SCLC. Higher RT doses in response to higher FDG uptake may be safely applied for the purpose of locoregional control.

Change in blood chemistry may explain higher toxicity of total body irradiation for bone marrow transplantation.

Total body irradiation (TBI) is a well established conditioning regimen for patients who had undergone bone marrow transplantation. TBI not only offers a slightly significant survival advantage over Busulphan-based conditioning regimens but also lower toxicity profile. However the biological process after TBI seems rather different than conventional routine partial body irradiation. Not only the tolerance doses but also time to occurrence of the organ toxicities show a variation. It has been shown that there are alterations in trace element content in kidney after TBI in addition to cytokines and redox-active metal composition of blood. Acute phase proteins also have been shown to rise after irradiation. Considering all these evidences we suggest that TBI changes the blood content of trace elements, acute phase response proteins with probably many other inflammatory proteins and cytokines within the blood and this change in blood content may sensitize the organs to radiation.