A comparison of tandem ring and tandem ovoid treatment as a curative brachytherapy component for cervical cancer.

PURPOSE: The standard treatment for locally advanced stage cervical cancer is definitive radiotherapy, the quality of which affects both survival and side effects. Brachytherapy is a major component of definitive radiotherapy; it is administered using different techniques and applicators. The purpose of this study was to dosimetrically compare tandem ovoid (T-ovoid) and tandem ring (T-ring) brachytherapy treatments. MATERIAL AND METHODS: Both applicator sets were applied to the same 20 patients, and treatment plans were made three-dimensionally (3D), with high-risk clinical target volume (HR-CTV) and organs at risk contoured. The HR-CTV was defined according to post-external magnetic resonance results. The patients with residual tumors not exceeding one-third of the parametrium were included in this study, while patients with larger masses were excluded and received interstitial therapy. The doses were calculated for both plans. Optimization for the HR-CTV was made with the aim that the equivalent dose according to 2 Gy (EQD2) of 90% of the HR-CTV (D90) would be higher than 85 Gy, without exceeding the maximum dose for organs at risk. Then, pairwise dosimetric comparisons were performed. RESULTS: Plans were compared dosimetrically according to the HR-CTV, point A and B doses, and organs at risk. Although the point A and B doses were higher with T-ovoid use, the 3D HR-CTV coverage was statistically better with T-ring application (EQD2 of HR-CTV D90: 97.46 Gy for T-ring and 88.44 Gy for T-ovoid; p < 0.0001). In addition, the rectum and bladder doses were statistically lower with T-ring usage (EQD2 of rectum, 2 cc; T-ring, 63.10 Gy; T-ovoid, 74.99 Gy; p < 0.0001; EQD2 of bladder, 2 cc; T-ring, 85.26 Gy; T-ovoid, 89.05 Gy; p < 0.0001). CONCLUSIONS: In our study with a limited number of samples, T-ring applicator seems to offer better 3D brachytherapy dosimetry for both HR-CTV and nearby organs at risk.

Malignant lymphoma associated with Behçet's disease: A report of 2 cases.

Herein we report 2 cases of malignant lymphoma associated with Behçet's disease. Case 1, a 53-yearold man, was diagnosed as Behçet's disease at the age of 26 years, and was treated with cyclophosphamide and prednisolone. At 45 years of age, bilateral enlarged lymph nodes were observed in the patient's neck. Evaluation of a lymph node biopsy specimen showed Hodgkin's disease and chemotherapy was administered. Due to disease recurrence 7 years later, chemotherapy and radiotherapy were administered. Case 2, a 67-year-old male, was diagnosed as Behçet's disease at age 44 years and began colchicine treatment. At 60 years of age a mass in his left tonsillar fossa was noted. Evaluation of a left tonsil biopsy specimen showed malignant lymphoma. Radiotherapy and chemotherapy were subsequently administered. At the time this report was written both patients were disease-free. Malignant lymphoma associated with Behçet's disease is rare-only 17 cases have been published. In addition to the presented cases, the literature regarding malignant lymphoma associated with Behçet's disease is reviewed.

Can radiotherapy affect the apical sealing ability of resin-based root canal sealers?

BACKGROUND: The authors conducted a study to assess the influence of radiotherapy on the apical sealing ability of one recently introduced resin-based root canal sealer and two sealers that have been in use for several years. METHODS: The authors divided 90 human maxillary anterior teeth into three groups according to the type of root canal sealer used and, using lateral condensation, obturated the roots with gutta-percha. They randomly divided all roots into two main groups according to the presence or absence of radiotherapy. For the groups that received irradiation, a dose of 60 gray was delivered in fractions of 1.8 Gy per day, five days a week for seven weeks. The authors then performed the centrifuging dye penetration test to determine apical leakage for each specimen. RESULTS: The authors compared the specimens in the groups that received radiotherapy after endodontic treatment with the specimens in the groups that did not undergo radiotherapy after endodontic treatment. They found that mean apical leakage was slightly higher in the radiotherapy groups, but they did not observe any statistical difference between the groups (P > .05). In the groups that did not undergo radiotherapy, the mean apical leakage for the specimens in the MM-Seal (MicroMega, Besançon, France [not marketed in the United States]), AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany) and AH 26 (Dentsply DeTrey GmbH) groups was 2.52 +/- 0.42 millimeters, 2.85 +/- 0.52 mm and 3.73 +/- 0.41 mm, respectively. In the groups that underwent radiotherapy, the mean apical leakage for the specimens in the MM-Seal, AH Plus and AH 26 groups was 2.72 +/- 0.55 mm, 2.96 +/- 0.47 mm and 3.93 +/- 0.61 mm, respectively. CONCLUSION: The apical sealing ability of the resin-based root canal sealers decreased slightly when radiotherapy was administered, although there was no statistically significant difference. CLINICAL IMPLICATIONS: Clinicians can safely use a resin-based root canal sealer in patients receiving radiotherapy.

Influence of radiation on bond strength.

PURPOSE: The aim of this in vitro study was to evaluate the shear bond strength of two adhesive systems--Prime & Bond NT (PBNT) and Clearfil SE Bond (CSEB)--to dentin irradiated before or after adhesive application. MATERIALS AND METHODS: Thirty extracted molars were sectioned mesiodistally with a diamond bur. The inner surface of each tooth's dentin was ground flat with SiC abrasive papers. The roots of the sectioned teeth were mounted in a cylindrical mold using chemically cured acrylic resin. In groups A1 and B1, a radiation dose of 60 Gy (R) was applied to the dentin surfaces at this point. In all groups, adhesives were applied according to the respective manufacturer's instructions. Cylindrical composite resin restorations (CRR; internal diameter 3 mm, height 4 mm) were then placed on the center of the flattened dentin surfaces. At this point, groups A2 and B2 received 60 Gy of radiation, and groups C1 and C2 remained as nonirradiated controls. Thus, the test groups were: A1: R + PBNT (Primed Bond NT) + CRR; A2: PBNT + CRR + R; B1: R + CSEB (Clearfil SE Bond) + CRR; B2: CSEB + CRR + R; C1: PBNT+ CRR; C2: CSEB+ CRR. Specimens were mounted in a universal testing machine and shear load was applied at a crosshead speed of 1 mm/min until failure. Bond strength values were calculated as MPa and the results were evaluated statistically using repeated measures of two-way ANOVA, with significance set at p < 0.05. RESULTS: Irradiation significantly affected adhesion of composite to dentin in groups A1 and A2 (p = 0.002). Group A1 showed statistically lower bond strength than group A2 (p < 0.05). No statistically significant differences were found among the other groups (p = 0.49). CONCLUSION: The time point of irradiation can have an adverse effect on bond strength, depending on the type of adhesive material.