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ABSTRACT: Purpose: The delivery of post-mastectomy radiation therapy (PMRT) can be challenging for patients with left sided breast cancer that have undergone mastectomy. This study investigates the use of protons for PMRT in selected patients with unfavorable cardiac anatomy. We also report the first clinical application of protons for these patients.Methods and materials: Eleven patients were planned with protons, partially wide tangent photon fields (PWTF), and photon/electron (P/E) fields. Plans were generated with the goal of achieving 95% coverage of target volumes while maximally sparing cardiac and pulmonary structures. In addition, we report on two patients with unfavorable cardiac anatomy and IMN involvement that were treated with a mix of proton and standard radiation. RESULTS: PWTF, P/E, and proton plans were generated and compared. Reasonable target volume coverage was achieved with PWTF and P/E fields, but proton therapy achieved superior coverage with a more homogeneous plan. Substantial cardiac and pulmonary sparing was achieved with proton therapy as compared to PWTF and P/E. In the two clinical cases, the delivery of proton radiation with a 7.2 to 9 Gy photon and electron component was feasible and well tolerated. Akimbo positioning was necessary for gantry clearance for one patient; the other was treated on a breast board with standard positioning (arms above her head). LAO field arrangement was used for both patients. Erythema and fatigue were the only noted side effects. CONCLUSIONS: Proton RT enables delivery of radiation to the chest wall and regional lymphatics, including the IMN, without compromise of coverage and with improved sparing of surrounding normal structures. This treatment is feasible, however, optimal patient set up may vary and field size is limited without multiple fields/matching.
Radiation Oncology 03/2013; 8(1):71. · 2.32 Impact Factor
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Shannon M Macdonald,
Sagar A Patel,
Shea Hickey,
Michelle Specht,
Steven J Isakoff,
Michele Gadd,
Barbara L Smith,
Beow Y Yeap, Judith Adams,
Thomas F Delaney,
Hanne Kooy,
Hsiao-Ming Lu,
Alphonse G Taghian
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ABSTRACT: PURPOSE: Dosimetric planning studies have described potential benefits for the use of proton radiation therapy (RT) for locally advanced breast cancer. We report acute toxicities and feasibility of proton delivery for 12 women treated with postmastectomy proton radiation with or without reconstruction. METHODS AND MATERIALS: Twelve patients were enrolled in an institutional review board-approved prospective clinical trial. The patients were assessed for skin toxicity, fatigue, and radiation pneumonitis during treatment and at 4 and 8 weeks after the completion of therapy. All patients consented to have photographs taken for documentation of skin toxicity. RESULTS: Eleven of 12 patients had left-sided breast cancer. One patient was treated for right-sided breast cancer with bilateral implants. Five women had permanent implants at the time of RT, and 7 did not have immediate reconstruction. All patients completed proton RT to a dose of 50.4 Gy (relative biological effectiveness [RBE]) to the chest wall and 45 to 50.4 Gy (RBE) to the regional lymphatics. No photon or electron component was used. The maximum skin toxicity during radiation was grade 2, according to the Common Terminology Criteria for Adverse Events (CTCAE). The maximum CTCAE fatigue was grade 3. There have been no cases of RT pneumonitis to date. CONCLUSIONS: Proton RT for postmastectomy RT is feasible and well tolerated. This treatment may be warranted for selected patients with unfavorable cardiac anatomy, immediate reconstruction, or both that otherwise limits optimal RT delivery using standard methods.
International journal of radiation oncology, biology, physics 03/2013; · 4.59 Impact Factor
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ABSTRACT: To calculated projected second tumor rates and dose to organs at risk (OAR) in patients with benign intracranial meningioma (BM), according to dosimetric comparisons between proton radiotherapy (PRT) and photon radiotherapy (XRT) treatment plans.
Ten patients with BM treated at Massachusetts General Hospital during 2006-2010 with PRT were replanned with XRT (intensity-modulated or three-dimensional conformal radiotherapy), optimizing dose to the tumor while sparing OAR. Total dose was 54 Gy in 1.8 Gy per fraction for all plans. We calculated equivalent uniform doses, normal tissue complication probabilities, and whole brain-based estimates of excess risk of radiation-associated intracranial second tumors.
