Uterine artery embolization: reduced radiation with refined technique.

PURPOSE: To determine the estimated absorbed ovarian dose (EAOD) and absorbed skin dose (ASD) that occurs during uterine artery embolization (UAE) using pulsed fluoroscopy and a refined procedure protocol. MATERIALS AND METHODS: The absorbed dose was measured in 20 patients who underwent UAE procedures. Radiation was limited by using low frequency pulsed fluoroscopy, bilateral catheter technique with simultaneous injections for embolization as well as pre-and postembolization exposures and focus on limitation of magnified and oblique fluoroscopy. Lithium fluoride dosimeters were placed both in the posterior vaginal fornix and on the skin at the beam entrance site. The vaginal dose was used to approximate the EAOD. Fluoroscopy time and exposures were recorded. The mean values for all patients were calculated and compared to our previous results obtained with conventional fluoroscopy and to threshold doses for the induction of deterministic skin injury. RESULTS: Mean fluoroscopy time was 10.95 min. (range 6-21.3 min.) and the mean number of angiographic exposures was 20.9 (range 14-53). The mean EAOD was 9.5 cGy (range 2.21-23.21 cGy) and the mean ASD was 47.69 cGy (range 10.83-110.14 cGy). This compares to previous results with non-pulsed fluoroscopy of an EAOD of 22.34 cGy (range 4.25-65.08 cGy) and an ASD of 162.32 cGy (range 66.01-303.89 cGy) as well as threshold doses for induction of deterministic radiation injury to the skin (400-500 cGy). CONCLUSION: When pulsed fluoroscopy is used with emphasis on dose reduction techniques, the EAOD and ASD can be substantially reduced to less than 1/2 (P = .017) and 1/3 (P < .0001) when compared to UAE performed with nonpulsed fluoroscopy. These radiation reduction tools should therefore be applied whenever possible.

Influence of radiographic technique and equipment on absorbed ovarian dose associated with uterine artery embolization.

PURPOSE: To evaluate the influence of pulsed fluoroscopy (PF), nonpulsed fluoroscopy (NPF), and various fluoroscopic techniques on the absorbed ovarian dose (AOD) associated with uterine artery embolization (UAE) of leiomyomata. MATERIAL AND METHODS: Ovarian location was estimated from preprocedural pelvic magnetic resonance images of 23 patients previously treated by means of UAE. The AOD was measured with thermoluminescent dosimeters (TLD) placed into an anthropomorphic phantom at the determined ovarian location. The following measurements from PF and NPF were obtained: 21.89 minutes of nonmagnified posterior-anterior fluoroscopy, 10 minutes of nonmagnified oblique fluoroscopy, 10 minutes of posterior-anterior magnified fluoroscopy, 10 minutes of combined oblique magnified fluoroscopy, and 47 simulated angiographic exposures. Numbers for nonmagnified posterior-anterior fluoroscopy time and exposure numbers were chosen from the average values from previous UAE procedures. AOD from pulsed and nonpulsed nonmagnified posterior-anterior fluoroscopy was compared to measurements from oblique magnified, posterior-anterior magnified, and oblique fluoroscopy. RESULTS: AOD from NPF was, on average, 1.7 times higher than from PF. When compared with nonmagnified posterior-anterior fluoroscopy, the AOD from oblique magnified fluoroscopy was 1.9 times greater; the AOD from nonmagnified oblique fluoroscopy was 1.1 times greater. The AOD from oblique magnified fluoroscopy was 1.5 times higher on the side closer to the x-ray tube than on the contralateral side. AOD from serial angiographic exposures contributed only less than 7% to the total AOD for the average UAE procedure. CONCLUSIONS: The AOD associated with UAE can best be reduced by limiting fluoroscopy time and the use of oblique or magnified fluoroscopy. Contribution of angiographic exposures to AOD is much less significant.

Patient radiation dose associated with uterine artery embolization.

PURPOSE: To evaluate the estimated absorbed radiation doses to the ovaries and skin entrance during uterine artery embolization (UAE) for leiomyomas. MATERIALS AND METHODS: Radiation dose was measured in 20 patients who underwent UAE for leiomyomas. Measurements were obtained by placing lithium fluoride dosimeters both into the posterior fornix of the vagina and on the skin at the beam entrance site. Patient doses were obtained with thermoluminescent dosimeters. RESULTS: The mean fluoroscopic time was 21.89 minutes, and the mean number of angiographic exposures was 44. The mean estimated absorbed ovarian dose was 22.34 cGy, and the mean absorbed skin dose was 162.32 cGy. These values compare to published values for the assessed absorbed ovarian dose during hysterosalpingography (0.04-0.55 cGy), fallopian tube recanalization (0.2-2.75 cGy), computed tomography of the trunk (0.1-1.9 cGy), and pelvic irradiation for Hodgkin disease (263-3,500 cGy). CONCLUSION: The estimated absorbed ovarian dose during UAE is greater than that during common fluoroscopic procedures. On the basis of the known risks of pelvic irradiation for Hodgkin disease, the dose associated with UAE is unlikely to result in acute or long-term radiation injury to the patient or to a measurable increase in the genetic risk to the patient's future children.

Intratumoral radioimmunotherapy of a human colon cancer xenograft using a sustained-release gel.

Low tumor uptake and normal tissue toxicity limit the efficacy of RIT for the treatment of solid tumors. In this study, an intratumoral injectable gel drug delivery system for local administration of RIT was evaluated using the LS174T human colon cancer xenograft model in SCID mice. The injectable gel is a collagen-based drug delivery system designed for intratumoral (i.t.) administration, which has previously been shown to enhance drug retention at the injection site and reduce systemic drug exposure. We compared the local (tumor) retention and biodistribution of 111In-labeled NR-LU-10 monoclonal antibody given i.t. in the injectable gel versus simple aqueous solution. 111In gel given i.t. and 111In-NR-LU-10 given intraperitoneally (i.p.) were used as controls. The results showed that tumors treated with 111In-NR-LU-10 gel maintained the highest levels of radioactivity for up to 96 h. At 48 h after the administration of 111In-NR-LU-10 gel i.t., 111In-NR-LU-10 solution i.t., 111In gel i.t., or 111In-NR-LU-10 i.p., the level of radioactivity remaining in each gram of tumor was 98, 49, 45, and 16% of the injected dose, respectively. It was estimated that if 100 microCi of 90Y-NR-LU-10 were administered similarly, tumor treated with 90Y-NR-LU-10 gel i.t. would receive a dose of 90.0 Gy, whereas normal tissues in the same animal would receive a dose of approximately 2.43 Gy. In contrast, if 90Y-NR-LU-10 were delivered i.p., a comparable tumor would receive a dose of 16.8 Gy and corresponding normal tissues would receive 3.36 Gy. Consistent with these estimates, enhanced antitumor efficacy was observed when 90Y-NR-LU-10 gel was administered i.t. Tumor growth delay time was 6.9-fold (P < 0.01) longer in these animals (14.4 days) than in animals treated with 90Y-NR-LU-10 i.p. (2.1 days). Systemic toxicity was also significantly reduced in gel-treated animals as monitored by loss of body weight. This study demonstrated that intratumoral delivery of 90Y-NR-LU-10 gel markedly increased the retention of the radioisotope in tumors, enhanced the antitumor efficacy, and reduced systemic toxicity compared to systemic administration of the radiolabeled antibody. This injectable gel drug delivery system may allow for improvement in the therapeutic index for RIT.