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Dwight E Heron

Publications and source records attributed to Dwight E Heron.

At least 19 recordsLinked to original sources
PubMed2006

Dosimetric and toxicity comparison between prone and supine position IMRT for endometrial cancer.

PURPOSE: To determine the dosimetric and toxicity differences between prone and supine position intensity-modulate radiotherapy in endometrial cancer patients treated with adjuvant radiotherapy. METHODS: Forty-seven consecutive endometrial cancer patients treated with adjuvant RT were analyzed. Of these, 21 were treated in prone position and 26 in the supine position. Dose-volume histograms for normal tissue structures and targets were compared between the two groups. Acute and chronic toxicity were also compared between the cohorts. RESULTS: The percentage of volume receiving 10, 20, 30, 40, 45, and 50 Gy for small bowel was 89.5%, 69%, 33%, 12.2%, 5%, and 0% in the prone group and 87.5%, 62.7%, 26.4%, 8%, 4.3%, and 0% in the supine group, respectively. The difference was not statistically significant. The dose-volume histograms for bladder and rectum were also comparable, except for a slightly greater percentage of volume receiving 10 Gy (1.5%) and 20 Gy (5%) for the rectum in the prone group. Acute small bowel toxicities were Grade 1 in 7 patients and Grade 2 in 14 patients in the prone group vs. Grade 1 in 6 patients and Grade 2 in 19 patients in the supine group. Chronic toxicity was Grade 1 in 7 patients and Grade 3 in 1 patient in the prone group and Grade 1 in 5 patients in the supine group. CONCLUSION: These preliminary results suggest that no difference exists in the dose to the normal tissue and toxicity between prone and supine intensity-modulated radiotherapy for endometrial cancer. Longer follow-up and more outcome studies are needed to determine whether any differences exist between the two approaches.

Adult↗
PubMed2006

Dosimetric effects of patient rotational setup errors on prostate IMRT treatments.

The purpose of this work is to determine dose delivery errors that could result from systematic rotational setup errors (DeltaPhi) for prostate cancer patients treated with three-phase sequential boost IMRT. In order to implement this, different rotational setup errors around three Cartesian axes were simulated for five prostate patients and dosimetric indices, such as dose-volume histogram (DVH), tumour control probability (TCP), normal tissue complication probability (NTCP) and equivalent uniform dose (EUD), were employed to evaluate the corresponding dosimetric influences. Rotational setup errors were simulated by adjusting the gantry, collimator and horizontal couch angles of treatment beams and the dosimetric effects were evaluated by recomputing the dose distributions in the treatment planning system. Our results indicated that, for prostate cancer treatment with the three-phase sequential boost IMRT technique, the rotational setup errors do not have significant dosimetric impacts on the cumulative plan. Even in the worst-case scenario with DeltaPhi=3 degrees, the prostate EUD varied within 1.5% and TCP decreased about 1%. For seminal vesicle, slightly larger influences were observed. However, EUD and TCP changes were still within 2%. The influence on sensitive structures, such as rectum and bladder, is also negligible. This study demonstrates that the rotational setup error degrades the dosimetric coverage of target volume in prostate cancer treatment to a certain degree. However, the degradation was not significant for the three-phase sequential boost prostate IMRT technique and for the margin sizes used in our institution.

Body Burden↗
PubMed2006

Posttreatment assessment of response using FDG-PET/CT for patients treated with definitive radiation therapy for head and neck cancers.

PURPOSE: The goal of this study was to evaluate coregistered [18F] fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) for the detection of persistent disease after definitive radiation therapy in head and neck cancer. METHODS AND MATERIALS: Posttreatment FDG-PET/CT was performed in 28 patients on average 8 weeks (range, 4 to 15.7 weeks) after completing definitive radiation therapy. FDG-PET/CT was visually analyzed for the entire patient group and at two time points (4-8 and >8 weeks) after treatment. The contrast-enhanced CT portion of PET/CT was separately analyzed blinded to the results of coregistered FDG-PET/CT and classified as negative or positive for residual locoregional disease. Pathologic findings and clinical follow-up served as the reference standard. RESULTS: Follow-up data were available for all 28 patients (median, 17.6 months). Regarding the detection of residual disease, the overall sensitivity and specificity of FDG-PET/CT was 76.9% and 93.3%, respectively, compared with 92.3% and 46.7% for contrast-enhanced CT. The accuracy of FDG-PET/CT was 85.7%, compared with 67.9% for CT alone. All false-negative (n = 3) and false-positive (n = 1) FDG-PET/CT results occurred between 4 and 8 weeks after treatment. At 8 weeks or later after treatment, the specificity of CT was 28%, compared with 100% for FDG-PET/CT. CONCLUSIONS: The metabolic-anatomic information from coregistered FDG-PET/CT provided the most accurate assessment for treatment response when performed later than 8 weeks after the conclusion of radiation therapy. FDG-PET/CT excelled by a higher specificity and overall diagnostic performance than CT imaging alone. These results support a potential clinical role of FDG-PET/CT in the early assessment of therapy response after definitive radiation therapy.

