In this study, in vitro chemosensitivity testing was conducted on primary cultured breast cancer cells from 96 patients with breast cancer, and the results showed that the cells from a few patients with primary breast cancer developed multidrug resistance (MDR) prior to the first chemotherapy exposure. All the cells from the recurrent cancer patients had MDR. The findings suggested that patients having MDR would benefit from high-dose chemotherapy (HDC) regimens. In vitro chemosensitivity screening, which was aimed at improving the therapeutic efficacy and minimizing side effects, helps in choosing individualized treatment for breast cancer.
Antineoplastic Agents/*pharmacology ; Breast Neoplasms/*drug therapy ; Breast Neoplasms/pathology ; Drug Resistance, Multiple ; Drug Resistance, Neoplasm ; Drug Screening Assays, Antitumor/*methods ; Neoplasm Recurrence, Local/*drug therapy ; Tumor Cells, Cultured

Objective To verify the absorbed dose and two-dimensional dosimetry delivered by MLC-shaped IMRT photon beams using thermoluminescent dosimeters (TLDs) and radiochromic films.Methods Different types of medical linear accelerators at 7 third-grade first-class hospitals in Hubei were selected for this audit study.Besides TLDs and films,a small polystyrene phantom measuring 15 cm × 15 cm × 15 cm,supplied by the International Atomic Energy Agency (IAEA),was also used.The TPS dose calculation were performed with 6 MV X-ray beam and by delivering 6 Gy dose to the TLDs or films at 10 cm depth for 5 cm × 5 cm field size at 90 cm SSD.After irradiation,comparations were conducted of dose derivations between TPS-calculated values and TLD-or film-measured values.The two-dimensional dosimetry audit was carried out by using 30 cm × 30 cm homogeneous solid phantoms in which a 25 cm × 25 cm film was located at 5 cm depth.A single-filed profile generated by TPS was delivered to the film,and the film was measured.And then,two-dimensional dose distribution was analyzed using the film analysis system.Results The results suggested that the relative deviations of TLD and film to TPS dose was-8.5％ and-1.9％ for accelerator 1,5.4％ and 0.5％ for accelerator 7,respectively,whereas those for other accelerators were within ± 5％.The passing rates for two-dimensional dose distribution at all accelerators were all higher than 90％.Conclusions TLD and film quality audit for IMRT can be applied for a wide range of application in view of its simplicity,reliability and postal convenience.

BACKGROUND: Current oral restoration membranes are expensive with a potential risk of zoonotic virus, so new membranes are in need. OBJECTIVE: To prepare fish skin acellular dermal matrix and evaluate its efficiency of decellularization, biomechanical properties and biocompatibility, in order to explore its feasibility as an oral restoration membrane. METHODS: The skin of Astroconger Myriaster was harvested to prepare acellular dermal matrix by decellularization via a combination of physical method and chemical and biological reagents. The micromorphology of the material was observed under scanning electron microscope. Tissue composition was analyzed by hematoxylin-eosin, Masson and PAS staining. The DNA content was detected using a kit. The biocompatibility was evaluated through cytotoxicity and animal skin stimulation tests. RESULTS AND CONCLUSION: The prepared acellular dermal matrix: (1) was white or light yellow, with strength and toughness; (2) exhibited a double-layered structure composed of a dense layer and a loose layer; (3) was mostly composed of collagen without PAS positive substance, showing good decellularization; (4) had a significantly lower DNA content than natural fish skin and commercial oral restoration membrane; and (5) possessed good biocompatibility, with very low cytotoxicity and no stimulation to the animal skin. Therefore, the prepared acellular dermal matrix of fish skin shows a potential in the preparation of oral guided tissue regeneration membrane.

In this study, in vitro chemosensitivity testing was conducted on primary cultured breast cancer cells from 96 patients with breast cancer, and the results showed that the cells from a few patients with primary breast cancer developed multidrug resistance (MDR) prior to the first chemotherapy exposure. All the cells from the recurrent cancer patients had MDR. The findings suggested that patients having MDR would benefit from high-dose chemotherapy (HDC) regimens. In vitro chemosensitivity screening, which was aimed at improving the therapeutic efficacy and minimizing side effects, helps in choosing individualized treatment for breast cancer.

