Miroslav Hodek

Utilization of cone‐beam CT for reconstruction of dose distribution delivered in image‐guided radiotherapy of prostate carcinoma — bony landmark setup compared to fiducial markers setup

The purpose of this study was to compare two different styles of prostate IGRT: bony landmark (BL) setup vs. fiducial markers (FM) setup. Twenty‐nine prostate patients were treated with daily BL setup and 30 patients with daily FM setup. Delivered dose distribution was reconstructed on cone‐beam CT (CBCT) acquired once a week immediately after the alignment. Target dose coverage was evaluated by the proportion of the CTV encompassed by the 95% isodose. Original plans employed 1 cm safety margin. Alternative plans assuming smaller 7 mm margin between CTV and PTV were evaluated in the same way. Rectal and bladder volumes were compared with initial ones. While the margin reduction in case of BL setup makes the prostate coverage significantly worse (p=0.0003, McNemars test), in case of FM setup with the reduced 7 mm margin, the prostate coverage is even better compared to BL setup with 10 mm margin (p=0.049, Fishers exact test). Moreover, partial volumes of organs at risk irradiated with a specific dose can be significantly lowered (p<0.0001, unpaired t‐test). Reducing of safety margin is not acceptable in case of BL setup, while the margin can be lowered from 10 mm to 7 mm in case of FM setup. PACS numbers: 87.55.dk, 87.55.km, 87.55.tm

Hematopoietic recovery after transplantation CD117+B220- (LACZ*) bone marrow cells in lethally irradiated mice.

Experiments presented here were aimed at the description of hematopoiesis repair and in vivo homing of transplanted separated CD117+B220- bone marrow cells after whole-body lethal irradiation at LD 9Gy. ROSA 26 mice were used as donors of marrow cells for transplantation [B6;129S/Gt (ROSA)26Sor] and were tagged with lacZ gene, and F2 hybrid mice [B6129SF2/J] were used as recipients of bone marrow transplanted cells. Hematopoiesis repair was provided by transplantation, both suspension of whole bone marrow cells (5x106) and isolated CD117+B220- cells (5x104). Mice survived up to thirty days after irradiation. We demonstrated that transplantation of suspension of whole bone marrow cells led to faster recovery of CFU-GM (Granulocyte-macrophage colony forming units) in bone marrow and in the spleen too. It is not clear what the share of residential and transplanted cells is in the repair process. Our results demonstrate that sufficient hematopoietic repair occurs after transplantation of CD117+B220- (lacZ+) in lethally irradiated mice, and the difference in CFU-GM numbers in the bone marrow and spleen found on day 8 posttransplant has no influence on the survival of lethally irradiated mice (30 days follow-up).

Predicting factors for locoregional failure of high-dose-rate brachytherapy for early-stage oral cancer

AIM Brachytherapy is an alternative to surgery in the treatment of the early stages of oral tongue cancer. The aim of this retrospective study was to analyze the clinical risk factors and possible candidate biomarkers of local and regional tumor control. PATIENTS & METHODS Twenty-four patients were treated between the years 2001 and 2010. Median follow-up was 37.4 months. Correlation between disease-free survival and clinical stage, tumor grade, resection margin, depth of invasion, and p16, EGF receptor, NF-κB, HIF-1α, HER2, Ku-80, COX-2 and VEGF expression was evaluated. RESULTS The estimated 5-year local control was 81% and locoregional control was 62%. Depth of tumor invasion (p = 0.018) and higher VEGF expression (p = 0.016) were significantly predictive for worse disease-free survival in Cox multivariate analysis. CONCLUSION Intensity of VEGF expression and depth of tumor invasion may be significantly negative predictors of disease-free survival in tongue cancer patients treated by brachytherapy alone. Predictive value of VEGF deserves evaluation in larger studies.