Adult↗
PubMed2006

Clinical outcome with adjuvant treatment of endometrial carcinoma using intensity-modulated radiation therapy.

OBJECTIVE: To assess local control and chronic toxicity with IMRT for adjuvant treatment of endometrial carcinoma. METHODS: Forty-seven patients with endometrial cancer were treated with adjuvant IMRT and HDR brachytherapy (HDRB). The external beam dose was between 45 and 50.4 Gy, and all patients received 10 Gy in 2 fractions of HDRB to the vaginal cuff. Eight of these patients were treated with extended field to include the paraaortic region. RESULTS: IMRT dosimetry showed excellent coverage of the planning target volume (PTV) with mean PTV 95, PTV 110 and PTV 120 of 97.8%, 8.2% and 0.9% respectively. At a median follow-up of 20 months, four patients have recurred at extra pelvic sites. No patient had pelvic recurrence. The treatment was well tolerated with late toxicities as follows: small bowel grade 1: 25%, rectal grade 1: 2% and bladder grade 1: 13%. One patient had grade 3 small bowel toxicity. The 3-year actuarial rate of grade 2 or greater toxicity, disease-free survival and overall survival rate were 3.3%, 84% and 90%, respectively. CONCLUSIONS: The preliminary analysis of IMRT for adjuvant treatment of endometrial carcinoma shows excellent local control and low toxicity. However, longer follow-up and more patients are needed to ascertain whether the benefits of IMRT treatment seen here translate into long-term reductions in toxicities and local recurrence.

Adult↗
PubMed2006

External beam radiotherapy boosts to reduce the impact caused by edema in prostate permanent seed implants.

In prostate permanent seed implants, it has been shown that edema caused by the surgical procedure decreases dose coverage and hence may reduce treatment efficacy. This reduction in treatment efficacy has been characterized by an increase in tumour cell survival, and biomathematical models have been developed to calculate the tumour cell survival increases in seed implanted prostates of different edema magnitudes and durations. External beam boosts can be utilized to neutralize the negative impact of edema so that originally desired treatment efficacy can be achieved. In this study, a linear quadratic model is used to determine fractionation sizes of the external beam boosts for both (125)I and (103)Pd seed implants. Calculations were performed for prostates of different edema magnitudes and durations, and for tumour cells of different repair rates and repopulation rates.

Brachytherapy↗
PubMed2006

Feasibility of concurrent cisplatin and extended field radiation therapy (EFRT) using intensity-modulated radiotherapy (IMRT) for carcinoma of the cervix.

OBJECTIVES: To assess the acute tolerance of delivering concurrent cisplatin and extended field radiotherapy (EFRT) using intensity-modulated radiotherapy technique (IMRT) for cancer of the cervix. METHODS: All patients receiving definitive treatment for cervical cancer were treated with EFRT using IMRT technique and concurrent cisplatin. The treatment volume included the cervix, uterus, parametria, presacral space, upper vagina, pelvic, common iliac, and paraaortic nodes to the top of L1. All regions received 45 Gy (25 fractions) with a simultaneous boost to involved nodes (55 Gy/25 fractions). Patients were assessed weekly for toxicity and response. RESULTS: Twenty-two consecutive patients underwent treatment. All patients completed the prescribed course of EFRT. Median treatment length was 39.5 days (range 36-53). Treatment breaks of 2 and 3 days were required for bone marrow toxicity in 2 patients. The final week of chemotherapy was held in 2 patients because of neutropenia. No patient suffered acute or subacute grade 3 or 4 GI or GU toxicity. CONCLUSION: In this clinical study, an IMRT technique was used to successfully deliver EFRT with concurrent chemosensitization for cervical cancer. The technique was associated with an acceptable acute toxicity without significant treatment protraction. This new role for IMRT merits further evaluation with larger patient numbers and longer follow-up.

