Modification of a modulated arc total body irradiation technique: Implementation and first clinical experience for paediatric patients

INTRODUCTION

To implement the modulated arc total body irradiation (MATBI) technique within the existing infrastructure of a radiation oncology department. The technique needed to treat paediatric patients of all ages, some of whom would require general anaesthesia (GA).

METHODS

The MATBI technique required minor modifications to be incorporated within existing departmental infrastructure. Ancillary equipment essential to the technique were identified and in some cases custom designed to meet health and safety criteria. GA equipment was also considered. To evaluate the effectiveness of the implemented technique, an audit of the cases clinically treated was conducted.

RESULTS

A motorised treatment couch was designed to allow the patient to be positioned in stabilisation equipment at a height, then lowered to the floor to accommodate source-to-skin-distances from 180 cm to 198 cm to treat the fixed 40 cm × 40 cm field size. Treatment couch design also facilitated positioning of the bespoke two-part spoiler. While organ at risk dose is limited using a beam weight optimisation technique, the dose is further reduced using compensators placed close to the patient's skin on a 3D printed custom-made support bridge. A digital radiography system is used to verify compensator position. Fifteen patients have been treated to date for various diseases using a variety of dose fractionations ranging from 2 Gy in a single fraction to 12 Gy in 6 fractions. Five patients have required GA due to age or behavioural issues.

CONCLUSION

The modified MATBI technique and the equipment required for treatment delivery has been found to be well tolerated by all patients.

Long-Term Follow-Up of 90Y-Ibritumomab Tiuxetan, Fludarabine, and Total Body Irradiation-Based Nonmyeloablative Allogeneic Transplant Conditioning for Persistent High-Risk B Cell Lymphoma

Nonmyeloablative allogeneic hematopoietic cell transplantation (HCT) can provide prolonged remissions in patients with advanced B cell lymphoma (B-NHL) via the graft-versus-lymphoma effect, although inferior results are seen in patients with chemoresistant, bulky, or aggressive disease. Radioimmunotherapy can safely induce responses in B-NHL with minimal nonhematologic toxicity. Initial results of 90Y-ibritumomab tiuxetan-based allografting demonstrated early safety and disease control in nonremission patients but with short follow-up. Here we report the long-term outcomes of patients treated on this study with specific emphasis on patients achieving early remissions. Eleven of 40 patients were alive at a median follow-up of 9 years (range, 5.3 to 10.2). Fourteen (35%) deaths were due to disease progression and 14 (35%) deaths to complications from HCT. One patient died of a Merkel cell carcinoma. The 5-year overall and progression-free survival for patients with indolent B-NHL was 40% and 27.5%, respectively. None of the patients with diffuse large B cell lymphoma was a long-term disease-free survivor regardless of early remission status. 90Y-ibritumomab tiuxetan-based allografting represents a viable option in patients with indolent histologies. Improved strategies are needed for aggressive B-NHL. The original trial was registered at www.clinicaltrials.gov as NCT00119392.

Optimal conditioning regimen for haplo-identical stem cell transplantation in adult patients with acquired severe aplastic anemia: Prospective de-escalation study of TBI and ATG dose

This prospective study explored an optimal conditioning regimen to ensure engraftment with minimal toxicity in adult patients with severe aplastic anemia (SAA) who received haplo-identical stem cell transplantation from a related mismatched donor (Haplo-SCT). We explored a safe and sufficient dose of rabbit ATG (Thymoglobulin) in combination with 800 cGy total body irradiation (TBI) and fludarabine (Flu, 30 mg/m² /day) for 5 days using step-by-step dose de-escalation. The dose of ATG was de-escalated from 10 mg/kg (group 1), to 7.5 mg/kg (group 2), to 5 mg/kg (group 3), and the TBI dose was reduced to 600 cGy (group 4) beginning in October 2014. If one patient developed transplant-related mortality (TRM) with engraftment in a group, we moved to the next lower dose group. Thirty-four patients were enrolled in groups 1-3 (n = 10) and 4 (n = 24). All patients achieved primary engraftment. The incidence of acute GVHD (grade ≥ 2) and chronic GVHD (≥ moderate) was 29.4% and 14.7%, respectively. With a median follow-up of 56.6 and 21.8 months in groups 1-3 and group 4, respectively, the 2-year probability of overall survival (91.7% in group 4 vs 70% in groups 1-3, P = 0.155) and GVHD-free survival (78.4% in group 4 vs 50% in groups 1-3, P = 0.115) was shown tended to be better in group 4. This study explored an optimal conditioning with step-by-step de-escalation dosage of ATG and TBI to reduce TRM with sustained graft function. TBI-600 cGy/Flu/intermediate-dose ATG resulted in feasible outcomes of Haplo-SCT for adult patients with SAA.

