HIGHLIGHTS: • Intrabeam x-ray source and spherical applicators were simulated and skin dose was calculated. • Skin dose for constant skin to applicator distance strongly depends on applicator size. • Use of larger applicators generally results in higher skin dose. • The recommended 0.5-1 cm skin to applicator distance does not guarantee skin safety.
METHODS: Dose measurement of a standard pear-shaped plan carried out in phantom to verify the MOSkin dose measurement accuracy. With MOSkin attached to the third diode, RP3 of the PTW 9112, both detectors were inserted into patients' rectum. The RP3 and MOSkin measured doses in 18 sessions as well as the maximum measured doses from PTW 9112, RPmax in 48 sessions were compared to the planned doses.
RESULTS: Percentage dose differences ΔD (%) in phantom study for two MOSkin found to be 2.22 ± 0.07% and 2.5 ± 0.07%. IVD of 18 sessions resulted in ΔD(%) of -16.3% to 14.9% with MOSkin and ΔD(%) of -35.7% to -2.1% with RP3. In 48 sessions, RPmax recorded ΔD(%) of -37.1% to 11.0%. MOSkin_measured doses were higher in 44.4% (8/18) sessions, while RP3_measured were lower than planned doses in all sessions. RPmax_measured were lower in 87.5% of applications (42/47).
CONCLUSIONS: The delivered doses proven to deviate from planned doses due to unavoidable shift between imaging and treatment as measured with MOSkin and PTW 9112 detectors. The integration of MOSkin on commercial PTW 9112 surface found to be feasible for rectal dose IVD during cervical HDR ICBT.
Methods: In vitro models of breast cancer cell lines (MCF-7, MDA-MB-231) and normal fibroblast cell line (NIH/3T3) were employed. Cellular localization and cytotoxicity studies were conducted prior to inspection on the radiosensitization effects and generation of reactive oxygen species (ROS) on three proposed radiosensitizers: BiONPs, Cis, and BiONPs-Cis combination (BC). The optimal, non-cytotoxic concentration of BiONPs (0.5 mM) and the 25% inhibitory concentration of Cis (1.30 µM) were applied. The radiosensitization effects were evaluated by using a 0.38 MeV Iridium-192 HDR brachytherapy source over a prescribed dose range of 0 Gy to 4 Gy.
Results: The cellular localization of BiONPs was visualized by light microscopy and accumulation of the BiONPs within the vicinity of the nuclear membrane was observed. Quantification of the sensitization enhancement ratio extrapolated from the survival curves indicates radiosensitization effects for MCF-7 and MDA-MB-231 when treated with BiONPs, Cis, and BC. However, NIH/3T3 cells exhibited contradictive behavior as it only reacted towards the BC combination. Nonetheless, the MCF-7 cell line loaded with BC shows the highest SER of 4.29. ROS production analysis, on the other hand, shows that Cis and BC radiosensitizers generated the highest free radicals in comparison to BiONPs alone.
Conclusion: A BiONPs-Cis combination was unveiled as a novel approach that offers promising radiosensitization enhancement that will increase the efficiency of tumor control while preserving the normal tissue at a reduced dose. This data is the first precedent to prove the synergetic implication of BiONPs, Cis, and HDR brachytherapy that will be beneficial for future chemoradiotherapy strategies in cancer care.
METHODS AND MATERIALS: Between October 2007 and May 2016, 106 patients with untreated squamous cell carcinoma of the cervix were enrolled in the present study. Radiation therapy consisted of pelvic irradiation (total dose, 50 Gy in 25 fractions including central shielding), prophylactic paraortic regional irradiation (36-40 Gy in 20 fractions), and either high- or low-dose-rate intracavitary brachytherapy (ICBT) according to institutional practice. The planned point A dose was 21 to 28 Gy in 3 to 4 fractions for high-dose-rate ICBT and 40 to 41 Gy in 1 to 2 fractions for low-dose-rate ICBT. Five cycles of weekly cisplatin (40 mg/m2) were administered during the radiation therapy course.
RESULTS: A total of 106 patients were enrolled. Of these, 9 had major protocol violations and 2 did not receive treatment because of worsened general condition. Thus, 95 patients were evaluable. The median follow-up was 56 months. Of the 95 patients, 76 (80%) received 4 or 5 cycles of chemotherapy. Acute grade 3 leukopenia was observed in 20 of the patients (21%), and late grade 3 gastrointestinal toxicity was observed in 3%. The 2-year local control, progression-free survival, and overall survival rate for all patients were 96%, 78%, and 90%, respectively.
CONCLUSIONS: The results indicated that prophylactic extended-field concurrent chemoradiation therapy using weekly cisplatin is feasible and effective for patients with locally advanced cervical cancer in East and Southeast Asia.