Zuidhoek, E.N. and Kiekebosch, I.H. and Knottnerus, H. (2013) Hitting a moving target : Effect of Patient- and Tumor Characteristics on Intrafraction Motion and Set-up Accuracy for Stereotactic Lung Radiotherapy. thesis, Other studies (UMCG).
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Abstract
EFFECT OF PATIENT- AND TUMOR CHARACTERISTICS ON INTRAFRACTION MOTION AND SET-UP ACCURACY FOR STEREOTACTIC LUNG RADIOTHERAPY Kiekebosch, I.H.*, Zuidhoek, E.N.*, Knottnerus, H.*, van der Laan, L. †, de Vries, H. †, Schaake, W.*, Wiegman, E.M. † * University of applied sciences, Hanzehogeschool Groningen, the Netherlands † Department of Radiation Oncology, Isala Klinieken Zwolle, the Netherlands Purpose: To assess the influence of patient- and tumor characteristics (Body Mass Index (BMI), immobilization method, relative target motion, tumor size and tumor position) on set-up accuracy and intrafraction motion of lung stereotactic body radiation therapy (SBRT) patients. Methods and Materials: Set-up accuracy and intrafraction tumor motion was analyzed in 66 patients who underwent stereotactic lung radiotherapy. For each fraction, a localization cone-beam computed tomography (CBCT) scan (n=289) and verification CBCT scan (n=281) was acquired in order, to verify the immobilization. A CBCT scan was also performed at the end of the fraction (n=270), to assess the intrafraction motion. Data from the CBCT scans were recorded to determine systematic and random uncertainties, as well as planning target volume margins for all the patients. Data were further stratified and analyzed for the patient- and tumor characteristics. The significance of the characteristics on set-up accuracy and intra-fractional tumor motion was determined through the linear regression model. The relation between intra-fraction time and intra-fractional target movement was also analyzed. Results: Results of the entire research population show that a margin of 3,5 mm is needed. Tumors positioned above the carina need a margin up to 3,2 mm and tumors below the carina need a margin up to 3,7 mm. Patients with a BMI>26,2 need a margin up to 3,7 mm and for patients with a BMI<26,2 this is 3,2 mm. Three different immobilization methods were identified for subgroup analysis: evacuated cushion, PosirestTM and armrest. The evacuated cushion causes the least intra-fractional tumor motion. The BMI and the tumor size show a significant relation for the tumor motion in the set-up accuracy (p=0.023 and p=0.010). There is also a significant relation between the fractionation schedule and the intrafraction time (p=0,001). However, there is not a significant relation between the intrafraction time and the intrafraction motion (p=0,415). Conclusion: Set-up accuracy is in particular influenced by tumor size and BMI. There is not a significant relation between intrafraction motion and patient- and tumor characteristics. The evacuated cushion is the best way to immobilize patients during stereotactic lung radiotherapy. The differences between PTV margins for the relative target motion and tumor size are really small and apparently not clinically relevant. A larger margin (4 mm) is needed for patients with a high BMI and/or tumors below the carina.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | Drs. Wiegman, E.M. radiotherapeut-oncoloog Isala klinieken |
| Supervisor name: | Drs. Schaake, W. |
| Faculty: | Hanze University Groningen |
| Institute: | Academie voor Gezondheidsstudies |
| Awards/prices: | Nominatie Menzis prijs |
| Keywords: | intra-fractionele tumorbeweeglijkheid, patiëntkarakteristieken, tumorkarakteristieken, Stereotactische bestraling, Tumorbeweeglijkheid, Longkanker, Kanker |
| Date Deposited: | 25 Jun 2020 10:43 |
| Last Modified: | 25 Jun 2020 10:43 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/422 |
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