Adult↗
PubMed2006

A single institutional experience with definitive radiotherapy for cervical cancer using both high- and low-dose-rate brachytherapy.

OBJECTIVE: To evaluate outcomes in cervical cancer patients treated with high-dose-rate (HDRB) or low-dose-rate (LDRB) brachytherapy. METHODS: A retrospective chart review compared control rates, survival, and complications in the two groups. RESULTS: All patients received pelvic EBRT (45 Gy/5 weeks). 106 patients receiving LDRB were compared to 107 treated with HDRB. The median point A LDRB and HDRB dose was 42 Gy and 25 Gy/5, respectively. Tumor size and stage (I(B) 23% LDRB, 30% HDRB, II(A) 22% LDRB, 11% HDRB, II(B) 44% LDRB, 48% HDRB, III(B) 11% LDRB and HDRB) were similar, but more HDRB patients received chemosensitization (44% versus 6%). After adjusting for lymph node status with cox regression, no difference in 5-year survival (53% HDRB and 61% LDRB P = 0.088) or 5-year DFS (54% both groups, P = 0.089) was found between the two groups. Local recurrences occurred in 19% of the LDRB and 5% of the HDRB cohort. The time to LR was significantly longer in the HDRB group, and this persisted after adjusting for the increased used of chemotherapy in these patients. There was no significant difference in grade III or IV toxicity (6.6% LDRB and 3.7% HDRB). CONCLUSIONS: This HDRB dose fractionation schedule yielded improved local control but similar survival compared to LDRB.

Adult↗
PubMed2006

Intensity-modulated radiotherapy for the treatment of vulvar carcinoma: a comparative dosimetric study with early clinical outcome.

OBJECTIVES: To assess early clinical outcome of intensity-modulated radiation therapy (IMRT) in the treatment of vulvar cancer and compare dosimetric parameters with 3D conformal radiotherapy (3D CRT). METHODS: Fifteen patients with vulvar cancer were treated with IMRT. Seven patients were treated with preoperative chemoradiation, and 8 patients were treated with adjuvant postoperative radiation therapy. Median dose was 46 Gy in the preoperative and 50.4 Gy in the postoperative group. RESULTS: The mean volume of small bowel, rectum, and bladder that received doses in excess of 30 Gy with IMRT was reduced when compared with 3D CRT. Treatment was well tolerated, and only 1 patient had acute Grade 3 small-bowel toxicity. Median follow-up was 12 months. In the preoperative group, 5 patients (71%) had clinical complete response and 3 patients (42.8%) had pathologic complete response. In the adjuvant group, 2 patients had recurrences in the treatment field. No patients had late Grade 3 toxicity. The 2-year actuarial disease-specific survival was 100%. CONCLUSIONS: Intensity-modulated RT appears to offer advantages over 3D CRT treatment of vulvar cancer by elimination of dose modulation across overlapping regions and reduction of unnecessary dose to the bladder, rectum, and small bowel. Early results with a small number of patients show promising results, with a low incidence of severe toxicity.

Adult↗
PubMed2006

Modern radiation treatment planning and delivery--from Röntgen to real time.

The field of radiation oncology has advanced exponentially since the discovery of X-rays just over 100 years ago. With the advent of three-dimensional treatment planning, the therapeutic index was increased by dose escalation and more accurate shielding of normal tissues. Now, even greater advances are under way with IMRT, image-guided radiation therapy, delineation and control of organ motion, and real-time imaging. Similarly, the use of particle therapies such as protons has the potential to effect even more accurate dose distributions. Clinical studies investigating these modalities will likely further increase the efficacy of radiation in years to come.

Female↗
PubMed2006

Advances in image-guided radiation therapy--the role of PET-CT.