Excess risk of second tumors was significantly lower among PRT compared with XRT plans (1.3 vs. 2.8 per 10,000 patients per year, p < 0.002). Mean equivalent uniform doses were lower among PRT plans for the whole brain (19.0 vs. 22.8 Gy, p < 0.0001), brainstem (23.8 vs. 35.2 Gy, p = 0.004), hippocampi (left, 13.5 vs. 25.6 Gy, p < 0.0001; right, 7.6 vs. 21.8 Gy, p = 0.001), temporal lobes (left, 25.8 vs. 34.6 Gy, p = 0.007; right, 25.8 vs. 32.9 Gy, p = 0.008), pituitary gland (29.2 vs. 37.0 Gy, p = 0.047), optic nerves (left, 28.5 vs. 33.8 Gy, p = 0.04; right, 25.1 vs. 31.1 Gy, p = 0.07), and cochleas (left, 12.2 vs. 15.8 Gy, p = 0.39; right,1.5 vs. 8.8 Gy, p = 0.01). Mean normal tissue complication probability was <1% for all structures and not significantly different between PRT and XRT plans.
Compared with XRT, PRT for BM decreases the risk of RT-associated second tumors by half and delivers significantly lower doses to neurocognitive and critical structures of vision and hearing.
International journal of radiation oncology, biology, physics 01/2012; 83(4):e495-500. · 4.59 Impact Factor
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ABSTRACT: Proton beam radiotherapy has been proposed for use in stereotactic body radiotherapy (SBRT) for early-stage non-small-cell lung cancer. In the present study, we sought to analyze how the range uncertainties for protons might affect its therapeutic utility for SBRT.
Ten patients with early-stage non-small-cell lung cancer received SBRT with two to three proton beams. The patients underwent repeat planning for photon SBRT, and the dose distributions to the normal and tumor tissues were compared with the proton plans. The dosimetric comparisons were performed within an operational definition of high- and low-dose regions representing volumes receiving >50% and <50% of the prescription dose, respectively.
In high-dose regions, the average volume receiving ≥95% of the prescription dose was larger for proton than for photon SBRT (i.e., 46.5 cm(3) vs. 33.5 cm(3); p = .009, respectively). The corresponding conformity indexes were 2.46 and 1.56. For tumors in close proximity to the chest wall, the chest wall volume receiving ≥30 Gy was 7 cm(3) larger for protons than for photons (p = .06). In low-dose regions, the lung volume receiving ≥5 Gy and maximum esophagus dose were smaller for protons than for photons (p = .019 and p < .001, respectively).
Protons generate larger high-dose regions than photons because of range uncertainties. This can result in nearby healthy organs (e.g., chest wall) receiving close to the prescription dose, at least when two to three beams are used, such as in our study. Therefore, future research should explore the benefit of using more than three beams to reduce the dose to nearby organs. Additionally, clinical subgroups should be identified that will benefit from proton SBRT.
International journal of radiation oncology, biology, physics 10/2011; 83(1):354-61. · 4.59 Impact Factor
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ABSTRACT: To report the clinical outcome and late side effect profile of proton radiotherapy in the treatment of children with parameningeal rhabdomyosarcoma (PM-RMS).
Seventeen consecutive children with PM-RMS were treated with proton radiotherapy at Massachusetts General Hospital between 1996 and 2005. We reviewed the medical records of all patients and asked referring physicians to report specific side effects of interest.
Median patient age at diagnosis was 3.4 years (range, 0.4-17.6). Embryonal (n = 11), alveolar (n = 4), and undifferentiated (n = 2) histologies were represented. Ten patients (59%) had intracranial extension. Median prescribed dose was 50.4 cobalt gray equivalents (GyRBE) (range, 50.4-56.0 GyRBE) delivered in 1.8-2.0-GyRBE daily fractions. Median follow-up was 5.0 years for survivors. The 5-year failure-free survival estimate was 59% (95% confidence interval, 33-79%), and overall survival estimate was 64% (95% confidence interval, 37-82%). Among the 7 patients who failed, sites of first recurrence were local only (n = 2), regional only (n = 2), distant only (n = 2), and local and distant (n = 1). Late effects related to proton radiotherapy in the 10 recurrence-free patients (median follow-up, 5 years) include failure to maintain height velocity (n = 3), endocrinopathies (n = 2), mild facial hypoplasia (n = 7), failure of permanent tooth eruption (n = 3), dental caries (n = 5), and chronic nasal/sinus congestion (n = 2).
