Table 5 Comparison of the technique, the factors examined and the cutoff values for our study and other studies

Ferdinand et al. [21]

Dosimetric results of free breathing (FB) vs. deep inspiration breath hold (DIBH) techniques are compared

(1) Heart volume (HV)

(2) Lung volume (LV)

(3) Heart chest wall length (HCWL)

(4) Heart height (HH)

(5) Chest separation (CS)

(6) Chest depth (CD)

(7) Heart chest wall distance (HCWD)

(8) Maximum heart depth (MHD)

(9) Heart volume in field (HVIF)

(10) Lung ortogonal distance (LOD)

(11) Central lung distance (CLD)

Maksimum heart depth = 7 mm

ΔHeart volume in field = 6 cc

Czeremszyn´ska et al. [22]

Dosimetric results of FB vs. DIBH techniques are compared

(1) Body mass index (BMI)

(2) Age

(3) Planning target volume (PTV)

(4) Cardiac contact distance (CCD)

(5) Lung volume at FB

For ΔMHD, ΔV20 Heart and ΔLADmax

For 20% improvement, in order;

In the BMİ 22.3, 22.3, 24.8

In the CCD 2.9, 2.9, 3.8 cm

In the PTV volume 577, 445 cc

For 50% improvement, in order;

In the BMİ 27.6, 22.3, 26.0

In the CCD 5.7, 2.9, 3.0 cm

In the PTV volume 703, 445 cc

Taylor et al. [23]

To assess the value of MHD in predicting the dose and biologically effective dose (BED) to the heart and the left anterior descending (LAD)

(1) Mean dose and BED to the heart,

(2) Mean dose and BED to the LAD coronary artery,

(3) MHD,

(4) Position of the CT slice showing the maximum area of the irradiated heart relative to the mid-plane slice, and

(5) Sternal and contralateral breast thickness (measures of body fat)

Every 1-cm increase in MHD

Tanna et al. [24]

Comparing four methods of patient selection for FB or DIBH

(1) FB scan on all patients, selecting DIBH technique for mean heart dose ≥ 3 Gy;

(2) Selective DIBH for those with MHD on FB scan ≥ 1 cm;

(3) Use of an ‘upfront selection process’ using tumor bed position as initial selection and measurement of MHD on those not selected upfront;

(4) DIBH on all

‘Upfront selection process’

MHD

Wang et al. [25]

The automated treatment planning process is investigated

The heart volume within the radiation field (heart V50 > 10 cm3)

Our study

Before starting the planning, factors that will predict the choice of technique are investigated

(1) PTV volume

(2) Left lung volume

(3) Heart volume

(4) Left lung/heart volume ratio

(5) Heart/PTV volume ratio

(6) Left lung/PTV volume ratio

Lung/heart volume ratio = 1.92

Left lung volume = 1154 for BCS patients and 1208 cc for mastectomy patients