Light and shadows of a new technique: is photon total-skin irradiation using helical IMRT feasible, less complex and as toxic as the electrons one?

BACKGROUND

Radiotherapy is one of the standard treatments for cutaneous lymphoma and Total Skin Electrons Beam Irradiation (TSEBI) is generally used to treat diffuse cutaneous lymphoma and some cases of localized disease. Helical IMRT (HI) allows to treat complex target with optimal dose distribution and organ at risk sparing, so helical tomotherapy has been proposed as alternative technique to TSEBI but only one preliminary report has been published.

METHODS

Three patients treated (from May 2013 to December 2014) with Helical IMRT, with a total dose between 24 and 30 Gy, were retrospectively evaluated. Data about dosimetric features, response and acute toxicity were registered and analyzed. Planned target coverage was compared with daily in vivo measures and dose calculation based on volumetric images used for set up evaluation as well.

RESULTS

The patients had a mean measured surface fraction dose ranging from 1.54 Gy up to 2.0 Gy. A planned target dose ranging from 85 to 120% of prescription doses was obtained. All doses to Organs At Risk were within the required constraints. Particular attention was posed on "whole bone marrow" planned V10Gy, V12Gy and V20Gy values, ranging respectively between 23 and 43%, 20.1 and 38% and 9.8 and 24%. A comparison with the theoretical homologous values obtained with TSEBI has shown much lower values with TSEBI. Even if treatment was given in sequence to the skin of the upper and lower hemi-body, all the patients had anaemia, requiring blood transfusions, leukopenia and thrombocytopenia.

CONCLUSION

Based on our limited results TSEBI should still be considered the standard method to treat total skin because of its pattern of acute and late toxicities and the dose distribution. In this particular case the better target coverage obtained with HI can be paid in terms of worse toxicity. Helical IMRT can instead be considered optimal in treating large, convex, cutaneous areas where it is difficult to use multiple electrons fields in relation with the clinical results and the limited and reversible toxicities.

Total Body Irradiation Is Safe and Similarly Effective as Chemotherapy-Only Conditioning in Autologous Stem Cell Transplantation for Mantle Cell Lymphoma

Autologous stem cell transplant (ASCT) consolidation has become a standard approach for patients with mantle cell lymphoma (MCL), yet there is little consensus on the role of total body irradiation (TBI) as part of high-dose transplantation conditioning. We analyzed 75 consecutive patients with MCL who underwent ASCT at our institution between 2001 and 2011 with either TBI-based (n = 43) or carmustine, etoposide, cytarabine, melphalan (BEAM; n = 32) high-dose conditioning. Most patients (97%) had chemosensitive disease and underwent transplantation in first remission (89%). On univariate analysis, TBI conditioning was associated with a trend toward improved PFS (hazard ratio [HR], .53; 95% confidence interval [CI], .28-1.00; P = .052) and similar OS (HR, .59; 95% CI, .26-1.35; P = .21), with a median follow-up of 6.3 years in the TBI group and 6.6 years in the BEAM group. The 5-year PFS was 66% in the TBI group versus 52% in the BEAM group; OS was 82% versus 68%, respectively. However, on multivariate analysis, TBI-based conditioning was not significantly associated with PFS (HR, .57; 95% CI .24-1.34; P = .20), after controlling for age, disease status at ASCT, and receipt of post-transplantation rituximab maintenance. Likewise, early toxicity, nonrelapse mortality, and secondary malignancies were similar in the 2 groups. Our data suggest that both TBI and BEAM-based conditioning regimens remain viable conditioning options for patients with MCL undergoing ASCT.

Ginger Oleoresin Alleviated γ-Ray Irradiation-Induced Reactive Oxygen Species via the Nrf2 Protective Response in Human Mesenchymal Stem Cells

Unplanned exposure to radiation can cause side effects on high-risk individuals; meanwhile, radiotherapies can also cause injury on normal cells and tissues surrounding the tumor. Besides the direct radiation damage, most of the ionizing radiation- (IR-) induced injuries were caused by generation of reactive oxygen species (ROS). Human mesenchymal stem cells (hMSCs), which possess self-renew and multilineage differentiation capabilities, are a critical population of cells to participate in the regeneration of IR-damaged tissues. Therefore, it is imperative to search effective radioprotectors for hMSCs. This study was to demonstrate whether natural source ginger oleoresin would mitigate IR-induced injuries in human mesenchymal stem cells (hMSCs). We demonstrated that ginger oleoresin could significantly reduce IR-induced cytotoxicity, ROS generation, and DNA strand breaks. In addition, the ROS-scavenging mechanism of ginger oleoresin was also investigated. The results showed that ginger oleoresin could induce the translocation of Nrf2 to cell nucleus and activate the expression of cytoprotective genes encoding for HO-1 and NQO-1. It suggests that ginger oleoresin has a potential role of being an effective antioxidant and radioprotective agent.

