Impact of Different CT Slice Thickness on Clinical Target Volume for 3D Conformal Radiation Therapy

Prabhakar, R; Ganesh, T; Rath, Goura Kishor; Julka, Pramod Kumar; Sridhar, P.S.; Joshi, Rajesh; Thulkar, Sanjay

doi:10.1016/j.meddos.2007.09.002

Cited by 16 publications

(18 citation statements)

References 18 publications

(15 reference statements)

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“…Those studies were also limited to small changes in investigated slice thickness (Ebert et al 2010, Kirisits et al 2007) or mainly concerned large structures (Weinberg et al 2004). It has been demonstrated that coarse image inter-slice spacing has larger effects on small volumes (<100–200 cm 3 ) than on large volumes, with respect to structure volume and dose (Ebert et al 2010, Prabhakar et al 2009, Weinberg et al 2004). The rectum and rectal wall volumes for the originally acquired slice thicknesses in the study presented here were small, on average 93 to 94 cm 3 and 45 to 50 cm 3 , respectively.…”

Section: Discussionmentioning

confidence: 99%

“…Several sources of uncertainty when pooling data exist and among these, coarse image slice thickness, as used in earlier treatment approaches, is one example. The impact of varying image slice thickness on calculated volumes, as well as on calculated doses, has to some extent been investigated using dose-volume histograms (DVHs) (Butler et al 2000, Ebert et al 2010, Kirisits et al 2007, Prabhakar et al 2009, Somigliana et al 1996, Weinberg et al 2004). Coarse image slice thickness typically introduces larger differences in calculated volumes for small, as compared to large, structures (Ebert et al 2010, Kirisits et al 2007, Prabhakar et al 2009, Weinberg et al 2004).…”

Section: Introductionmentioning

confidence: 99%

“…However, for calculated doses, differences are typically lower than ±3.5–5% (cf. accuracy required for the absorbed dose to the target) (Ebert et al 2010, Kirisits et al 2007, Prabhakar et al 2009, Weinberg et al 2004). Although it is assumed that dose differences of such orders are unlikely to impact dose-response relationships (Butler et al 2000, Ebert et al 2010), it has, to the best of our knowledge, still not been investigated.…”

Section: Introductionmentioning

confidence: 99%

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Influence of image slice thickness on rectal dose–response relationships following radiotherapy of prostate cancer

Olsson¹,

Thor²,

Liu³

et al. 2014

Phys. Med. Biol.

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When pooling retrospective data from different cohorts, slice thicknesses of acquired computed tomography (CT) images used for treatment planning may vary between cohorts. It is, however, not known if varying slice thickness influences derived dose-response relationships. We investigated this for rectal bleeding using dose-volume histograms (DVHs) of the rectum and rectal wall for dose distributions superimposed on images with varying CT slice thicknesses. We used dose and endpoint data from two prostate cancer cohorts treated with 3D-CRT to either 74 Gy (N=159) or 78 Gy (N=159) @ 2 Gy per fraction. The rectum was defined as the whole organ with content, and the morbidity cut-off was Grade ≥2 late rectal bleeding. Rectal walls were defined as 3-mm inner margins added to the rectum. DVHs for simulated slice thicknesses from 3 to 13 mm were compared to DVHs for the originally acquired slice thicknesses at 3 and 5 mm. Volumes, mean, and maximum doses were assessed from the DVHs, and gEUD values were calculated. For each organ and each of the simulated slice thicknesses, we performed predictive modeling of late rectal bleeding using the Lyman-Kutcher-Burman (LKB) model. For the most coarse slice thickness, rectal volumes increased (≤18%), whereas maximum and mean doses decreased (≤0.8 Gy and ≤4.2 Gy, respectively). For all a values, the gEUD for the simulated DVHs were ≤1.9 Gy different than the gEUD for the original DVHs. The best-fitting LKB model parameter values with 95% CIs were consistent between all DVHs. In conclusion, we found that the investigated slice thickness variations had minimal impact on rectal dose-response estimations. From the perspective of predictive modeling, our results suggest that variations within 10 mm in slice thickness between cohorts are unlikely to be a limiting factor when pooling multi-institutional rectal dose data that include slice thickness variations within this range.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of image slice thickness on rectal dose–response relationships following radiotherapy of prostate cancer

Olsson¹,

Thor²,

Liu³

et al. 2014

Phys. Med. Biol.

View full text Add to dashboard Cite

show abstract

“…The information provided by the dose volume histogram is based on the definition of tumor and critical structures, and also on the accuracy of the calculation algorithms. The target volume definition is influenced by several parameters such as imaging modality, [9,10] interobserver variability, [11][12][13] patient movement/setup errors, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] resolution limitation of the scanner [17] and contouring system. [6] In this study, we have assessed the variation of tumor volume between different treatment planning systems and also compared the differences in generating PTV from CTV with different planning systems.…”

Section: Discussionmentioning

confidence: 99%

“…All the patients underwent computed tomography (CT) scanning on Philips TM Brilliance Big Bore 16 slice CT scanner with a slice thickness of 3 mm. [7] The CT datasets were transferred to the Eclipse TM treatment planning system (ver. 6.5) which is used as a reference contouring station for volume comparison.…”

Section: Methodsmentioning

confidence: 99%