Between April 2021- May 2022, 41 patients and 51 lesions were treated in a total of 171 fractions. Twenty-one patients were female, and 20 were male. The median age was 60 (32–82). The median Karnosky performance status was 90 (70–100). Patient characteristics are summarised in Table 1. The maximum lesion diameter was 24,5 mm (4–56 mm).
Table 1
| Primary site | Colorectal | 18 |
| Breast | 8 |
| Lung | 2 |
| Uterus | 2 |
| Pancreatic | 2 |
| Others | 9 |
| Language | Native | 34 |
| Non-Native | 7 |
| Factors that can affect breathing- lung capacity | Yes | 18 |
| No | 23 |
| Previous BH history | Yes | 9 |
| No | 32 |
| Lesion Number | 1 | 34 |
| 2 | 5 |
| 3 | 1 |
| 4 | 1 |
Patients were treated in 3 or 5 fractions. The median dose was 46,6 Gy (24–54 Gy). The treatment details are summarized in Table 2.
Table 2
| Fraction number | 3 | 17 |
| | 5 | 24 |
| Field (Arc) number | 2 | 39 |
| | 3 | 2 |
| MV | 6 | 37 |
| 10 | 4 |
| PTV volume | Median: 59.1 cm3 | Range (9.5 -293.5 cm3 |
| GTV volume | Median: 21.7 cm3 | Range (1.3-146.8 cm3) |
| Monitor Unit | Median: 3081.6 | Range (1812–5370) |
The PROMs are described in Table 3. Previous training before CT simulation and treatment was beneficial. The equipment used in the BH and the commands given by the technician was understandable. Holding breath is tolerable during CT simulation and treatment period. The treatment duration is not long. Patients have little stress during CT scans and little worry about taking an active role in the treatment and CT scan (Table 3).
Table 3
Patient-reported outcome (PRO) questionnaire.
| First questionnaire (Before planning CT) | 1–4 scale |
| 1. Did you find the training you received before the breath-hold procedure helpful? | 4 |
| 2. Was the equipment used during breath-hold clear and understandable? | 3.9 |
| 3. Were the commands given by the technician understandable during breath-hold? | 3.8 |
| 4. Was it challenging to hold your breath? | 1.5 |
| 5. Was the CT scan time long? | 1.1 |
| 6. Did you experience stress during the CT scan? | 1.2 |
| 7. Were you worried because you took an active role in the CT scan? | 1.2 |
| Second questionnaire (After completion of Treatment) | 1–4 scale |
| 1. Did you find the training you received before the breath-hold procedure helpful? | 4 |
| 2. Was the equipment used during breath-hold clear and understandable? | 3.9 |
| 3. Were the commands given by the technician understandable during breath-hold? | 3.9 |
| 4. Was it challenging to hold your breath? | 1.6 |
| 5. Was the treatment period long? | 1.4 |
| 6. Did you experience stress during the treatment? | 1.5 |
| 7. Were you worried because you took an active role in the treatment? | 1.2 |
Pretreatment CBCT was done in the median of 2,6 BH (2–5, 7). The whole treatment time, including the CBCT taking period, evaluation for registration, and treatment delivery, was 14,4 minutes (9,1–24,6). The average beam on time was 7,23 minutes (1,44 − 16,43).
CBCT taking period and evaluation time was mean 7,18 minutes (4,47 − 13,17). All treatment has been completed in 7,1 BHs (3.6–16.3). A second CBCT imaging was done in one fraction for seven patients and two fractions in 1 patient due to the movement recognized by AlignRT. The gating margin was expanded from 3 to 4–5 mm in all fractions in 5 patients and one fraction in 2 patients. Surface guidance was deactivated in 1 fraction in 1 patient.
Dose per fraction (p:<0,001), dose rate (p:<0,001), and total monitor units (p:0,022) are associated with the beam-on time but not the PTV volume (p:0,19).
KPS, age, lung volume, or conditions affecting lung capacity, previous BH radiotherapy history, and being a native speaker are not associated with prolonged treatment time. Female patients have shorter treatment times in BH with SGRT treatments than male patients (p: 0,02).