Dose Escalation of Total Marrow Irradiation in High-Risk Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Patients with refractory leukemia or minimal residual disease (MRD) at transplantation are at increased risk of relapse. Augmentation of irradiation, especially to sites of disease (ie, bone marrow) is one potential strategy for overcoming this risk. We studied the feasibility of radiation dose escalation in high-risk patients using total marrow irradiation (TMI) in a phase I dose-escalation trial. Four pediatric and 8 adult patients received conditioning with cyclophosphamide and fludarabine in conjunction with image-guided radiation to the bone marrow at 15 Gy and 18 Gy (in 3-Gy fractions), while maintaining the total body irradiation (TBI) dose to the vital organs (lungs, hearts, eyes, liver, and kidneys) at <13.2 Gy. The biologically effective dose of TMI delivered to the bone marrow was increased by 62% at 15 Gy and by 96% at 18 Gy compared with standard TBI. Although excessive dose-limiting toxicity, defined by graft failure or excessive specific organ toxicity, was not encountered, 3 of 6 patients experienced treatment-related mortality at 18 Gy. Thus, we halted enrollment at this dose level and treated an additional 4 patients at 15 Gy. The 1- year overall survival was 42% (95% confidence interval [CI], 15%-67%) and disease-free survival was 22% (95% CI, 4%-49%). The rate of relapse was 36% (95% CI, 10%-62%), and nonrelapse mortality was 42% (95% CI, 14%-70%). This study shows that TMI dose escalation to 15 Gy is feasible with acceptable toxicity in pediatric and adult patients with high-risk leukemia undergoing umbilical cord blood and sibling donor transplantation.

Time- and radiation-dose dependent changes in the plasma proteome after total body irradiation of non-human primates: Implications for biomarker selection

Acute radiation syndrome (ARS) is a complex multi-organ disease resulting from total body exposure to high doses of radiation. Individuals can be exposed to total body irradiation (TBI) in a number of ways, including terrorist radiological weapons or nuclear accidents. In order to determine whether an individual has been exposed to high doses of radiation and needs countermeasure treatment, robust biomarkers are needed to estimate radiation exposure from biospecimens such as blood or urine. In order to identity such candidate biomarkers of radiation exposure, high-resolution proteomics was used to analyze plasma from non-human primates following whole body irradiation (Co-60 at 6.7 Gy and 7.4 Gy) with a twelve day observation period. A total of 663 proteins were evaluated from the plasma proteome analysis. A panel of plasma proteins with characteristic time- and dose-dependent changes was identified. In addition to the plasma proteomics study reported here, we recently identified candidate biomarkers using urine from these same non-human primates. From the proteomic analysis of both plasma and urine, we identified ten overlapping proteins that significantly differentiate both time and dose variables. These shared plasma and urine proteins represent optimal candidate biomarkers of radiation exposure.

Thrombopoietin Receptor Agonist Mitigates Hematopoietic Radiation Syndrome and Improves Survival after Whole-Body Ionizing Irradiation Followed by Wound Trauma

Ionizing radiation combined with trauma tissue injury (combined injury, CI) results in greater mortality and H-ARS than radiation alone (radiation injury, RI), which includes thrombocytopenia. The aim of this study was to determine whether increases in numbers of thrombocytes would improve survival and mitigate H-ARS after CI. We observed in mice that WBC and platelets remained very low in surviving RI animals that were given 9.5 Gy 60Co-γ-photon radiation, whereas only lymphocytes and basophils remained low in surviving CI mice that were irradiated and then given skin wounds. Numbers of RBC and platelets, hemoglobin concentrations, and hematocrit values remained low in surviving RI and CI mice. CI induced 30-day mortality higher than RI. Radiation delayed wound healing by approximately 14 days. Treatment with a thrombopoietin receptor agonist, Alxn4100TPO, after CI improved survival, mitigated body-weight loss, and reduced water consumption. Though this therapy delayed wound-healing rate more than in vehicle groups, it greatly increased numbers of platelets in sham, wounded, RI, and CI mice; it significantly mitigated decreases in WBC, spleen weights, and splenocytes in CI mice and decreases in RBC, hemoglobin, hematocrit values, and splenocytes and splenomegaly in RI mice. The results suggest that Alxn4100TPO is effective in mitigating CI.