Proton radiotherapy for patients with PM-RMS yields tumor control and survival comparable to that in historical controls with similar poor prognostic factors. Furthermore, rates of late effects from proton radiotherapy compare favorably to published reports of photon-treated cohorts.
International journal of radiation oncology, biology, physics 03/2011; 82(2):635-42. · 4.59 Impact Factor
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Theodore S Hong,
David P Ryan,
Lawrence S Blaszkowsky,
Harvey J Mamon,
Eunice L Kwak,
Mari Mino-Kenudson, Judith Adams,
Beow Yeap,
Barbara Winrich,
Thomas F DeLaney,
Carlos Fernandez-Del Castillo
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ABSTRACT: To evaluate the safety of 1 week of chemoradiation with proton beam therapy and capecitabine followed by early surgery.
Fifteen patients with localized resectable, pancreatic adenocarcinoma of the head were enrolled from May 2006 to September 2008. Patients received radiation with proton beam. In dose level 1, patients received 3 GyE × 10 (Week 1, Monday-Friday; Week 2, Monday-Friday). Patients in Dose Levels 2 to 4 received 5 GyE × 5 in progressively shortened schedules: level 2 (Week 1, Monday, Wednesday, and Friday; Week 2, Tuesday and Thursday), Level 3 (Week 1, Monday, Tuesday, Thursday, and Friday; Week 2, Monday), Level 4 (Week 1, Monday through Friday). Capecitabine was given as 825 mg/m(2) b.i.d. Weeks 1 and 2 Monday through Friday for a total of 10 days in all dose levels. Surgery was performed 4 to 6 weeks after completion of chemotherapy for Dose Levels 1 to 3 and then after 1 to 3 weeks for Dose Level 4.
Three patients were treated at Dose Levels 1 to 3 and 6 patients at Dose Level 4, which was selected as the MTD. No dose limiting toxicities were observed. Grade 3 toxicity was noted in 4 patients (pain in 1; stent obstruction or infection in 3). Eleven patients underwent resection. Reasons for no resection were metastatic disease (3 patients) and unresectable tumor (1 patient). Mean postsurgical length of stay was 6 days (range, 5-10 days). No unexpected 30-day postoperative complications, including leak or obstruction, were found.
Preoperative chemoradiation with 1 week of proton beam therapy and capecitabine followed by early surgery is feasible. A Phase II study is underway.
International journal of radiation oncology, biology, physics 01/2011; 79(1):151-7. · 4.59 Impact Factor
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ABSTRACT: In this study, we report the clinical outcomes of 7 children with bladder/prostate rhabdomyosarcoma (RMS) treated with proton radiation and compare proton treatment plans with matched intensity-modulated radiation therapy (IMRT) plans, with an emphasis on dose savings to reproductive and skeletal structures.
Follow-up consisted of scheduled clinic appointments at our institution or direct communication with the treating physicians for referred patients. Each proton radiotherapy plan used for treatment was directly compared to an IMRT plan generated for the study. Clinical target volumes and normal tissue volumes were held constant to facilitate dosimetric comparisons. Each plan was optimized for target coverage and normal tissue sparing.
Seven male patients were treated with proton radiotherapy for bladder/prostate RMS at the Massachusetts General Hospital between 2002 and 2008. Median age at treatment was 30 months (11-70 months). Median follow-up was 27 months (10-90 months). Four patients underwent a gross total resection prior to radiation, and all patients received concurrent chemotherapy. Radiation doses ranged from 36 cobalt Gray equivalent (CGE) to 50.4 CGE. Five of 7 patients were without evidence of disease and with intact bladders at study completion. Target volume dosimetry was equivalent between the two modalities for all 7 patients. Proton radiotherapy led to a significant decrease in mean organ dose to the bladder (25.1 CGE vs. 33.2 Gy; p=0.03), testes (0.0 CGE vs. 0.6 Gy; p=0.016), femoral heads (1.6 CGE vs. 10.6 Gy; p=0.016), growth plates (21.7 CGE vs. 32.4 Gy; p=0.016), and pelvic bones (8.8 CGE vs. 13.5 Gy; p=0.016) compared to IMRT.
