## 3 Results
### Training and Patient Education before DIBH  
A study by [PERSON] et al. confirmed that there was less cardiac irradiation after DIBH in patients who practiced the breath-holding technique at home about a week before treatment [19]. Participants in the study were instructed exactly according to the regimen by specialists what exercises to perform in order to have the desired effect. The training was primarily focused on controlling breath holding in the treatment position for 40 s while immobilizing the chest. The maximum cardiac dose during DIBH in the group without training (19.4 Gy) accounted for 0.38% to 0.48% of the total target dose, while in the group with training (13.1 Gy), it accounted for 0.26% to 0.33% of the total target dose. It has been noted that the reduction in irradiation mainly involves the part of the heart closest to the chest (i.e., coronary vessels, left ventricle). Radiation dose to specific cardiac structures, especially the left ventricle, is strongly associated with the risk of acute coronary events. This suggests that reducing the maximum cardiac dose, even slightly, could potentially translate into a reduced risk of cardiovascular complications in patients [19]. The effect of individual patient training carried out over a short period of time (1-2 weeks) may be influenced by psychological factors, neurocognitive factors, and abdominal muscle strengthening [24]. This was confirmed by [PERSON] et al. by training 112 patients one week before DIBH irradiation with the type and technique of breathing exercises. The researchers noted that for patients who had trained prior to undergoing the treatment, the treatment session time was half the time of the patients who had no prior preparation to their treatment. One of the key conclusions that ought to be taken from the research is that  
Figure 1: PRISMA flowchart study selection process. Identification of studies via databases and registers.  
the level of satisfaction after training was high [25]. These results are consistent with the study by [PERSON] et al. Here, the researchers enrolled 20 patients in their training on how to correctly perform breathing maneuvers. The training that had been carried out by the researchers was both visual and spoken. They assessed that the abdominal maneuver achieved significantly lower doses on the heart during DIBH compared to the thoracic maneuver. This provides an opportunity for further research and training using both maneuvers in patients prior to breath-hold radiation therapy [26]. [PERSON] et al. stressed that the integration of DIBH into routine clinical procedures creates difficulty in ensuring consistent patient configuration during treatment due to the need to train them. In order to achieve reproducibility of position, the rate of sparing normal tissue and feasibility of administration for voluntary DIBH were compared to DIBH with a dedicated system, such as the Active Breathing Coordinator (ABC) [11].  
The effectiveness of treatment and patient selection for DIBH is affected by training and patient education [19; 23; 24; 25]. Patient training helps reduce cardiac complications after DIBH. An additional advantage that was observed was the reduction in therapy time. Consequently, the results of heart-sparing therapy are better [26]. The intra-fractional and inter-fractional types of patient reproducibility are important to confirm that the estimated dose to the heart is consistent with the dose actually administered. These challenges require a comprehensive evaluation of the factors affecting both the efficacy and potential drawbacks of radiotherapy.