DOSE AND GAMMA-RAY SPECTRA FROM NEUTRON-INDUCED RADIOACTIVITY IN MEDICAL LINEAR ACCELERATORS FOLLOWING HIGH-ENERGY TOTAL BODY IRRADIATION

Production of radioisotopes in medical linear accelerators (linacs) is of concern when the beam energy exceeds the threshold for the photonuclear interaction. Staff and patients may receive a radiation dose as a result of the induced radioactivity in the linac. Gamma-ray spectroscopy was used to identify the isotopes produced following the delivery of 18 MV photon beams from a Varian 21EX and an Elekta Synergy. The prominent radioisotopes produced include ¹⁸⁷W, ⁶³Zn, ⁵⁶Mn, ²⁴Na and ²⁸Al in both linac models. The dose rate was measured at the beam exit window (12.6 µSv in the first 10 min) following 18 MV total body irradiation (TBI) beams. For a throughput of 24 TBI patients per year, staff members are estimated to receive an annual dose of up to 750 μSv at the patient location. This can be further reduced to 65 μSv by closing the jaws before re-entering the treatment bunker.

Non-human Primate Total-body Irradiation Model with Limited and Full Medical Supportive Care Including Filgrastim for Biodosimetry and Injury Assessment

An assessment of multiple biomarkers from radiation casualties undergoing limited- or full-supportive care including treatment with filgrastim is critical to develop rapid and effective diagnostic triage strategies. The efficacy of filgrastim with full-supportive care was compared with results with limited-supportive care by analyzing survival, necropsy, histopathology and serial blood samples for hematological, serum chemistry and protein profiles in a non-human primate (Macaca mulatta, male and female) model during 60-d post-monitoring period following sham- and total-body irradiation with 6.5 Gy ⁶⁰Co gamma-rays at 0.6 Gy min^-1 Filgrastim (10 μg kg^-1) was administered beginning on Day 1 post-exposure and continued daily until neutrophil counts were ≥2,000 μL^-1 for two consecutive days. Filgrastim and full-supportive care significantly decreased the pancytopenia duration and resulted in improved animal survival and recovery compared to animals with a limited-supportive care. These findings also identified and validated a multiparametric biomarker panel to support radiation diagnostic device development.

Acute Radiation Syndrome Severity Score System in Mouse Total-Body Irradiation Model

Radiation accidents or terrorist attacks can result in serious consequences for the civilian population and for military personnel responding to such emergencies. The early medical management situation requires quantitative indications for early initiation of cytokine therapy in individuals exposed to life-threatening radiation doses and effective triage tools for first responders in mass-casualty radiological incidents. Previously established animal (Mus musculus, Macaca mulatta) total-body irradiation (γ-exposure) models have evaluated a panel of radiation-responsive proteins that, together with peripheral blood cell counts, create a multiparametic dose-predictive algorithm with a threshold for detection of ~1 Gy from 1 to 7 d after exposure as well as demonstrate the acute radiation syndrome severity score systems created similar to the Medical Treatment Protocols for Radiation Accident Victims developed by Fliedner and colleagues. The authors present a further demonstration of the acute radiation sickness severity score system in a mouse (CD2F1, males) TBI model (1-14 Gy, Co γ-rays at 0.6 Gy min) based on multiple biodosimetric endpoints. This includes the acute radiation sickness severity Observational Grading System, survival rate, weight changes, temperature, peripheral blood cell counts and radiation-responsive protein expression profile: Flt-3 ligand, interleukin 6, granulocyte-colony stimulating factor, thrombopoietin, erythropoietin, and serum amyloid A. Results show that use of the multiple-parameter severity score system facilitates identification of animals requiring enhanced monitoring after irradiation and that proteomics are a complementary approach to conventional biodosimetry for early assessment of radiation exposure, enhancing accuracy and discrimination index for acute radiation sickness response categories and early prediction of outcome.

The Total Body Irradiation Schedule Affects Acute Leukemia Relapse After Matched T Cell-Depleted Hematopoietic Stem Cell Transplantation

PURPOSE

We sought to determine whether the total body irradiation (TBI) schedule affected outcome in patients with acute leukemia in complete remission who received T cell-depleted allogeneic hematopoietic stem cell transplantation from HLA identical siblings.