In the era of image-guided radiation therapy (IGRT), the greatest challenge remains target delineation, as the opportunity to maximize cures while simultaneously decreasing radiation dose to the surrounding normal tissues is to be realized. Over the last 2 decades, technological advances in radiographic imaging, biochemistry, and molecular biology have played an increasing role in radiation treatment planning, delivery, and evaluation of response. Previously, fluoroscopy formed the basis of radiation treatment planning. Beginning in the late 1980s, computed tomography (CT) has become the basis for modern radiation treatment planning and delivery, coincident with the rise of 3-dimensional conformal radiation therapy (3DCRT). Additionally, multi-modality anatomic imaging registration was the solution pursued to augment delineation of tumors and surrounding structures on CT-based treatment planning. Although these imaging modalities provide the customary anatomic details necessary for radiation treatment planning, they have limitations, including difficulty with identification of small tumor deposits, tumor extension, and distinction from scar tissues. To overcome these limitations, PET and, more recently, PET-CT have been innovative regarding the extent of disease appraisal, target delineation in the treatment planning, and assessment of therapy response. We review the role of functional imaging in IGRT as it reassures transformations on the field of radiation oncology. As we move toward the era of IGRT, the use of multi-modality imaging fusion, and the introduction of more sensitive and specific PET-CT tracers may further assist target definition. Furthermore, the potential to predict early outcome or even detect early recurrence of tumor, may allow for the tailoring of intervention in cancer patients. The convergence of a biological target volume, and perhaps multi-tracer tumor, molecular, and genetic profile tumors will probably be vital in cancer treatment selection. Nevertheless, prospective clinical experience with outcome is encouraged and needs to be expanded to entirely exploit the benefits of the IGRT.

Humans↗
PubMed2006

Does breast size affect the scatter dose to the ipsilateral lung, heart, or contralateral breast in primary breast irradiation using intensity-modulated radiation therapy (IMRT)?

PURPOSE: To evaluate the relationship between the primary breast volume and dose received by the ipsilateral lung, heart (for left-breast cancers), and contralateral breast during primary breast irradiation using intensity-modulated radiation therapy (IMRT). METHODS AND MATERIALS: Sixty-five patients with breast carcinoma were treated using 6-MV photons with IMRT technique using the Eclipse Planning System following breast conserving surgery. All patients had a treatment planning CT scan. The primary breast, ipsilateral lung, and heart were contoured on the axial CT slices. The primary breast volume was calculated using the Eclipse Planning System. The mean ipsilateral lung and heart doses were obtained from the dose-volume histogram. The contralateral breast dose was measured using paired thermoluminescent dosimeters (TLDs) placed on the patient's contralateral breast, 4 cm from the center of the medial border of the primary breast irradiation field. RESULTS: The mean dose delivered with photons to the primary breast for all patients was 49.97 Gy. The mean volume of the primary irradiated breast was 1167.9 cc. As a percentage, the mean ipsilateral lung, heart, and contralateral breast doses were 11.2%, 6.1%, and 7.2%, respectively. The primary breast volume positively correlated with the contralateral breast dose (P < 0.0005). There was no significant correlation between the breast volume and the ipsilateral lung or heart dose (P = 0.463 and 0.943, respectively). CONCLUSION: This study suggests that the primary breast size significantly affects the scatter dose to the contralateral breast but not the ipsilateral lung or heart dose when using IMRT for breast irradiation.

Breast↗
PubMed2006

The potential nephrotoxic effects of intensity modulated radiotherapy delivered to the para-aortic area of women with gynecologic malignancies: preliminary results.

OBJECTIVE: To assess kidney function via creatinine clearance before and after radiotherapy in gynecologic cancer patients treated to the para-aortic (PA) area via Intensity Modulated Radiotherapy (IMRT). METHODS: Twenty-three patients underwent IMRT to the para-aortic area, were followed for at least 5 months, and had the necessary laboratory data to calculate creatinine clearance. Various patient-related factors and radiotherapy-treatment related factors were analyzed to determine their association with changes in CrCl. RESULTS: Median follow-up was 10.9 months (range, 5-19 months). Median patient age was 51.7 years (range, 22-78). The average initial CrCl was noted to be 109.23 mL/min (range, 38.64-188.38) before radiotherapy and decreased to 90.00 mL/min (29.31-175.61) after radiotherapy (P = 0.004). Although 17 patients had a decrease in their CrCl, 6 were found to have a slight elevation. Five factors were associated with a decrement in CrCl greater than the average decrease (17.6%): presence of hydronephrosis, age <50, no history of cisplatin treatment, a BED to gross adenopathy exceeding mean BED, and salvage treatment of PA node recurrence. Subgroup analysis revealed that the only statistically significant change within the group of patient and/or treatment-related factors was between patients who were <50-year-old and patients who were > or =50 years of age (P = 0.03). No patient exhibited clinical signs of radiation-induced nephropathy. CONCLUSION: With a median follow-up of 10.9 months, the estimated CrCl decreased by 17.6% after IMRT to the para-aortic area +/- cisplatin chemotherapy. The greatest decrease in CrCl occurred in patients who had a history of hydronephrosis. Subgroup analysis revealed that the decline in CrCl was significantly greater for patients younger than 50 years of age. Interestingly, a greater decline in CrCl was noted for those patients who did not have a history of cisplatin treatment. Our preliminary results indicate that IMRT +/- cisplatin chemotherapy to the para-aortic area of women is safe and is not associated with any clinical sequelae of renal toxicity despite a small decrement in CrCl in most, but not all patients.

