IMRT using simultaneous integrated boost (66 Gy in 6 weeks) with and without concurrent chemotherapy in head and neck cancer – toxicity evaluation

AimTo evaluate the toxicity of intensity-modulated radiotherapy with simultaneous integrated boost (SIB-IMRT) in head and neck cancer patients treated using a protocol comprising 66 Gy to the PTV1 (planning target volume; region of macroscopic tumour) and 60 Gy and 54 Gy to the regions with high risk (PTV2) and low risk (PTV3) of subclinical disease in 30 fractions in six weeks.Material and MethodsBetween December 2003 and February 2006, 48 patients (median age 55; range 25–83, performance status 0–1) with evaluable non-metastatic head and neck cancer of various localizations and stages (stages: I–1; II–8; III–12; IV–27 patients, resp.) were irradiated according to the protocol and followed (median follow-up 20 months; range 4–42). Ten patients underwent concurrent chemotherapy (CT) and in 15 patients the regimen was indicated postoperatively because of close or positive margins. In all cases the regimen was used as an alternative to conventional radiotherapy (70 Gy in 7 weeks). The acute and late toxicities were evaluated according to RTOG and RTOG/EORTC toxicity scales, respectively.ResultsAll patients finished the treatment without the need for interruption due to acute toxicity. No patient experienced grade 4 toxicity. More severe acute toxicity was observed in patients with CT, but the most severe toxicity was grade 3. Grade 3 toxicity was observed in the skin, mucous membrane, salivary glands, pharynx/oesophagus and larynx in 8.4%, 35.4%, 39.6% and 2.1%, in the CT subgroup in 10%, 100%, 90%, 10%, respectively. The trend of impairment of acute toxicity by concurrent chemotherapy was statistically confirmed by Fisher's exact test (for mucous membranes p=0.000002 and pharyngeal/oesophageal toxicity p=0.0004). The most severe late toxicity was grade 2 subcutaneous tissue (34.2%), mucous membrane (36.8%) and larynx (11.1%), grade 3 in salivary gland (2.6%) and grade 1 in skin (84.2%) and spinal cord (5.4%). The late toxicity was not increased by chemotherapy.ConclusionIn light of the toxicity profile we consider the presented regimen to be an alternative to conventional radiotherapy 70 Gy in 7 weeks. The addition of CT requires more intensive supportive care

Analysis of Ballistic Impact of 7.62 mm FMJ M80 Rifle Projectile into Twaron/UHMWPE Composite Armor

This article deals with the ballistic impact of the 7.62 mm FMJ M80 rifle projectile into the laminated Twaron/UHMWPE composite armor. The armor composition consisted of composite panels made from Twaron CT 747 para-aramid fabric and ultra-high-molecular-weight Endumax Shield XF33 polyethylene. To analyze the ballistic impact and to verify the resistance of the designed armor according to the NATO AEP 4569 STANAG standard, protection level 1, 7.62 × 51 mm FMJ NATO M80 rifle cartridges with lead projectiles were used in the ballistic experiment. After the projectile impact, the damage failure mechanisms of the composite panels were documented. As part of the evaluation of the experiments, the initial microstructure of the composite panels was documented, and subsequently, the damaged areas of the composite armor after the ballistic experiment were also documented. Optical and scanning electron microscopy were used to document the structures. The important parameter of composite armor is its mechanical properties. The surface hardness of the composite panels was measured by the Shore D method using the hardness tester DIGI-Test II. The results obtained from the ballistic experiment demonstrate that the designed Twaron/Endumax armor was not penetrated. This armor has sustained multiple impacts for all three 7.62 mm FMJ M80 projectiles and is suitable for the construction of armor protection

Analysis of Ballistic Impact of 7.62 mm FMJ M80 Rifle Projectile into Twaron/UHMWPE Composite Armor