METHODS AND MATERIALS

The study recruited 55 patients (median age, 48 years; age range, 20-66 years; 30 men and 25 women; 34 with acute myeloid leukemia and 21 with acute lymphoid leukemia). Hyperfractionated TBI (HTBI) (1.2 Gy thrice daily for 4 days [for a total dose of 14.4 Gy] from day -12 to day -9) was administered to 29 patients. Single-dose TBI (STBI) (8 Gy, at a median dose rate of 10.7 cGy/min on day -9) was given to 26 patients.

RESULTS

All patients achieved primary, sustained engraftment with full donor-type chimerism. At 10 years, the overall cumulative incidence of transplant-related mortality was 11% (SE, ±0.1%). It was 7% (SE, ±0.2%) after HTBI and 15% (SE, ±0.5%) after STBI (P=.3). The overall cumulative incidence of relapse was 33% (SE, ±0.5). It was 13% (SE, ±0.5%) after HTBI and 46% (SE, ±1%) after STBI (P=.02). The overall probability of disease-free survival (DFS) was 59% (SE, ±7%). It was 67% (SE, ±0.84%) after HTBI and 37% (SE, ±1.4%) after STBI (P=.01). Multivariate analyses showed the TBI schedule was the only risk factor that significantly affected relapse and DFS (P=.01 and P=.03, respectively).

CONCLUSIONS

In patients with acute leukemia, HTBI is more efficacious than STBI in eradicating minimal residual disease after HLA-matched T cell-depleted hematopoietic stem cell transplantation, thus affecting DFS.

Analysis of gene expression in mouse brain regions after exposure to 1.9 GHz radiofrequency fields

PURPOSE

To assess 1.9 GHz radiofrequency (RF) field exposure on gene expression within a variety of discrete mouse brain regions using whole genome microarray analysis.

MATERIALS AND METHODS

Adult male C57BL/6 mice were exposed to 1.9 GHz pulse-modulated or continuous-wave RF fields for 4 h/day for 5 consecutive days at whole body average (WBA) specific absorption rates of 0 (sham), ∼0.2 W/kg and ∼1.4 W/kg. Total RNA was isolated from the auditory cortex, amygdala, caudate, cerebellum, hippocampus, hypothalamus, and medial prefrontal cortex and differential gene expression was assessed using Illumina MouseWG-6 (v2) BeadChip arrays. Validation of potentially responding genes was conducted by RT-PCR.

RESULTS

When analysis of gene expression was conducted within individual brain regions when controlling the false discovery rate (FDR), no differentially expressed genes were identified relative to the sham control. However, it must be noted that most fold changes among groups were observed to be less than 1.5-fold and this study had limited ability to detect such small changes. While some genes were differentially expressed without correction for multiple-comparisons testing, no consistent pattern of response was observed among different RF-exposure levels or among different RF-modulations.

CONCLUSIONS

The current study provides the most comprehensive analysis of potential gene expression changes in the rodent brain in response to RF field exposure conducted to date. Within the exposure conditions and limitations of this study, no convincing evidence of consistent changes in gene expression was found in response to 1.9 GHz RF field exposure.

Total body irradiation with volumetric modulated arc therapy: Dosimetric data and first clinical experience

BACKGROUND

To implement total body irradiation (TBI) using volumetric modulated arc therapy (VMAT). We applied the Varian RapidArc™ software to calculate and optimize the dose distribution. Emphasis was placed on applying a homogenous dose to the PTV and on reducing the dose to the lungs.

METHODS

From July 2013 to July 2014 seven patients with leukaemia were planned and treated with a VMAT-based TBI-technique with photon energy of 6 MV. The overall planning target volume (PTV), comprising the whole body, had to be split into 8 segments with a subsequent multi-isocentric planning. In a first step a dose optimization of each single segment was performed. In a second step all these elements were calculated in one overall dose-plan, considering particular constraints and weighting factors, to achieve the final total body dose distribution. The quality assurance comprised the verification of the irradiation plans via ArcCheck™ (Sun Nuclear), followed by in vivo dosimetry via dosimeters (MOSFETs) on the patient.

RESULTS

The time requirements for treatment planning were high: contouring took 5-6 h, optimization and dose calculation 25-30 h and quality assurance 6-8 h. The couch-time per fraction was 2 h on day one, decreasing to around 1.5 h for the following fractions, including patient information, time for arc positioning, patient positioning verification, mounting of the MOSFETs and irradiation. The mean lung dose was decreased to at least 80 % of the planned total body dose and in the central parts to 50 %. In two cases we additionally pursued a dose reduction of 30 to 50 % in a pre-irradiated brain and in renal insufficiency. All high dose areas were outside the lungs and other OARs. The planned dose was in line with the measured dose via MOSFETs: in the axilla the mean difference between calculated and measured dose was 3.6 % (range 1.1-6.8 %), and for the wrist/hip-inguinal region it was 4.3 % (range 1.1-8.1 %).