Adult↗
PubMed2006

Comparison of 2D vs. 3D dosimetry for Rotte 'Y' applicator high dose rate brachytherapy for medically inoperable endometrial cancer.

The purpose of our research is to compare CT-based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the target volume, bladder, rectum, and sigmoid colon in patients with carcinoma of the endometrium treated with high dose rate intracavitary Rotte 'Y' applicator brachytherapy (HDRB). Eleven patients with cancer of the endometrium were treated with CT-compatible HDR intracavitary Rotte 'Y' applicators (Nucletron) and underwent post-implant pelvic CT scans with applicators in place. All patients were treated using orthogonal radiography-based planning. The dose was prescribed to uterine point (a point located 2 cm below the center of a line drawn between the tips of the two ends of the Rotte applicator extending laterally from the tandem by half the maximum uterine width), Point A, and 0.5 cm depth along the upper 3 cm vagina. CT-images were transferred to the PLATO treatment planning system version 14.2.6 and retrospectively planned for volumetric calculations. The clinical target volume (CTV) included the entire uterus, cervix, and upper 3 cm of vagina. The volumes of organs at risk (OAR) were digitized. Dwell positions were identified and registered in both the uterine tandem for each patient. For those receiving HDRB alone, the prescribed dose was 7 Gy x 5 fractions. Patients who were treated following external beam radiation therapy (EBRT) received 4 Gy x 5 fractions. The interfraction interval was 6-8 hours. The DVHs were computed for the CTV, bladder, rectum, and sigmoid colon. To compare doses of OARs, 1.0 cc, 2.0 cc, and 5.0 cc volumes receiving the highest dose were calculated from DVHs. 3D optimization was done to improve target coverage and decrease dose to critical organs and compared with the 2D orthogonal radiograph-based plan. The mean of percentage of prescribed dose +/- S.D to 1 cc, 2 cc, and 5 cc of the OARs of interest were as follows: Rectum 44 +/- 21%, 39 +/- 18%, and 33 +/- 15%; bladder 104 +/- 36%, 91 +/- 31%, and 73.9 +/- 24%; and sigmoid 124 +/- 35%, 109 +/- 30%, and 89 +/- 25%, respectively. The corresponding dose to ICRU 38 bladder and rectal points were 98 +/- 55% and 50.5 +/- 32%, respectively. The mean dose to uterine point and point A were 99 +/- 1.7% and 98 +/- 3%, respectively. The mean CTV volume was 160 +/- 89 cc with the percentage of volume getting 100% and 90% of the dose being 62 +/- 12% and 68 +/- 12% with 2D plan versus 57 +/- 8% and 67 +/- 8.9% with 3D plan. The dose to critical organs were reduced with 3D optimization for rectum, bladder, and sigmoid by 5.6% (p = 0.04), 20.6% (p = 0.02), and 26.8% (p = 0.005), respectively. Compared to the 3-D volume dose, the prescription points overestimated the dose to the target volume. The under-dosing was because of inability of two channel applicator to cover volumes in the region of the cervix and vagina. The dose to sigmoid colon was high and attention should be given to the sigmoid dose at the time of treatment planning. 3D planning helped in reducing the dose to the critical organs without compromising target coverage. Correlations with outcome are needed to better define the role of 3D dosimetry in treatment planning.

Brachytherapy↗
PubMed2006

Frameless stereotactic radiosurgery for recurrent head and neck carcinoma.

