Dosimetric effects of the Smit sleeve on high-dose-rate brachytherapy tandem and ovoids plans for patients with locally advanced cervical cancer.
Dosimetric effects of the Smit sleeve on high-dose-rate brachytherapy tandem and ovoids plans for patients with locally advanced cervical cancer. J Contemp Brachytherapy. 2019 Dec;11(6):584-588 Authors: Mehta S, Farnia B, de la Zerda A, Rahimi R, Wolfson A, Portelance L Abstract Purpose: Smit sleeves are used to facilitate insertion of the intrauterine tandem during brachytherapy for cervical cancer. When a tandem and ovoids system is used the base of the Smit sleeve displaces the ovoids distally. The dosimetric impact of this displacement is not known. Herein we performed a dosimetric analysis to quantify this impact on the integral dose and dose delivered to the organs at risk (OARs). Material and methods: Eleven high-dose-rate brachytherapy plans in which a Smit sleeve was used with a tandem and ovoids were reviewed. A second set of plans was generated modifying the position of the ovoids to simulate absence of the Smit sleeve. The high-risk clinical tumor volume (HR-CTV) dose coverage was maintained the same for both sets of plans by appropriately rescaling the dwell times of the simulated plan. The mean integral dose, D2cc to the OARs (bladder, bowel, sigmoid and rectum) and the ICRU rectum point dose were compared between the original and modified plans using a paired two-sample t-test. Results: Simulating removal of the Smit sleeve was associated with an average reduction in the mean integral dose of 6.1% (p
Conclusions: Our findings suggest that IMRT may represent a viable alternative in delivering the boost in patients diagnosed with gynaecological cancer not amenable to ICBRT. PMID: 32010217 [PubMed]
Conclusions: Smaller volume of bladder receive higher dose and larger volumes a lower dose with bladder distension, while dose is same for rectum, sigmoid and bowel. The applicators shift posteriorly when the bladder is distended.
Conclusions: The present study results show that all the dose parameters of HRCTV, bladder, and rectum with 60Co were comparable with those of 192Ir HDR source. The isodose distribution is more bulge out for 60Co in cranial-caudal direction compared to that of 192Ir. However, these differences can be reduced by treatment planning optimization techniques. The clinical plan evaluation in each slice and plane is necessary to explore the logistic and financial benefits of miniaturized 60Co source over 192Ir HDR source.
Conclusions: Dosimetric deviation for tumor and organs at risk is within acceptable limit while using CT image-based brachytherapy plan of the first fraction for treating successive fractions.
Conclusion: Conventional X-ray-based plans with moderate Point A doses deliver HRCTV D90 comparable to MRI-based plans in patients with no residual disease, and centrally placed residual disease, provided proper applicator placement and ideal geometry can be ensured. Soft-tissue image-based BT dose optimization ought to be considered in all patients with gross residual disease at the time of brachytherapy.
Conclusion: Optimal plans even with orthogonal radiographs may be generated by verifying the application based on the parameters mentioned in the present study and computed tomography-based plans could be utilized more effectively instead of doing automatic or manual optimization. Whereever orthogonal radiograph based or template based ICBT practices is performed this study may create a dataset to have an optimal treatment plan even without three-dimensional images.
Conclusion: Doses to both Manchester point A and ABS point A may be recorded during the transition period. However, ABS point A can be preferred over the Manchester point A as it conforms better with the desired dosimetric outcome and is found to be more static.
Conclusions: One of the benefits of applying DTDC constrained in IPSA plan is that, it removes local hot spots. It's another advantage is the reduction in rectum and bladder dose.
In conclusion, MRI provides goo d anatomical delineation of the relevant HR‐CTV and OAR, and performed better in the analyses of dose parameters compared with CT. At least one MR image is required to assess the tumour extension, with clinical findings and MRI information facilitating much more accurate CT‐based contouring.
CONCLUSION: IMRT is a highly conformal technique. Satisfactory target volume coverage was achieved with both techniques, with better sparing of OARs in the IMRT group. With this technique improvement, we expect better quality of life in cervical cancer patients with good prognosis. PMID: 31786871 [PubMed - in process]