CONCLUSION

TBI with VMAT provides the benefit of satisfactory dose distribution within the PTV, while selectively reducing the dose to the lungs and, if necessary, in other organs. Planning time, however, is extensive.

Mass Spectrometry-Based Metabolomics Identifies Longitudinal Urinary Metabolite Profiles Predictive of Radiation-Induced Cancer

Nonlethal exposure to ionizing radiation (IR) is a public concern due to its known carcinogenic effects. Although latency periods for IR-induced neoplasms are relatively long, the ability to detect cancer as early as possible is highly advantageous for effective therapeutic intervention. Therefore, we hypothesized that metabolites in the urine from mice exposed to total body radiation (TBI) would predict for the presence of cancer before a palpable mass was detected. In this study, we exposed mice to 0 or 5.4 Gy TBI, collected urine samples periodically over 1 year, and assayed urine metabolites by using mass spectrometry. Longitudinal data analysis within the first year post-TBI revealed that cancers, including hematopoietic, solid, and benign neoplasms, could be distinguished by unique urinary signatures as early as 3 months post-TBI. Furthermore, a distinction among different types of malignancies could be clearly delineated as early as 3 months post-TBI for hematopoietic neoplasms, 6 months for solid neoplasms, and by 1 year for benign neoplasms. Moreover, the feature profile for radiation-exposed mice 6 months post-TBI was found to be similar to nonirradiated control mice at 18 months, suggesting that TBI accelerates aging. These results demonstrate that urine feature profiles following TBI can identify cancers in mice prior to macroscopic detection, with important implications for the early diagnosis and treatment.

Low Dose Effects: Benefit or Harm?

This forum article discusses issues related to the effects of low dose radiation, an area that is under intense study but difficult to assess. Experiments with large-scale animal studies are included in this paper; these studies point to the need for international consortia to examine and balance the results of these large-scale studies and databases.

Repetitive exposure to low-dose X-irradiation attenuates testicular apoptosis in type 2 diabetic rats, likely via Akt-mediated Nrf2 activation

To determine whether repetitive exposure to low-dose radiation (LDR) attenuates type 2 diabetes (T2DM)-induced testicular apoptotic cell death in a T2DM rat model, we examined the effects of LDR exposure on diabetic and age-matched control rats. We found that testicular apoptosis and oxidative stress levels were significantly higher in T2DM rats than in control rats. In addition, glucose metabolism-related Akt and GSK-3β function was downregulated and Akt negative regulators PTP1B and TRB3 were upregulated in the T2DM group. Superoxide dismutase (SOD) activity and catalase content were also found to be decreased in T2DM rats. These effects were partially prevented or reversed by repetitive LDR exposure. Nrf2 and its downstream genes NQO1, SOD, and catalase were significantly upregulated by repetitive exposure to LDR, suggesting that the reduction of T2DM-induced testicular apoptosis due to repetitive LDR exposure likely involves enhancement of testicular Akt-mediated glucose metabolism and anti-oxidative defense mechanisms.

Anticancer and Radiosensitization Efficacy of Nanocomposite Withania somnifera Extract in Mice Bearing Tumor Cells

The objective of the present study was to evaluate the anticancer and radio-sensitizing efficacy of a Withania somnifera extract/Gadolinium III oxide nanocomposite (WSGNC) in mice. WSGNC was injected to solid Ehrlich carcinoma-bearing mice via i.p. (227 mg/kg body weight) 3 times/week during 3 weeks. Irradiation was performed by whole body fractionated exposure to 6Gy, applied in 3 doses of 2 Gy/week over 3 weeks. Biochemical analyses as well as DNA fragmentation were performed. Treatment of solid Ehrlich carcinoma bearing mice with WSGNC combined with γ-radiation led to a significant decrease in the tumor size and weight associated with a significant decrease in mitochondrial enzyme activities, GSH content and SOD activity as well as a significant increase in caspase-3 activity, MDA concentration and DNA fragmentation in cancer tissues. Combined treatment of WSGNC and low dose of γ-radiation showed great amelioration in lipid peroxidation and antioxidant status (GSH content and SOD activity) in liver tissues in animals bearing tumors. It is concluded that WSGNC can be considered as a radio-sensitizer and anticancer modulator, suggesting a possible role in reducing the radiation exposure dose during radiotherapy.