Objective To verify the leaf positioning accuracy of multi-leaf collimator (MLC) in intensity modulated radiation therapy (IMRT) by using radiochromic films to provide references for IMRT quality control.Methods Medical linear accelerators of different designs,owned by 7 first-class hospitals at grade-3 in Hubei,were selected for this verification study.Five strip picket fence pattern was created by treatment planning system (TPS).Each strip was 0.6 cm wide with a 3 cm strip separation.MLC leaf positions,positioning bias and opening widths were then measured with EBT2 radiochromic films.Results According to IAEA standards,the film-measured and TPS planned MLC leaf position difference was ±0.5 mm.The difference of MCL strip position of No.5 and No.7 accelerator was 0.7 and-1.0 mm,respectively,not in line with the IAEA standards.The difference of film-measured MLC leaf position between each pairs and all pairs of leaves of 7 accelerators were all within ± 0.5 mm,in line with the IAEA requirements.As required by IAEA,the difference of opening width of MLC leave of each pair relative to the averaged widths of all pairs should be within ±0.75 mm.The filem-measured values from 7 accelerators ranged from-0.6 to 0.5 mm,all in line with the IAEA standards.Standard deviation of opening width of all leaves were required to be within 0.3 mm.The measured values from 7 accelerators ranged from 0.1 to 0.2 mm,in line with the IAEA standard.Conclusions The use of EBT2 radiochromic films to verify MLC leaf positioning accuracy is an important means of quality control owing to its simplicity and high measurement accuracy.It is recommended for verification use at a large scale.

Objective To assess the medical radiation exposure frequency and find out the main factors related to the collective dose derived from X-ray diagnosis procedures. Methods A survey of 3 178 hospitals was conducted to collect the basic information such as types of medical radiation, allocation of radiological diagnosis and treatment devices, the frequency of radiologic examinations, etc. By using a stratified sampling method，36 hospital were selected and more specific details, including 26 types of diagnostic radiologic examinations, were collected to estimate the collective dose to the population in Hubei, combining with the previous literature. Results A total number of 6 843 radiological diagnosis and treatment devices were covered and 33 771 855 medical radiologic procedures were counted in this survey. The result showed a annual frequency of 569.79 examinations per 1 000 population for all types of procedures. A large variation was revealed among different areas and the highest area was with a 4-fold frequency of the lowest area. Although tertiary hospitals accounted for 4.40% of the total hospitals, 48.42% procedures were carried out in them. The collective effective dose from X-ray diagnosis in Hubei was 65 399.55man·Sv, and the average annual effective dose was 1.10mSv, while contribution from CT scans accounted for 86.90% of the dose. Conclusion The frequency of medical radiologic procedures presented a consistent increase in Hubei province, with a uneven development among hospitals from urban and rural areas, or from different regions, or from different levels. Among all types of X-ray examinations, CT scan frequency had the fastest growth rate and accounted for the major annual collective effective dose. In order to reduce the health risk from medical radiologic exposure, CT scan need to be applied more properly and the radiation dose per single CT scan need to be limited to a reasonable level.

Objective: To study a method to measure the doses to planned target volume (PTV) and organ at risk (OAR) and 2D dose distribution in IMRT by using TLD and radiochromic film for a verification purpose. Methods: Totally 7 different types of medical linear accelerators were selected from seven hospitals in Hubei province. A polystyrene phantom provided by IAEA was CT scanned and then the scanned images were returned to the Treatment Planning System (TPS) for determining the prescribed doses to PTS and OAR and the corresponding MU. After the phantom was irradiated with 6 MV X-ray, the TLDs and films were transmitted to the secondary standard dosimetry laboratory of China CDC for measurement and estimation. Results: The IAEA required the relative deviations between TLD-measured and TPS-planned doses to OAR and PTV be within ±7.0%. For PTV, the measured-to-planned deviation values for 7 accelerator were within -5.4% to 6.5%, all consistent with the IAEA requirements. For OAR, the values for 5 accelerators were within -2.2% to 6.7%, not consistent the requirements, whereas the values for the other 2 were -8.6% and 8.2% respectively, beyond the required values. The IAEA required that the 2D dose distribution 3 mm/3% pass rate be higher than 90%. The measured values for 7 accelerators were in the range of 90.3%-98.9%, all consistent with the requirements. Conclusions It is feasible scientifically and easy to operate in practice for using TLD and film to carry out dose verification in IMRT. It would be advisable to apply this method to quality verification in IMRT in medical institutions to the extent possible.