Proceedings of the 52nd Annual ASTRO Meeting S843

lower than IMRT plans ,and the f-IMRT plans showed the lowest value. For the V20 and V30 in left lung, the IMRT and RAplans were statistically significant lower than f-IMRT plans, and the RA plans showed the lowest value. The maximum doseand V40 in heart were lowest for the RA plans, and RA plans showed statistically significant lower for the mean dose in heartvs. IMRT plans. The V5, V10 and the mean dose in right lung, and the mean dose to the contra-lateral breast were lowest for f-IMRT plans. No statistically significant differences were observed in these indexes for IMRT vs. RA plans. The maximumdose to the contra-lateral breast was lowest for RA plans. For the number of MU,IMRT and f-IMRT plans showed the highestand lowest value respectively. The RA plans reduced the delivery time by 84.6%and 88.23% compared to f-IMRT and IMRTplans.

Conclusions: Compared to f-IMRT and IMRT plans, the RA plans showed a better conformity in target, reduced the irradiatedvolume of high dose region in the left lung and heart as well as significantly decreased the delivery time. Compared to IMRT plans,the RA plans could also reduce the irradiated volume of low dose region in the left lung and the Mus significantly.

Author Disclosure: T. Sun, None; Y. Yin, None; X. Lin, None; T. Liu, None; J. Lu, None.

3429 Clinical Aspects of a Simple and Effective Method to Perform Stereotactic Body Radiation Therapy

(SBRT) of Lung without 4D-CT and Gating

P. Volpp, S. Jani, G. Weinstein, N. Shah, J. Pothilat, S. Glazebrook

Sharp Memorial Hospital, San Diego, CA

Purpose/Objective(s): In recent years, there has been considerable debate about the necessity of using respiratory gating and 4D-CT to perform SBRT, a fast-growing practice with high risk to patients. Here, we describe early clinical results of a method toperform SBRT in lung patients without the use of respiratory gating and 4D-CT.

Materials/Methods: Under our protocol, each patient underwent a CT-guided placement of a Visicoil marker. Patients wereimmobilized with a homegrown method utilizing a Vac-loc and Aquaplast body cast; then underwent a fluoroscopic examwith a C-Arm to determine tumor motion. Normal tissues dose limits were set using RTOG/ M.D. Anderson guidelines onlung SBRT. Treatments were carried out at a BrainLab Novalis system using Dynamic arc techniques under ExacTrac imageguidance. A total of 12 patients and 13 lesions were treated from February 2009 to present. Patient ages ranged from 53 to89 with a median age of 74.8 years. Majority of patients received 50 Gy in either 4 or 5 fractions. Average target dimensionswere 19cc (GTV) and 81cc (PTV). The lung DVH (V-20), based on whole lung-GTV, ranged from 3.1% to 11% with anaverage of 7.8%. Mean follow-up was 5.3 months with a range of 2 to 11 months. Target movement as determined fromfluoroscopy over several breathing cycles ranged from 2 to 20 mm in cranio-caudal direction, 0-15 mm in anterio-posteriordirection and 0-5 mm laterally. As reported by others, we found the RTOG margins to be inadequate in about 25% of thelesions.

Results: All 12 patients were found to be controlled locally as of the most recent follow-up. Two of the 12 patients, however, haddeveloped disease elsewhere. One patient died of progressive disease bilaterally in the lungs and another was recently found to haveperitoneal carcinomatosis. No patient showed evidence of Grade III toxicity.

Conclusions: Based on early follow-up of a small cohort of patients, we believe that respiratory gating and 4D-CT may not to beessential components of SBRT. Our experience taught us that radio-opaque markers and image guidance were necessary for thesehigh-risk procedures. As pointed out by recent ASTRO/ACR guidelines, the truly critical aspect of SBRT is rigorous QA of eachprocess.

Author Disclosure: P. Volpp, None; S. Jani, None; G. Weinstein, None; N. Shah, None; J. Pothilat, None; S. Glazebrook, None.

3430 A Simple Brachytherapy Catheter Spacing Technique

K. M. Sokolov1, J. Demanes1, J. K. Hayes2

1UCLA Center for Health Sciences, Los Angeles, CA, 2Gamma West Brachytherapy, Salt Lake City, UT

Purpose/Objective(s): We describe a simple technique to facilitate catheter spacing, implant stability, and patient comfort duringmulti-catheter interstitial brachytherapy.

Materials/Methods: Disconnected multiple tube and button implant catheters inserted freehand are prone to irregular spacing.Catheter displacement may occur after the procedure and external fixing buttons may cause pressure injury to the skin. Wehave developed a simple, inexpensive alternative to current practice that controls catheter spacing and provides comfort and sta-bility in the treatment of breast, head and neck, sarcoma and other sites. Fenestrated surgical drains are used to guide and stabilizethe implant catheters. Jackson-Pratt (JP) drains with radioopaque surface markings at 1cm interval fenestrations are used in mostcases. They are placed perpendicular to the direction of implant needles during needle insertion. The catheters are then threadedthrough the holes in the sides of the drains allowing the desired spacing to be achieved and maintained. Small round JP drains (10French round) placed on the skin (sometimes also the mucosa) are most suitable for breast and head and neck sites. Larger flat JPdrains (7 mm flat) are used both on the skin and within the tumor bed for intraoperative cases involving extremity sarcoma, ab-dominal, or thoracic tumors. The tumor bed drains are laid parallel to the skin within the wound (via separate drain incisions).The catheter-applicator unit can be further secured with friction buttons and by suturing the surface drains to the skin. Followingtreatment delivery, it is essential to first remove the implant catheters before removing the drains.

Results: The brachytherapy surgical drain applicator unit creates and maintains stable internal and external geometry for multiplecatheter interstitial implants both after wound closure and during the treatment delivery process. Catheter displacement is unusualand skin injury is reduced. The technique results in few complications.

Conclusions: This simple and inexpensive brachytherapy catheter technique provides improved implant geometry and stability.Dosimetry is thus more faithfully rendered during brachytherapy treatment delivery. Patient comfort and tolerance are alsoimproved as the soft surgical drain protects the patient’s skin.

Author Disclosure: K.M. Sokolov, None; J. Demanes, None; J.K. Hayes, None.