Treatment of childhood leukemia with haploidentical hematopoietic stem cell transplantation using parent as donor: a single-center study of 111 case

OBJECTIVE

In the present study, the outcomes of childhood leukemia treated with haplo-HSCT using parent as donor were evaluated and the risk factors for survival were identified.

PATIENTS AND METHODS

111 consecutive cases from March 2002 to March 2012 in our center were analyzed. The median age of patients was 10 (3-14) years old. All patients received unmanipulated combined marrow and peripheral blood stem cells for transplant after conditioning with busulfan and cyclophosphamide (Cy)/Cy and total body irradiation (TBI) plus antithymocyte globulin (ATG).

RESULTS

Durable hematopoietic reconstitution was seen in 98% of recipients. Engraftment failure occurred in 3 cases including 2 cases of father to daughter transplants. One-hundred-day transplant-related mortality (TRM) was only 4.5%. The cumulative incidences of grade II to IV acute graft-versus-host disease (aGvHD) and chronic GvHD (cGvHD) were 47.6% and 28.3%, respectively. With the median follow-up of 32 (12-134) months, 2-year and 5-year overall survival (OS) rates for all patients were 82.1% and 79.2%, respectively. Five-year OS rates for patients in early, intermediate and advanced disease were 84.0%, 81.0%, and 57.1%, respectively (p = 0.08). Five-year OS of transplants in father to son, father to daughter, mother to son, and mother to daughter were was 88.1%, 57.1%, 70.6%, and 82.6%, respectively (p = 0.08).

CONCLUSIONS

Under current protocol, children with leukemia tolerate haplo-HSCT from their parent very well with lower TRM, less cGvHD, and better OS compared with our published data. Pre-transplant disease status and donor- recipient relationship and the recipient age have significant impact on survival.

Delayed Effects of Acute Radiation Exposure in a Murine Model of the H-ARS: Multiple-Organ Injury Consequent to <10 Gy Total Body Irradiation

The threat of radiation exposure from warfare or radiation accidents raises the need for appropriate animal models to study the acute and chronic effects of high dose rate radiation exposure. The goal of this study was to assess the late development of fibrosis in multiple organs (kidney, heart, and lung) in survivors of the C57BL/6 mouse model of the hematopoietic-acute radiation syndrome (H-ARS). Separate groups of mice for histological and functional studies were exposed to a single uniform total body dose between 8.53 and 8.72 Gy of gamma radiation from a Cs radiation source and studied 1-21 mo later. Blood urea nitrogen levels were elevated significantly in the irradiated mice at 9 and 21 mo (from ∼22 to 34 ± 3.8 and 69 ± 6.0 mg dL, p < 0.01 vs. non-irradiated controls) and correlated with glomerosclerosis (29 ± 1.8% vs. 64 ± 9.7% of total glomeruli, p < 0.01 vs. non-irradiated controls). Glomerular tubularization and hypertrophy and tubular atrophy were also observed at 21 mo post-total body irradiation (TBI). An increase in interstitial, perivascular, pericardial and peribronchial fibrosis/collagen deposition was observed from ∼9-21 mo post-TBI in kidney, heart, and lung of irradiated mice relative to age-matched controls. Echocardiography suggested decreased ventricular volumes with a compensatory increase in the left ventricular ejection fraction. The results indicate that significant delayed effects of acute radiation exposure occur in kidney, heart, and lung in survivors of the murine H-ARS TBI model, which mirrors pathology detected in larger species and humans at higher radiation doses focused on specific organs.

Accelerating total body irradiation with large field modulated arc therapy in standard treatment rooms without additional equipment

PURPOSE

The aim of this study was to develop a generic and ultra-efficient modulated arc technique for treatment with total body irradiation (TBI) without additional equipment in standard treatment rooms.

METHODS

A continuous gantry arc between 300° and 70° composed of 26 subarcs (5° per subarc) using a field size of 40 × 40 cm(2) was used to perform the initial beam data measurements. The profile was measured parallel to the direction of gantry rotation at a constant depth of 9 cm (phantom thickness 18 cm). Beam data were measured for single 5° subarcs, dissecting the individual contribution of each subarc to a certain measurement point. The phantom was moved to 20 measurement positions along the profile. Then profile optimization was performed manually by varying the weighting factors of all segments until calculated doses at all points were within ± 1 %. Finally, the dose distribution of the modulated arc was verified in phantom thicknesses of 18 and 28 cm.

