The receiver operating characteristic curves (ROC) of the five normal tissue complication probability models for symptomatic radiation pneumonitis in breast cancer patients treated with hybrid IMRT.

<p>Five factors: IV20, energy, age, body mass index (BMI) and T stage.</p

Candidate predictive factors initially.

<p><i>Abbreviation</i>: BMI: body mass index; SCF: Irradiated to supraclavicular fossa; IMN: Irradiated to internal mammary lymph nodes</p><p>MLD: mean dose to the ipsilateral lung; IV5-IV50: ipsilateral lung volume received 5-50Gy (%); p-valve: univariate logistic test; AIV5-AIV50: absolute ipsilateral lung volume received 5-50Gy (cc); p-valve: univariate logistic test</p><p>^#0 = Left, 1 = Right</p><p>*0 = No, 1 = Yes</p><p>^ѱ0 = PM (partial mastectomy), 1 = MRM (modified radical mastectomy)</p><p>^&0 = 6MV, 1 = 10MV, 2 = 6+10MV; T stage: 0 = T0, T1 (T1a, T1b, T1c, T1m, T1s), 1 = T2, 2 = T3, T4 (T4a, T4b)</p><p>N stage: 0 = N0, 1 = N1 (N1, N1a), 2 = N2 (N2, N2a), N3 (N3, N3a, N3b)</p><p>Lung (d): maximum Lung depth from chest wall to tangential line between extreme points of PTV in the section of nipple on CT image; Total (d): maximum depth from skin to tangential line between extreme points of PTV in the section of nipple on CT image</p><p>Candidate predictive factors initially.</p

Predictive factors correlation ranked by LASSO.

<p><i>Abbreviation</i>: LASSO: least absolute shrinkage and selection operator; BMI: body mass index</p><p>SCF: Irradiated to supraclavicular fossa; IMN: Irradiated to internal mammary lymph nodes; MLD: mean dose to the ipsilateral lung; IV5-IV50: ipsilateral lung volume received 5-50Gy (%); AIV5-AIV50: absolute ipsilateral lung volume received 5-50Gy (cc); Definition of risk factors: Same as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131736#pone.0131736.t002" target="_blank">Table 2</a>.</p><p>Lung (d): maximum Lung depth from chest wall to tangential line between extreme points of PTV in the section of nipple on CT image; Total (d): maximum depth from skin to tangential line between extreme points of PTV in the section of nipple on CT image</p><p>Predictive factors correlation ranked by LASSO.</p

Characteristics of patients.

<p><i>Abbreviation</i>: Group 0: Without symptomatic radiation pneumonitis; Group 1: Symptomatic radiation pneumonitis</p><p>BMI: body mass index; SCF: Irradiation to supraclavicular fossa; IMN: Irradiation to internal mammary lymph nodes; PM: partial mastectomy; MPM: modified radical mastectomy; SRP: Symptomatic radiation pneumonitis; Lung (d): maximum Lung depth from chest wall to tangential line between extreme points of PTV in the section of nipple on CT image</p><p>Total (d): maximum depth from skin to tangential line between extreme points of PTV in the section of nipple on CT image</p><p>Characteristics of patients.</p

Multivariate logistic regression coefficients and odds ratios for the NTCP model.

<p><i>Abbreviation</i>: IV20: the ipsilateral lung volumes receiving doses of 20Gy; BMI: body mass index; CI: confidence interval</p><p>^&0 = 6MV, 1 = 10MV, 2 = 6+10MV; T stage: 0 = T0, T1 (T1a, T1b, T1c, T1m, T1s), 1 = T2, 2 = T3, T4 (T4a, T4b)</p><p>Multivariate logistic regression coefficients and odds ratios for the NTCP model.</p

(a) A sample breast cancer treatment plan, (b) diagnosed with RP at 3 months after RT, (c) diagnosed with RP image fused with the original isodose curves.

<p><i>Abbreviation</i>: RP: radiation pneumonitis; RT: radiotherapy.</p

System performance evaluation.

<p><i>Abbreviation</i>: AUC: Area under the receiver operating characteristic curve; HL: Hosmer–Lemeshow test; the first five predictive factors were IV20, energy, age, BMI, and T stage.</p><p>System performance evaluation.</p

The univariate logistic normal tissue complication probability models with (a) IV20 and (b) AIV20 for symptomatic radiation pneumonitis in breast cancer patients treated with hybrid IMRT.

<p><i>Abbreviation</i>: IV20: ipsilateral lung volume received >20Gy (%); AIV20: absolute ipsilateral lung volume received >20Gy (cc); IMRT: intensity modulated radiotherapy.</p

Analyses of dosimetric parameters for patients without and with grade 2+ radiation dermatitis.

<p>Analyses of dosimetric parameters for patients without and with grade 2+ radiation dermatitis.</p

Comparison of the mean skin dose-volume histograms of patients with and without radiation dermatitis (RD) grade 2⁺ toxicity.

<p>Blue line = RD grade ≤ 1; red line = RD grade ≥ 2. V_X is the irradiation dose to the skin (5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 52 Gy).</p