This study provides evidence of significant dose savings to normal structures with proton radiotherapy compared to IMRT and is well tolerated in this patient population. The long-term impact of these reduced doses can be tested in future studies incorporating extended follow-up, objective outcome measures, and quality-of-life analyses.
International journal of radiation oncology, biology, physics 10/2010; 81(5):1367-73. · 4.59 Impact Factor
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ABSTRACT: To report early clinical outcomes for children with central nervous system (CNS) germ cell tumors treated with protons; to compare dose distributions for intensity-modulated photon radiotherapy (IMRT), three-dimensional conformal proton radiation (3D-CPT), and intensity-modulated proton therapy with pencil beam scanning (IMPT) for whole-ventricular irradiation with and without an involved-field boost.
All children with CNS germinoma or nongerminomatous germ cell tumor who received treatment at the Massachusetts General Hospital between 1998 and 2007 were included in this study. The IMRT, 3D-CPT, and IMPT plans were generated and compared for a representative case.
Twenty-two patients were treated with 3D-CPT. At a median follow-up of 28 months, there were no CNS recurrences; 1 patient had a recurrence outside the CNS. Local control, progression-free survival, and overall survival rates were 100%, 95%, and 100%, respectively. Comparable tumor volume coverage was achieved with IMRT, 3D-CPT, and IMPT. Substantial normal tissue sparing was seen with any form of proton therapy as compared with IMRT. The use of IMPT may yield additional sparing of the brain and temporal lobes.
Preliminary disease control with proton therapy compares favorably to the literature. Dosimetric comparisons demonstrate the advantage of proton radiation over IMRT for whole-ventricle radiation. Superior dose distributions were accomplished with fewer beam angles utilizing 3D-CPT and scanned protons. Intensity-modulated proton therapy with pencil beam scanning may improve dose distribution as compared with 3D-CPT for this treatment.
International journal of radiation oncology, biology, physics 05/2010; 79(1):121-9. · 4.59 Impact Factor
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Thomas F DeLaney,
Norbert J Liebsch,
Francis X Pedlow, Judith Adams,
Susan Dean,
Beow Y Yeap,
Patricia McManus,
Andrew E Rosenberg,
G Petur Nielsen,
David C Harmon,
Ira J Spiro,
Kevin A Raskin,
Herman D Suit,
Sam S Yoon,
Francis J Hornicek
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ABSTRACT: Radiotherapy (XRT) for spine sarcomas is constrained by spinal cord, nerve, and viscera tolerance. Negative surgical margins are uncommon; hence, doses of >or=66 Gy are recommended. A Phase II clinical trial evaluated high-dose photon/proton XRT for spine sarcomas.
Eligible patients had nonmetastatic, thoracic, lumbar, and/or sacral spine/paraspinal sarcomas. Treatment included pre- and/or postoperative photon/proton XRT with or without radical resection; patients with osteosarcoma and Ewing's sarcoma received chemotherapy. Shrinking fields delivered 50.4 cobalt Gray equivalent (Gy RBE) to subclinical disease, 70.2 Gy RBE to microscopic disease in the tumor bed, and 77.4 Gy RBE to gross disease at 1.8 Gy RBE qd. Doses were reduced for radiosensitive histologies, concurrent chemoradiation, or when diabetes or autoimmune disease present. Spinal cord dose was limited to 63/54 Gy RBE to surface/center. Intraoperative boost doses of 7.5 to 10 Gy could be given by dural plaque.
A total of 50 patients (29 chordoma, 14 chondrosarcoma, 7 other) underwent gross total (n = 25) or subtotal (n = 12) resection or biopsy (n = 13). With 48 month median follow-up, 5-year actuarial local control, recurrence-free survival, and overall survival are: 78%, 63%, and 87% respectively. Two of 36 (5.6%) patients treated for primary versus 7/14 (50%) for recurrent tumor developed local recurrence (p < 0.001). Five patients developed late radiation-associated complications; no myelopathy developed but three sacral neuropathies appeared after 77.12 to 77.4 Gy RBE.
Local control with this treatment is high in patients radiated at the time of primary presentation. Spinal cord dose constraints appear to be safe. Sacral nerves receiving 77.12-77.4 Gy RBE are at risk for late toxicity.