The aim of this study was to assess the feasibility and toxicity of stereotactic radiosurgery (CK-SRS) using the CyberKnife Frameless Radiosurgery System (Accuray Inc., Sunnyvale, CA) in the management of recurrent squamous cell carcinoma of the head and neck region (SCCHN). Between November 2001 and February 2004, 22 patients with recurrent, previously irradiated SCCHN were treated with CK-SRS. The following endpoints were assessed post-CK-SRS: local control (LC), cause-specific survival (CSS), overall survival (OS), symptom relief, and acute and late toxicity. Kaplan-Meier survival analyses were used to estimate the LC, CSS, and OS rates. Clinical symptoms were graded as "improved," "stable," or "progressed" after CK-SRS. Acute and late toxicity were graded according to the National Cancer Institute Common Toxicity Criteria (CTC) scale, version 2.0. Seventeen patients were followed until their death. The median follow-up in the remaining five patients was 19 months (range 11-40 months). The median survival time for the entire cohort was 12 months from the time of CK-SRS. The 2-year LC, CSS, and OS rates were 26%, 26%, and 22%, respectively. After CK-SRS, symptoms were improved or stable in all but one patient who reported increasing pain. The treatment was well tolerated, with one case each of Grade 2 and 3 mucositis. There were no acute Grade 4 or 5 CTC toxicities. There were no late toxicities in this cohort. Frameless stereotactic radiosurgery for recurrent SCCHN is feasible and safe in the setting of high doses of prior irradiation. The majority of patients experienced palliation of disease without excess toxicity.

Adult↗
PubMed2005

A dose verification method using a monitor unit matrix for dynamic IMRT on Varian linear accelerators.

Dosimetry verification is an important step during intensity modulated radiotherapy treatment (IMRT). The verification is usually conducted with measurements and independent dose calculations. However, currently available independent dose calculation methods were developed for step-and-shoot beam delivery methods, and their uses for dynamic multi-leaf collimator (MLC) delivery methods are not efficient. In this study, a dose calculation method was developed to perform independent dose verifications for a dynamic MLC-based IMRT technique for Varian linear accelerators. This method extracts the machine delivery parameters from the dynamic MLC (DMLC) files generated by the IMRT treatment planning system. Based on the parameters a monitor unit (MU) matrix was separately calculated as two terms: direct exposure from the open MLC field and leakage contributions, where the leaf-end leakage contribution becomes more important in higher dose gradient regions. The MU matrix was used to compute the primary dose and the scattered dose with a modified Clarkson technique. The doses computed using the method were compared with both measurement and treatment planning for 14 and 25 plans respectively. An average of less than 2% agreement was observed and the standard deviation was about 1.9%.

Algorithms↗
PubMed2005

Intensity modulated radiation therapy (IMRT) reduces the dose to the contralateral breast when compared to conventional tangential fields for primary breast irradiation.

PURPOSE: To determine the dose received by the contralateral breast during primary breast irradiation using IMRT compared to conventional tangential field techniques. METHODS AND MATERIALS: Between March 2003 and March 2004, 83 patients with breast carcinoma were treated using 6, 10, or mixed 6/18 MV photons (65 with tangential IMRT technique and 18 with 3-dimensional technique using tangential fields with wedges) for primary breast irradiation following breast-conserving surgery. Paired thermoluminescent dosimeters (TLDs) were placed on each patient's contralateral breast, 4 and 8 cm from the center of the medial border of the tangential field. The TLDs were left on the patient during a single fraction and then measured 24 h afterwards. RESULTS: The mean dose delivered with photons to the primary breast for all patients was 4999 cGy (SD = 52) with a mean single fraction dose of 199 cGy (SD = 8). The mean percent of the prescribed dose to the contralateral breast measured at the 4- and 8-cm positions were 7.19% (SD = 2.28) and 4.63% (SD = 2.12), respectively, for patients treated with IMRT compared to 11.22% (SD = 2.73) and 10.70% (SD = 3.44), respectively, for the patients treated with conventional tangential field techniques. This represented a 36% and 57% reduction at the 4 and 8-cm contralateral positions, respectively, in the mean dose to the contralateral breast using IMRT compared to 3-D technique which was statistically significant (p < 0.0005, <0.0005, respectively). CONCLUSION: Primary breast irradiation with tangential IMRT technique significantly reduces the dose to the contralateral breast compared to conventional tangential field techniques.

Breast↗