PURPOSETo determine an efficient strategy for the generation of the internal target volume (ITV) for radiation treatment planning for esophageal cancer using 4-dimensional computed tomography (4DCT).METHODS AND MATERIALS4DCT sets acquired for 20 patients with esophageal carcinoma were analyzed. Each of the 4DCT sets was binned into 10 respiratory phases. For each patient, the gross tumor volume (GTV) was delineated on the 4DCT set at each phase. Various strategies to derive ITV were explored, including the volume from the maximum intensity projection (MIP; ITV_MIP), unions of the GTVs from selected multiple phases ITV2 (0% and 50% phases), ITV3 (ITV2 plus 80%), and ITV4 (ITV3 plus 60%), as well as the volumes expanded from ITV2 and ITV3 with a uniform margin. These ITVs were compared to ITV10 (the union of the GTVs for all 10 phases) and the differences were measured with the overlap ratio (OR) and relative volume ratio (RVR) relative to ITV10 (ITVx/ITV10).RESULTSFor all patients studied, the average GTV from a single phase was 84.9% of ITV10. The average ORs were 91.2%, 91.3%, 94.5%, and 96.4% for ITV_MIP, ITV2, ITV3, and ITV4, respectively. Low ORs were associated with irregular breathing patterns. ITV3s plus 1 mm uniform margins (ITV3+1) led to an average OR of 98.1% and an average RVR of 106.4%.CONCLUSIONSThe ITV generated directly from MIP underestimates the range of the respiration motion for esophageal cancer. The ITV generated from 3 phases (ITV3) may be used for regular breathers, whereas the ITV generated from 4 phases (ITV4) or ITV3 plus a 1-mm uniform margin may be applied for irregular breathers.

2012-07-01·Practical Radiation Oncology4区 · 医学

Determination of internal target volume using selective phases of a 4-dimensional computed tomography scan

4区 · 医学

Article

作者: Werner-Wasik, Maria ; Cui, Yunfeng ; Liu, Haisong ; Champ, Colin E ; Cao, Junsheng ; Xiao, Ying ; Yu, Yan

PURPOSEInternal target volume (ITV) is frequently determined by contouring of gross tumor volumes (GTV) on 10 phases of a 4-dimensional computed tomography (4DCT) study set for lung cancer radiotherapy. This study aimed to investigate the possibility of generating ITV by using selective phases of a 4DCT scan.METHODS AND MATERIALSThe 4DCT scans of 20 patients with lung cancer were included in this study. GTVs were contoured on 10 phases in Focal4D (CMS, St Louis, MO). Different ITVs were derived by encompassing volumes of contours from selective phases. ITV10 was the combination of GTVs on all of the 10 phases and served as the gold standard volume. All of the other ITVs were smaller and within ITV10. The ratios of the volumes of these ITVs to ITV10 were calculated and used as a criterion to determine the similarity of different ITVs to ITV10. ITV2 represented the ITV derived by using end-inhalation and end-exhalation (0% + 50%). ITV3E was derived from contouring the 3 phases at end-inhalation, mid-exhalation, and end-exhalation (0% + 20% + 50%). ITV3I was derived from contouring the 3 phases at end-inhalation, mid-inhalation, and end-exhalation (0% + 70% + 50%). ITV4 was derived by contouring the 4 phases at end-inhalation, mid-inhalation, end-exhalation, and mid-exhalation (0% + 20% + 50% + 70%). ITV6E was derived from contouring the 6 consecutive phases during exhalation (0% + 10% + 20% + 30% + 40% + 50%). ITV6I was derived from contouring the 6 consecutive phases during inhalation (50% + 60% + 70% + 80% + 90% + 0%). The volumes of ITVs were calculated and compared.RESULTSITV6I showed excellent agreement with ITV10 (volume ratio ITV6I/ITV10 = 0.975). ITV4 and ITV6E showed good agreement with ITV10 (ITV6E/ITV10 = 0.939, ITV4/ITV10 = 0.944). The volume ratios ITV3I/ITV10 and ITV3E/ITV10 were 0.927 and 0.906, respectively. ITV2 did not agree well with ITV10 (ITV2/ITV10 = 0.888).CONCLUSIONSContouring all phases during inhalation provides a good estimate of the ITV. However, the ITV may be underestimated if only contouring on 2 extreme phases.

1999-06-01·The Journal of Infectious Diseases2区 · 医学

Reemergence of Adenovirus Type 4 Acute Respiratory Disease in Military Trainees: Report of an Outbreak during a Lapse in Vaccination

2区 · 医学

Article

作者: Barraza, E M ; Gaydos, J C ; Ludwig, S L ; Brundage, J F

From 23 April to 13 May 1995, an outbreak of acute respiratory disease (ARD) hospitalizations occurred in basic training soldiers at Fort Jackson, South Carolina. Weekly hospitalization rates for the most affected military unit reached 11.6%. Virus isolation and serologic studies from a sample of patients identified the agent as adenovirus type 4. Prior to starting vaccinations against adenovirus types 4 and 7 in 1971, these serotypes were the major causes of ARD in basic trainees. No outbreaks were reported when the vaccines were used. A logistical error temporarily interrupted vaccine production, and newly arriving trainees received no adenovirus vaccines from the summer of 1994 through late March 1995. This outbreak occurred in unvaccinated soldiers. The sole manufacturer has permanently stopped adenovirus vaccine production. All type 4 vaccine supplies are now depleted. This outbreak demonstrates continued susceptibility of military recruits to adenovirus type 4 and warns of future outbreaks.

100 项与 ITV-4 相关的药物交易

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