International journal of radiation oncology, biology, physics 01/2009; 74(3):732-9. · 4.59 Impact Factor
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ABSTRACT: We compared tumor and normal tissue dosimetry of proton radiation therapy with intensity-modulated radiation therapy (IMRT) for pediatric parameningeal rhabdomyosarcomas (PRMS).
To quantify dosimetric differences between contemporary proton and photon treatment for pediatric PRMS, proton beam plans were compared with IMRT plans. Ten patients treated with proton radiation therapy at Massachusetts General Hospital had IMRT plans generated. To facilitate dosimetric comparisons, clinical target volumes and normal tissue volumes were held constant. Plans were optimized for target volume coverage and normal tissue sparing.
Proton and IMRT plans provided acceptable and comparable target volume coverage, with at least 99% of the CTV receiving 95% of the prescribed dose in all cases. Improved dose conformality provided by proton therapy resulted in significant sparing of all examined normal tissues except for ipsilateral cochlea and mastoid; ipsilateral parotid gland sparing was of borderline statistical significance (p = 0.05). More profound sparing of contralateral structures by protons resulted in greater dose asymmetry between ipsilateral and contralateral retina, optic nerves, cochlea, and mastoids; dose asymmetry between ipsilateral and contralateral parotids was of borderline statistical significance (p = 0.05).
For pediatric PRMS, superior normal tissue sparing is achieved with proton radiation therapy compared with IMRT. Because of enhanced conformality, proton plans also demonstrate greater normal tissue dose distribution asymmetry. Longitudinal studies assessing the impact of proton radiotherapy and IMRT on normal tissue function and growth symmetry are necessary to define the clinical consequences of these differences.
International journal of radiation oncology, biology, physics 12/2008; 74(1):179-86. · 4.59 Impact Factor
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ABSTRACT: To evaluate tumor and normal tissue dosimetry of a 5 cobalt gray equivalent (CGE) x 5 fraction proton radiotherapy schedule, before initiating a clinical trial of neoadjuvant, short-course proton radiotherapy for pancreatic adenocarcinoma.
The first 9 pancreatic cancer patients treated with neoadjuvant intensity-modulated radiotherapy (1.8 Gy x 28) at the Massachusetts General Hospital had treatment plans generated using a 5 CGE x 5 fraction proton regimen. To facilitate dosimetric comparisons, clinical target volumes and normal tissue volumes were held constant. Plans were optimized for target volume coverage and normal tissue sparing.
Hypofractionated proton and conventionally fractionated intensity-modulated radiotherapy plans both provided acceptable target volume coverage and dose homogeneity. Improved dose conformality provided by the hypofractionated proton regimen resulted in significant sparing of kidneys, liver, and small bowel, evidenced by significant reductions in the mean doses, expressed as percentage prescribed dose, to these structures. Kidney and liver sparing was most evident in low-dose regions (< or =20% prescribed dose for both kidneys and < or =60% prescribed dose for liver). Improvements in small-bowel dosimetry were observed in high- and low-dose regions. Mean stomach and duodenum doses, expressed as percentage prescribed dose, were similar for the two techniques.
A proton radiotherapy schedule consisting of 5 fractions of 5 CGE as part of neoadjuvant therapy for adenocarcinoma of the pancreas seems dosimetrically feasible, providing excellent target volume coverage, dose homogeneity, and normal tissue sparing. Hypofractionated proton radiotherapy in this setting merits Phase I clinical trial investigation.
International Journal of Radiation OncologyBiologyPhysics 09/2007; 68(5):1557-66. · 4.11 Impact Factor
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Kevin R Kozak,
Barbara L Smith, Judith Adams,
Ellen Kornmehl,
Angela Katz,
Michele Gadd,
Michelle Specht,
Kevin Hughes,
Valeria Gioioso,
Hsiao-Ming Lu,
Kristina Braaten,
Abram Recht,
Simon N Powell,
Thomas F DeLaney,
Alphonse G Taghian
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ABSTRACT: We present our initial clinical experience with proton, three-dimensional, conformal, external beam, partial-breast irradiation (3D-CPBI).
Twenty patients with Stage I breast cancer were treated with proton 3D-CPBI in a Phase I/II clinical trial. Patients were followed at 3 to 4 weeks, 6 to 8 weeks, 6 months, and every 6 months thereafter for recurrent disease, cosmetic outcome, toxicity, and patient satisfaction.