RESULTS

The measured profile showed a relative mean dose of 99.7 % [standard deviation (SD) 0.7 %)] over the length of 200 cm at a depth of 9 cm. The measured mean effective surface dose (at a depth of 2 cm) was 102.7 % (SD 2.1 %). The measurements in the 28 cm slab phantom revealed a mean dose of 95.9 % (SD 2.9 %) at a depth of 14 cm. The mean dose at a depth of 2 cm was 111.9 % (SD 4.1 %). Net beam-on-time for a 2 Gy fraction is approximately 8 min.

CONCLUSION

This highly efficient modulated arc technique for TBI can replace conventional treatment techniques, providing a homogeneous dose distribution, dosimetric robustness, extremely fast delivery, and applicability in small treatment rooms, with no need for additional equipment.

Radiation Therapy for Cutaneous T-Cell Lymphomas

Radiation therapy is an extraordinarily effective skin-directed therapy for cutaneous T-cell lymphomas. Lymphocytes are extremely sensitive to radiation and a complete response is generally achieved even with low doses. Radiation therapy has several important roles in the management of mycosis fungoides. For the rare patient with unilesional disease, radiation therapy alone is potentially curative. For patients with more advanced cutaneous disease, radiation therapy to local lesions or to the entire skin can effectively palliate symptomatic disease and provide local disease control. Compared with other skin-directed therapies, radiation therapy is particularly advantageous because it can effectively penetrate and treat thicker plaques and tumors.

CD34+ selection and the severity of oropharyngeal mucositis in total body irradiation-based allogeneic stem cell transplantation

OBJECTIVE

The purpose of the present study was to evaluate the impact of ex vivo T cell depleted (TCD) by CD34+ selection on the incidence and severity of oropharyngeal mucositis (OM) after myeloablative allogeneic stem cell transplant (allo-SCT) with total body irradiation (TBI) conditioning. This approach has the advantage of avoiding methotrexate for graft versus host disease (GVHD) prophylaxis.

PATIENTS AND METHODS

We analyzed the incidence and severity of OM in a cohort of 105 consecutive patients who underwent CD34+ selected (peripheral blood stem cells (PBSCs) from human leukocyte antigen (HLA)-identical siblings) allo-SCT with total body irradiation (TBI) conditioning. OM was graded by the World Health organization (WHO) and the Bearman regimen-related toxicity (RRT) scales.

RESULTS

The incidence of WHO grade 3-4 OM was 34.3 %. There were no cases of grade 3-4 OM by the RRT scale. Significant correlation was found between the severity of OM and the use of intravenous (IV) narcotic medications (r (2) = 0.15, p = 0.004), total parenteral nutrition (TPN; r (2) = 0.68, p < 0.001), and hospital length of stay (LOS) (r (2) = 0.12, p = 0.01).

DISCUSSION

TBI-induced OM can inflict significant morbidity in the early transplant period, and the incidence of WHO grade 3-4 OM can exceed 50 % when methotrexate is used for GVHD prophylaxis. In the CD34+ selected setting, methotrexate is avoided and the incidence of WHO grade 3-4 OM, use of TPN, and need for narcotic analgesia appear to be lower than historic evidence from standard T-replete allogeneic transplantation.

CONCLUSION

We conclude that toxicity from OM is tolerable in CD34+ selected allo-SCT and should be prospectively measured in randomized trials comparing CD34+ selection versus T-replete transplantation.

Resident microglia, and not peripheral macrophages, are the main source of brain tumor mononuclear cells

Gliomas consist of multiple cell types, including an abundant number of microglia and macrophages, whereby their impact on tumor progression is controversially discussed. To understand their unique functions and consequently manipulate either microglia or macrophages in therapeutic approaches, it is essential to discriminate between both cell populations. Because of the lack of specific markers, generally total body irradiated chimeras with labeled bone marrow cells were used to identify infiltrated cells within the brain. However, total body irradiation (TBI) affects the blood-brain barrier integrity, which in turn potentially facilitates immune cell infiltration. In this study, changes on the blood-brain barrier were avoided using head-protected irradiation (HPI). Head protection and total body irradiated chimeras exhibited similar reconstitution levels of the myeloid cell lineage in the blood, enabling the comparable analyses of brain infiltrates. We demonstrate that the HPI model impeded a massive unspecific influx of donor-derived myeloid cells into naive as well as tumor-bearing brains. Moreover, experimental artifacts such as an enlarged distribution of infiltrated cells and fourfold increased tumor volumes are prevented in head-protected chimeras. In addition, our data evidenced for the first time that microglia are able to up-regulate CD45 and represent an inherent part of the CD45(high) population in the tumor context. All in all, HPI allowed for the unequivocal distinction between microglia and macrophages without alterations of tumor biology and consequently permits a detailed and realistic description of the myeloid cell composition in gliomas.