title: Short-term clinical outcome and dosimetric comparison of tandem and ring versus tandem and ovoids intracavitary applicators.
abstract: OBJECTIVE
  To compare the short-term toxicity and dosimetry of tandem and ring (TR), and tandem and ovoid (TO) applicators in treatment of gynecologic malignancy.
  
  
  METHODS
  Following pelvic external beam radiation therapy (EBRT), a total of 52 computed tomography-based plans from 13 patients with cervical cancer (FIGO IB2-IIIB) were evaluated for HDR brachytherapy. Prescription was 7 Gy to the ICRU point A for four weekly fractions. Gastrointestinal and genitourinary toxicities were evaluated. Clinical target volume (CTV) and organs at risk were delineated on CT scans. Bladder, rectum, and sigmoid mean doses and D2cc were calculated. Treatment time and irradiated tissue volume were compared. Percent of CTV receiving 100% (CTV100%) of the prescribed dose as well as the percent of the prescription dose covering 90% of the CTV (D90) were evaluated.
  
  
  RESULTS
  Gastrointestinal and genitourinary toxicities were not different between TO and TR applicators. No significant differences in the dose to the right and left point A, or the left point B were observed. TO delivered a higher dose to right point B. Organs at risk doses were similar between the two applicators, except mean rectal dose was lower for TO applicator. Overall, TO treats a larger tissue volume than TR. Mean treatment time was shorter for TR. Tumor coverage (D90 and CTV100%) was equivalent between TO and TR applicators.
  
  
  CONCLUSIONS
  Although TO treats a larger tissue volume than TR, short-term toxicities and tumor coverage are similar. Long-term clinical outcomes will be elucidated with longer follow up period.
authors.affiliation: Department of Radiation Oncology.
authors.forename: John K
authors.initials: JK
authors.lastname: Ma
authors.affiliation: Department of Medicine, University of Mississippi, Jackson, MS, USA.
authors.forename: Waleed F
authors.initials: WF
authors.lastname: Mourad
authors.affiliation: Department of Radiation Oncology.
authors.forename: Robert
authors.initials: R
authors.lastname: Allbright
authors.affiliation: Department of Radiation Oncology.
authors.forename: Satyaseelan
authors.initials: S
authors.lastname: Packianathan
authors.affiliation: Department of Radiation Oncology.
authors.forename: Leslie M
authors.initials: LM
authors.lastname: Harrell
authors.affiliation: Department of Medicine, University of Mississippi, Jackson, MS, USA.
authors.forename: Edmund
authors.initials: E
authors.lastname: Chinchar
authors.affiliation: Department of Radiation Oncology.
authors.forename: Alex
authors.initials: A
authors.lastname: Nguyen
authors.affiliation: Department of Radiation Oncology.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Vijayakumar
keywords: brachytherapy; cervical cancer; dosimetry; radiation toxicity