Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Sep;45(3):915-924.
doi: 10.1007/s13246-022-01162-y. Epub 2022 Aug 4.

Clinical implementation of kVCT-guided tomotherapy with ClearRT

Bin Yang  1 , Hui Geng  2 , Tien Yee Amy Chang  3 , Mei Yan Tse  2 , Wai Wang Lam  2 , Chen-Yu Huang  2 , Tungho Wu  4 , Ka Ki Lau  2 , Kin Yin Cheung  2 , George Chiu  5 , Siu Ki Yu  2
Affiliations

Clinical implementation of kVCT-guided tomotherapy with ClearRT

Bin Yang et al. Phys Eng Sci Med. 2022 Sep.

Abstract

A helical fan-beam kilovoltage computed tomography (kVCT) was recently introduced into Tomotherapy units. This study aims to share the initial experience of kVCT in clinical workflow, compare its performance with that of the existing megavoltage computed tomography (MVCT), and explore its potential in adaptive planning. We retrospectively enrolled 23 patients who underwent both MVCT and kVCT scans. The clinical performance data regarding image acquisition time, nominal dose length product (DLP), registration time and registration corrections were extracted and compared. Image quality was scored by six experienced radiation therapists and quantified based on phantom measurements. CT number stability and the implementation of adaptive radiotherapy were dosimetrically evaluated by performing the dose recalculation on kVCT. Compared to MVCT, kVCT significantly reduced DLP (except the highest kVp protocol), image acquisition and registration time. KVCT obtained higher scores than MVCT on all criteria except artifacts. Phantom measurements also revealed a better image performance characterization of kVCT except for image uniformity. The CT number variation could lead to a dose difference of 0.5% for D95% of target and Dmean of organ-at-risk. For the treatment planning with kVCT, a systematic dose difference (> 1%) in PTV dose metrics was observed at regions with large longitudinal density discontinuities compared to the reference plans. The new kVCT imaging provides enhanced soft-tissue visualization. The improved efficiency with kVCT-guided treatment will allow more patients to be treated each day. In most cases, the dose calculation accuracy of kVCT images is acceptable except for regions with severe artifacts.

Keywords: ClearRT; Dosimetric evaluation; Image quality; Radixact; Tomotherapy; kVCT.

PubMed Disclaimer

References

    1. Alongi F, Fodor A, Maggio A, Cozzarini C, Fiorino C, Broggi S, Alongi P, Calandrino R, Muzio ND (2011) Megavoltage CT images of helical tomotherapy unit for radiation treatment simulation: impact on feasibility of treatment planning in a prostate cancer patient with bilateral femoral prostheses. Tumori 97(2):221–224. https://doi.org/10.1700/667.7787 - DOI - PubMed
    1. Aubin M, Morin O, Chen J, Gillis A, Pickett B, Aubry JF, Akazawa C, Speight J, Roach 3 M, Pouliot J (2006) The use of megavoltage cone-beam CT to complement CT for target definition in pelvic radiotherapy in the presence of hip replacement. Br J Radiol 79(947):918–921. https://doi.org/10.1259/bjr/19559792
    1. De Marco P, Abdi Osman I, Castellini F, Ricotti R, Leonardi MC, Miglietta E, Cambria R, Origgi D, Jereczek-Fossa BA, Garibaldi C, Cattani F (2019) Image quality and dose evaluation of MVCT TomoTherapy acquisitions: a phantom study. Phys Med 57:200–206. https://doi.org/10.1016/j.ejmp.2019.01.009 - DOI - PubMed
    1. Kilby W, Sage J, Rabett V (2002) Tolerance levels for quality assurance of electron density values generated from CT in radiotherapy treatment planning. Phys Med Biol 47(9):1485–1492. https://doi.org/10.1088/0031-9155/47/9/304 - DOI - PubMed
    1. Langen KM, Papanikolaou N, Balog J, Crilly R, Followill D, Goddu SM, Grant 3 W, Olivera G, Ramsey CR, Shi C, Group AT (2010) QA for helical tomotherapy: report of the AAPM Task Group 148. Med Phys 37(9):4817–4853. https://doi.org/10.1118/1.3462971

MeSH terms