With a median follow-up of 12 months (range, 8-22 months), no recurrent disease has been detected. Global breast cosmesis was judged by physicians to be good or excellent in 89% and 100% of cases at 6 months and 12 months, respectively. Patients rated global breast cosmesis as good or excellent in 100% of cases at both 6 and 12 months. Proton 3D-CPBI produced significant acute skin toxicity with moderate to severe skin color changes in 79% of patients at 3 to 4 weeks and moderate to severe moist desquamation in 22% of patients at 6 to 8 weeks. Telangiectasia was noted in 3 patients. Three patients reported rib tenderness in the treated area, and one rib fracture was documented. At last follow-up, 95% of patients reported total satisfaction with proton 3D-CPBI.
Based on our study results, proton 3D-CPBI offers good-to-excellent cosmetic outcomes in 89% to 100% of patients at 6-month and 12-month follow-up and nearly universal patient satisfaction. However, proton 3D-CPBI, as used in this study, does result in significant acute skin toxicity and may potentially be associated with late skin (telangiectasia) and rib toxicity. Because of the dosimetric advantages of proton 3D-CPBI, technique modifications are being explored to improve acute skin tolerance.
International Journal of Radiation OncologyBiologyPhysics 12/2006; 66(3):691-8. · 4.11 Impact Factor
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ABSTRACT: To compare the dosimetry of proton and photon-electron three-dimensional, conformal, external beam accelerated partial breast irradiation (3D-CPBI).
Twenty-four patients with fully excised, Stage I breast cancer treated with adjuvant proton 3D-CPBI had treatment plans generated using the mixed-modality, photon-electron 3D-CPBI technique. To facilitate dosimetric comparisons, planning target volumes (PTVs; lumpectomy site plus 1.5-2.0 cm margin) and prescribed dose (32 Gy) were held constant. Plans were optimized for PTV coverage and normal tissue sparing.
Proton and mixed-modality plans both provided acceptable PTV coverage with 95% of the PTV receiving 90% of the prescribed dose in all cases. Both techniques also provided excellent dose homogeneity with a dose maximum exceeding 110% of the prescribed dose in only one case. Proton 3D-CPBI reduced the volume of nontarget breast tissue receiving 50% of the prescribed dose by an average of 36%. Statistically significant reductions in the volume of total ipsilateral breast receiving 100%, 75%, 50%, and 25% of the prescribed dose were also observed. The use of protons resulted in small, but statistically significant, reductions in the radiation dose delivered to 5%, 10%, and 20% of ipsilateral and contralateral lung and heart. The nontarget breast tissue dosimetric advantages of proton 3D-CPBI were not dependent on tumor location, breast size, PTV size, or the ratio of PTV to breast volume.
Compared to photon-electron 3D-CPBI, proton 3D-CPBI significantly reduces the volume of irradiated nontarget breast tissue. Both approaches to accelerated partial breast irradiation offer exceptional lung and heart sparing.
International Journal of Radiation OncologyBiologyPhysics 09/2006; 65(5):1572-8. · 4.11 Impact Factor
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ABSTRACT: The unique dosimetric features of proton radiotherapy make it an attractive modality for normal tissue sparing. We present our initial experience with protons for three-dimensional, conformal, external-beam accelerated partial breast irradiation (3D-CPBI).
From March 2004 to June 2005, 25 patients with tumors < or =2 cm and negative axillary nodes were treated with proton 3D-CPBI. The prescribed dose was 32 Cobalt Gray Equivalents (CGE) in 4 CGE fractions given twice daily. One to three fields were used to provide adequate planning target volume (PTV) coverage and dose homogeneity.
Excellent PTV coverage and dose homogeneity were obtained in all patients with one to three proton beams. The median PTV receiving 95% of the prescribed dose was 100%. Dose inhomogeneity exceeded 10% in only 1 patient (4%). The median volume of nontarget breast tissue receiving 50% of the prescribed dose was 23%. Median volumes of ipsilateral lung receiving 20 CGE, 10 CGE, and 5 CGE were 0%, 1%, and 2%, respectively. The contralateral lung and heart received essentially no radiation dose. Cost analysis suggests that proton 3D-CPBI is only modestly more expensive (25%) than traditional whole-breast irradiation (WBI).
