RESUMO
The primary purpose of the study is to evaluate the implementation of Helical TomoTherapy (HT) for eligible stereotactic radiosurgery/stereotactic body radiotherapy/stereotactic ablative radiotherapy (SRS/SBRT/SABR) cases using TomoEDGE option. The study focuses on reduction of treatment time without compromise in plan quality using TomoEDGE. It is a mode in HT that uses a dynamic opening of the jaws during treatment delivery to reduce the dose penumbra which otherwise is not possible with fixed jaws option. Eligible SRS/SBRT/SABR cases of lung, liver, and spine were used in this study. All planning parameters such as dose prescription to target and critical organs, pitch, and modulation factor were same in all the plans of the same patient with modifications in the field width and jaw mode. First set of plans with 2.5 cm width and second set of plans with 5 cm width were done in dynamic TomoEDGE mode. Third set of plans created with 5 cm width fixed jaw mode and fourth set of plans with 2.5 cm fixed jaw mode for comparison purpose were done. Our observations achieved that a significant milestone with reduction of up to 34.3% in treatment time of liver cases, 35.2% in lung cases, and 28.7% in spine cases was observed using dynamic TomoEDGE mode with 5 cm width, while no significant variation in the planning results compared with plans using 2.5 cm dynamic TomoEDGE option. TomoEDGE is an efficient and useful mode in TomoTherapy to reduce the treatment time with bigger field width in SRS/SBRT/SABR cases without significant changes in the plan quality.
RESUMO
TomoTherapy® is a modern radiation treatment technique in which intensity-modulated radiation therapy (IMRT) is delivered in helical fashion. A two-dimensional (2D) array which has been existing for IMRT patient-specific quality assurance (PSQA) verifications for many years is I'MatriXX. Our objectives were to validate this I'MatriXX and to evaluate it for different patient sites and fractionation schedules of TomoTherapy treatment. Twenty-five plans were created with virtual target for different possible pitch values and field widths for validation. Gamma index criteria of 3%/2% dose differences and 3/2 mm distance to agreement were used. QA plans of 26 different treatment sites and different fractionation schedules were used. Results indicated that the matrix response is independent of field width, pitch, and modulation factor of TomoTherapy with 3%, 3 mm criteria. High passing rate ranging from 99.7% to 90.7% was observed for selected patient plans. We found that I'MatriXX 2D array can be utilized for easy and quick TomoTherapy PSQA.
RESUMO
Matrix metalloproteinases (MMPs) play an important role in breast cancer tumor invasion and progression. MMP-9 is a member of the MMP family and is also known as Gelatinase B or type IV collagenases (92 kDa) and possesses proteolytic activity against type IV collagen, a major component of the basement membrane. Our study aims to examine the association of Gelatinase B (-1562C > T) promoter polymorphism with breast cancer invasion and progression. The study involves 200 breast cancer patients and age-matched 191 healthy controls. The SNP-1562C > T (rs3918242) in MMP-9 promoter region was examined by allele-specific polymerase chain reaction and gel electrophoresis. The genotypes were determined and compared between patients and controls, and the influence of the polymorphism on clinicopathological data was analyzed. The T allele of the -1562C > T MMP-9 polymorphism was detected more frequently in breast cancer patients than controls (p < 0.001). Our results suggest the clinical importance of MMP-9 gene polymorphism (-1562C > T) in breast cancer patients. The study may also help in identifying individuals at risk of developing breast cancer.