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The present study aimed to summarize and report data on errors related to treatment planning, which were collected by medical physicists. The following analyses were performed based on the 10-year error report data: (1) listing of high-risk errors that occurred and (2) the relationship between the number of treatments and error rates, (3) usefulness of the Automated Plan Checking System (APCS) with the Eclipse Scripting Application Programming Interface and (4) the relationship between human factors and error rates. Differences in error rates were observed before and after the use of APCS. APCS reduced the error rate by ~1% for high-risk errors and 3% for low-risk errors. The number of treatments was negatively correlated with error rates. Therefore, we examined the relationship between the workload of medical physicists and error occurrence and revealed that a very large workload may contribute to overlooking errors. Meanwhile, an increase in the number of medical physicists may lead to the detection of more errors. The number of errors was correlated with the number of physicians with less clinical experience; the error rates were higher when there were more physicians with less experience. This is likely due to the lack of training among clinically inexperienced physicians. An environment to provide adequate training is important, as inexperience in clinical practice can easily and directly lead to the occurrence of errors. In any environment, the need for additional plan checkers is an essential factor for eliminating errors. [ABSTRACT FROM AUTHOR]

The uterus is known as one of the moving organs. We evaluated the movement of the uterus during irradiation and the effects of changes in the surrounding organs using a magnetic resonance (MR)-guided radiotherapy system. Seven patients with cervical cancer underwent pre- and posttreatment MR imaging to assess changes in the positioning of the uterus and cervix as well as the alterations in bladder and rectal volume. The study revealed that the movements of the uterus were greater than that of the cervix and showed a tendency to correlate with the bladder rather than the rectum. We also examined whether intrafractional motion could lead to insufficient dose coverage of the clinical target volume (CTV), specifically focusing on the D 98% of the CTV in the uterine body and cervix. The impact of intrafractional motion on the D 98% varied among patients, with one out of the seven patients experiencing an average dosimetric change of −2.6 Gy in the uterus, although larger planning target volume margins of 1.5 cm were applied, therefore, indicating the need for individualized optimal margins in each case. Online adaptive radiotherapy offers the advantage of modifying the treatment plan when irradiating moving organs, such as the uterus. However, it should be noted that this approach may result in longer overall treatment times compared with the traditional methods. Therefore, we must carefully consider the influence of intrafractional organ motions when opting for such a treatment. [ABSTRACT FROM AUTHOR]

This study aimed to assess the dosimetric effect of intestinal gas of stereotactic magnetic resonance (MR)-guided adaptive radiation therapy (SMART) on target and critical organs for pancreatic cancer without online electron density correction (EDC). Thirty pancreatic cancer patients who underwent online SMART were selected for this study. The treatment time of each stage and the total treatment time were recorded and analyzed. The concerned dose-volume parameters of target and organs-at-risk (OAR) were compared with and without an intestinal gas EDC using the Wilcoxon-signed rank test. Analysis items with p value < 0.05 were considered statistically significant. The relationships between dosimetric differences and intestinal gas volume variations were investigated using the Spearman test. The average treatment time was 82 min, and the average EDC time was 8 min, which accounted for 10% of the overall treatment time. There were no significant differences in CTV (GTV), PTV, bowel, stomach, duodenum, and skin (p > 0.05) with respect to dose volume parameters. For the Dmax of gastrointestinal organs (p = 0.03), the mean dose of the liver (p = 0.002) and kidneys (p = 0.03 and p = 0.04 for the left and right kidneys, respectively), there may be a risk of slight overestimation compared with EDC, and for the Dmax of the spinal cord (p = 0.02), there may be a risk of slight underestimation compared with EDC. A weak correlation for D95 in the PTV and D0.5 cc in the duodenum was observed. For patients with similar inter-fractional intestinal gas distribution, EDC had little dosimetric effects on the D0.5 cc of all GI organs and dose volume parameters of target in most plans. By omitting the EDC of intestinal gas, the online SMART treatment time can be shortened. [ABSTRACT FROM AUTHOR]