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High dose rate (HDR) brachytherapy treatment planning usually involves optimization methods to deliver uniform dose to the target volume and minimize dose to the healthy tissues. Four optimizations were used to evaluate the high-risk clinical target volume (HRCTV) coverage and organ at risk (OAR). Dose-volume histogram (DVH) and dosimetric parameters were analyzed and evaluated. Better coverage was achieved with PGO (mean CI = 0.95), but there were no significant mean CI differences than GrO (p = 0.03322). Mean EQD2 doses to HRCTV (D90) were also superior for PGO with no significant mean EQD2 doses than GrO (p = 0.9410). The mean EQD2 doses to bladder, rectum, and sigmoid were significantly higher for NO plan than PO, GrO, and PGO. PO significantly reduced the mean EQD2 doses to bladder, rectum, and sigmoid but compromising the conformity index to HRCTV. PGO was superior in conformity index (CI) and mean EQD2 doses to HRCTV compared with the GrO plan but not statistically significant. The mean EQD2 doses to the rectum by PGO plan slightly exceeded the limit from ABS recommendation (mean EQD2 dose = 78.08 Gy EQD2). However, PGO can shorten the treatment planning process without compromising the CI and keeping the OARs dose below the tolerance limit.

The efficacy of recombinant human thyroid stimulating hormone (rhTSH) and thyroid hormone withdrawal (THW) in estimating the whole body radioactive clearance was done by measuring the exter...

Radiotherapy is an important treatment modality for cancer treatment, particularly for locally advanced tumours and it is known to induce cell death in tumours. Radiotherapy is limited by the total dose that can be prescribed without damaging normal tissueThe main aims of radiotherapy to optimally eradicate tumours while sparing the normal tissue could be achieved with the combination treatment using natural products based medicinal plants. Oroxylum indicum (OI) is a Malaysian consumable plant with a variety of health attributes that contains useful active biocompound that serves as anticancer agent. In this study, the potentials of OI extracts to increase cells radiosensitivity towards radiotherapy were investigated. Initially, the cytotoxic effects of OI extracts were determined in-vitro using HeLa cells. The cells with non-toxic concentration of OI extracts were irradiated with 6 MV and 10 MV photon beams. The cell survivals after irradiation were then evaluated using PrestoBlue assay. The OI extracts with maximum concentration of 0.01 mg/ml are found nontoxic to HeLa cells. The combination of OI extracts and irradiation are found to reduce the cells survival which indicates radiosensitization effects. The sensitization enhancement ratio (SER) calculated indicate higher radiosensization observed for 6 MV photon beams compare to 10 MV photon beams. SER also increased at higher OI concentration. In conclusion, the OI extracts are found to induce radiosensitization in HeLa cancer cells when irradiated with megavoltage photon beams. This study indicates the potential of plant based natural product to be applied as radiosensitizer to increase the therapeutic efficiency in radiation therapy of cancer.

Background Nanomaterials have been applied as radiosensitizer in an effort to improve the effectiveness of radiotherapy in killing cancer cells while simultaneously sparing the healthy normal tissue. Increase in radiotoxicity to the cancerous region might also influence the non-targeted cells through radiation-induced bystander effect (RIBE) mechanism. In this study, we implemented Bi2O3 NPs as radiosensitizer in combination with megavoltage radiotherapy and probe into the RIBE consequences in the non-targeted cells. Aim To investigate the effects of bismuth oxide nanoparticles (Bi2O3 NPs) on RIBE triggered in MCF-7 and hFOB 1.19 after irradiation with 10 MV clinical photon beam. Materials and methods The MCF-7 (human breast cancer) and hFOB 1.19 (human fetal osteoblast) cell lines were incubated with and without Bi2O3 NPs prior to irradiation. The treated cells were irradiated with radiation doses of 0 to 12 Gy using 10 MV photon beam in a single exposure. The irradiated-cell conditioned medium (ICCM) were collected from the targeted cells and transferred into the non-targeted cells. Reactive oxygen species (ROS), cell viability and colony forming assay was employed to evaluate the effect. Results The present study demonstrated that the MCF-7 and hFOB 1.19 bystander cells are able to maintain their cell viability for more than 80% after 48 h incubation with ICCM treated with Bi2O3 NPs at 2 Gy radiation dose. The percentage of cell survival fraction of hFOB 1.19 cells which received ICCM with Bi2O3 NPs decreased to 86.8%, in contrast to MCF-7 bystander cells which show an increment in their cells survival after treatment with Bi2O3 NPs. Our results show that the ROS level was increased in the bystander cells, but the addition of Bi2O3 NPs did not significantly increase the ROS level. Conclusions The application of nanoparticles for radiosensitization during radiotherapy must also considered the RIBE responses in the non-irradiated cells. These findings provide evidence that the use Bi2O3 NPs as radiosensitizer in radiotherapy is safe and do not significantly increase the RIBE responses in non-targeted cells.