Proton 3D-CPBI is technically feasible, providing both excellent PTV coverage and normal tissue sparing. It markedly reduces the volume of nontarget breast tissue irradiated compared with photon-based 3D-CPBI, addressing a principle disadvantage of external-beam approaches to PBI. As proton therapy becomes more widely available, it may prove an attractive tool for 3D-CPBI.
International Journal of Radiation OncologyBiologyPhysics 08/2006; 65(5):1404-10. · 4.11 Impact Factor
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ABSTRACT: Over 85% of pediatric orbital rhabdomyosarcoma (RMS) are cured with combined chemotherapy and radiation. However, the late effects of photon radiation compromise function and cosmetic outcome. Proton radiation can provide excellent tumor dose distributions while sparing normal tissues better than photon irradiation.
Conformal 3D photon and proton radiotherapy plans were generated for children treated with proton irradiation for orbital RMS at Massachusetts General Hospital. Dose-volume histograms (90%, 50%, 10%) were generated and compared for important orbital and central nervous system structures. Average percentages of total dose prescribed were calculated based on the 3 dose-volume histogram levels for normal orbital structures for both the proton and photon plans. The percent of normal tissue spared by using protons was calculated.
Seven children were treated for orbital rhabdomyosarcoma with proton irradiation and standard chemotherapy. The median follow-up is 6.3 years (range, 3.5-9.7 years). Local and distant controls compare favorably to those in other published accounts. There was an advantage in limiting the dose to the brain, pituitary, hypothalamus, temporal lobes, and ipsilateral and contralateral orbital structures. Tumor size and location affect the degree of sparing of normal structures.
Fractionated proton radiotherapy is superior to 3D conformal photon radiation in the treatment of orbital RMS. Proton therapy maintains excellent tumor coverage while reducing the radiation dose to adjacent normal structures. Proton radiation therapy minimizes long-term side effects.
International Journal of Radiation OncologyBiologyPhysics 12/2005; 63(4):1161-8. · 4.11 Impact Factor
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Herman Suit,
Saveli Goldberg,
Andrzej Niemierko,
Alexei Trofimov, Judith Adams,
Harald Paganetti,
George T Y Chen,
Thomas Bortfeld,
Stanley Rosenthal,
Jay Loeffler,
Thomas Delaney
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ABSTRACT: With proton beam radiation therapy a smaller volume of normal tissues is irradiated at high dose levels for most anatomic sites than is feasible with any photon technique. This is due to the Laws of Physics, which determine the absorption of energy from photons and protons. In other words, the dose from a photon beam decreases exponentially with depth in the irradiated material. In contrast, protons have a finite range and that range is energy dependent. Accordingly, by appropriate distribution of proton energies, the dose can be uniform across the target and essentially zero deep to the target and the atomic composition of the irradiated material. The dose proximal to the target is lower compared with that in photon techniques, for all except superficial targets This resultant closer approximation of the planning treatment volume (PTV) to the CTV/GTV (grossly evident tumor volume/subclinical tumor extensions) constitutes a clinical gain by definition; i.e. a smaller treatment volume that covers the target three dimensionally for the entirety of each treatment session provides a clinical advantage. Several illustrative clinical dose distributions are presented and the clinical outcome results are reviewed briefly. An important technical advance will be the use of intensity modulated proton radiation therapy, which achieves contouring of the proximal edge of the SOBP (spread out Bragg peak) as well as the distal edge. This technique uses pencil beam scanning. To permit further progressive reductions of the PTV, 4-D treatment planning and delivery is required. The fourth dimension is time, as the position and contours of the tumor and the adjacent critical normal tissues are not constant. A potentially valuable new method for assessing the clinical merits of each of a large number of treatment plans is the evaluation of multidimensional plots of the complication probabilities for each of 'n' critical normal tissues/ structures for a specified tumor control probability. The cost of proton therapy compared with that of very high technology photon therapy is estimated and evaluated. The differential is estimated to be approximately 1.5 provided there were to be no charge for the original facility and that there were sufficient patients for operating on an extended schedule (6-7 days of 14-16 h) with > or = two gantries and one fixed horizontal beam.
Acta Oncologica 01/2003; 42(8):800-8. · 3.33 Impact Factor
