Impact of prone versus supine positioning on small bowel dose with pelvic intensity modulated radiation therapy

Abstract

PurposeTo report the results of a prospective study that compares small bowel doses during prone and supine pelvic intensity modulated radiation therapy.Methods and materialsTen patients receiving pelvic radiation therapy each had 2 intensity modulated radiation therapy plans generated: supine and prone on a belly board (PBB). Computed tomography on rails was performed weekly throughout treatment in both positions (10 scans per patient). After image fusion, doses to small bowel (SB) loops and clinical target volume were calculated for each scan. Changes between the planned and received doses were analyzed and compared between positions. The impact of bladder filling on SB dose was also assessed.ResultsProne treatment was associated with significantly lower volumes of SB receiving ≥20 Gy. On average, prone on a belly board positioning reduced the volume of SB receiving a given dose of radiation by 28% compared with supine positioning. Target coverage throughout the treatment course was similar in both positions with an average minimum clinical target volume dose of 88% of the prescribed prone dose and 89% of the supine (P = .54). For supine treatment, SB dose was inversely correlated with bladder filling (P = .001-.013; P > .15 for prone). For 96% of treatments, the volume of SB that received a given dose deviated >10% from the plan. The deviation between the planned and delivered doses to SB did not differ significantly between the positions.ConclusionsProne positioning on a belly board during pelvic IMRT consistently reduces the volume of SB that receives a broad range of radiation doses. Prone IMRT is associated with interfraction dose variation to SB that is similar to that of supine positioning. These findings suggest that prone positioning with daily image guided radiation therapy is an effective method for maximizing SB sparing during pelvic IMRT.

Prone treatment position as a novel option for head and neck cancer patients with unmanageable secretions

“…Several studies have demonstrated that prone positioning provides enhanced normal tissue sparing in certain clinical scenarios. [6][7][8] Mullinez et al 6 conducted a study in 18 early-stage breast cancer patients who were undergoing whole-breast irradiation after having breast-conserving surgery. Dosimetric evaluation of plans for 6 patients comparing tangential wedge fields, tangential field IMRT, and multi-beam IMRT was performed in supine and prone for each patient.…”

“…The prone positioning did, however, significantly reduce the small bowel dose V5 and V10 volumes. 5 Ten patients undergoing pelvic radiation therapy were evaluated with both prone and supine treatment plans by Gonzales et al 8 to compare small bowel dose. They found that prone positioning resulted in a lower volume of small bowel receiving irradiation.…”

Daily Setup Accuracy, Side-effects and Quality of Life During and After Prone Positioned Prostate Radiotherapy

“…Radiation exposure of intestines is better in prone position with the use of BB, than in supine position, in case of 3D-CRT and IMRT technique, which may decrease the GI morbidity in itself (9). Gonzalez et al (10) found that a significantly smaller volume of the small intestine receives more than 20 Gy dose in prone position with the use of BB, while the interfraction dose variation to the small bowel was similar to the supine position. Bajon et al (11) have shown decreased dose exposure of the urinary bladder in prone position besides sparing the rectum and the small intestine.…”

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“…Radiation fields become widely used like radiological, diagnostic imaging, radiation therapy, nuclear and industrial applications thus fields can be harmful to human due to hazards radiation. The choice of shielding material has gained more attention to reduce biological effects of radition and depend on type of radiation, energy of that radiation and characteristics of the chosen material [34].…”