Evaluation of interfraction patient setup errors for image-guided prostate and head-and-neck radiotherapy using kilovoltage cone beam and megavoltage fan beam computed tomography. Issue 4 (30th May 2013)

• Record Type: Journal Article
• Authors: Qi, X. Sharon; Wu, Sutan; Newman, Francis; Li, X. Allen; Hu, Angie Y.
• Is Part Of: Journal of radiotherapy in practice. Volume 12:Issue 4(2013)
• Page Start: 334
• Page End: 343
• Publication Date: 2013-05-30
• Subjects: image-guided radiotherapy (IGRT), -- KV cone beam CT (KVCBCT), -- MV fan beam CT (MVFBCT), -- head-and-neck cancer, -- prostate cancer; Radiotherapy -- Periodicals; 615.842005
• DOI: 10.1017/S1460396912000337
• Languages: English
• ISSNs: 1460-3969

Abstract

Abstract: Purpose: To analyse interfraction setup using two different image guidance modalities for prostate and head-and-neck (H&N) cancer treatment. Materials and methods: Seventy-two prostate and 60 H&N cancer patients, imaged with kilovoltage cone beam computed tomography (KVCBCT) or megavoltage fan beam computed tomography (MVFBCT), were studied retrospectively. The daily displacements in mediolateral (ML), craniocaudal (CC) and anteroposterior (AP) dimensions were investigated. The setup errors were calculated to determine the clinical target volume to planning target volume (CTV-to-PTV) margins. Results: Based on 1, 606 KVCBCT and 2, 054 MVFBCT scans, average interfraction shifts in ML, CC and AP direction for H&N cases were 0·5 ± 1·5, −0·3 ± 2·0, 0·3 ± 1·7 mm using KVCBCT, 0·2 ± 1·9, −0·2 ± 2·4 and 0·0 ± 1·7 mm using MVFBCT. For prostate cases, average interfraction displacements were −0·3 ± 3·9, 0·2 ± 2·4, 0·4 ± 3·8 mm for MVFBCT and −0·2 ± 2·7, −0·6 ± 2·9, −0·5 ± 3·4 mm for KVCBCT. The calculated CTV-to-PTV margins, if determined by image-guided radiotherapy (IGRT) data, were 5·6 mm (H&N) and 7·8 mm (prostate) for MVFBCT, compared with 4·8 mm and 7·2 mm for KVCBCT. We observed no statistically significant difference in daily repositioning using KVCBCT and MVFBCT in early, middle and late stages of the treatment course. Conclusion: In the absence of IGRT, the CTV-to-PTV margin determined using IGRT data, may be varied for different imaging modalities for prostate and H&N irradiation.