This article deals with the ballistic impact of the 7.62 mm FMJ M80 rifle projectile into the laminated Twaron/UHMWPE composite armor. The armor composition consisted of composite panels made from Twaron CT 747 para-aramid fabric and ultra-high-molecular-weight Endumax Shield XF33 polyethylene. To analyze the ballistic impact and to verify the resistance of the designed armor according to the NATO AEP 4569 STANAG standard, protection level 1, 7.62 x 51 mm FMJ NATO M80 rifle cartridges with lead projectiles were used in the ballistic experiment. After the projectile impact, the damage failure mechanisms of the composite panels were documented. As part of the evaluation of the experiments, the initial microstructure of the composite panels was documented, and subsequently, the damaged areas of the composite armor after the ballistic experiment were also documented. Optical and scanning electron microscopy were used to document the structures. The important parameter of composite armor is its mechanical properties. The surface hardness of the composite panels was measured by the Shore D method using the hardness tester DIGI-Test II. The results obtained from the ballistic experiment demonstrate that the designed Twaron/Endumax armor was not penetrated. This armor has sustained multiple impacts for all three 7.62 mm FMJ M80 projectiles and is suitable for the construction of armor protection

Utilization of cone-beam CT for offline evaluation of target volume coverage during prostate image-guided radiotherapy based on bony anatomy alignment

AimTo assess target volume coverage during prostate image-guided radiotherapy based on bony anatomy alignment and to assess possibility of safety margin reduction.BackgroundImplementation of IGRT should influence safety margins. Utilization of cone-beam CT provides current 3D anatomic information directly in irradiation position. Such information enables reconstruction of the actual dose distribution.Materials and methodsSeventeen prostate patients were treated with daily bony anatomy image-guidance. Cone-beam CT (CBCT) scans were acquired once a week immediately after bony anatomy alignment. After the prostate, seminal vesicles, rectum and bladder were contoured, the delivered dose distribution was reconstructed. Target dose coverage was evaluated by the proportion of the CTV encompassed by the 95% isodose. Original plans employed a 1[[ce:hsp sp="0.25"/]]cm safety margin. Alternative plans assuming a smaller 7[[ce:hsp sp="0.25"/]]mm margin between CTV and PTV were evaluated in the same way. Rectal and bladder volumes were compared with the initial ones. Rectal and bladder volumes irradiated with doses higher than 75[[ce:hsp sp="0.25"/]]Gy, 70[[ce:hsp sp="0.25"/]]Gy, 60[[ce:hsp sp="0.25"/]]Gy, 50[[ce:hsp sp="0.25"/]]Gy and 40[[ce:hsp sp="0.25"/]]Gy were analyzed.ResultsIn 12% of reconstructed plans the prostate coverage was not sufficient. The prostate underdosage was observed in 5 patients. Coverage of seminal vesicles was not satisfactory in 3% of plans. Most of the target underdosage corresponded to excessive rectal or bladder filling. Evaluation of alternative plans assuming a smaller 7[[ce:hsp sp="0.25"/]]mm margin revealed 22% and 11% of plans where prostate and seminal vesicles coverage, respectively, was compromised. These were distributed over 8 and 7 patients, respectively.ConclusionSufficient dose coverage of target volumes was not achieved for all patients. Reducing of safety margin is not acceptable. Initial rectal and bladder volumes cannot be considered representative for subsequent treatment

IMRT with the Use of Simultaneous Integrated Boost in Treatment of Head and Neck Cancer: Acute Toxicity Evaluation

Acute toxicity has been evaluated in head and neck cancer patients treated with intensity-modulated radiotherapy using simultaneous integrated boost (SIB-IMRT). The basis of the treatment protocol is an irradiation in 30 fractions with a total dose: 66 Gy to the region of macroscopic tumor, 60 Gy to the region of high-risk subclinical disease and 54 Gy to the region of low-risk subclinical disease. Between December 2003 and September 2005, 38 patients with carcinoma of different locations in the head and neck region were irradiated. Five patients underwent concurrent chemotherapy (weekly cisplatin). Acute toxicity was evaluated according to Radiation Therapy Oncology Group toxicity scale for skin, mucous membrane, salivary glands, pharynx and esophagus and larynx. All 38 patients completed the therapy without urgency of interruption due to acute toxicity of radiotherapy. No patient experienced grade 4 toxicity. More severe toxicity was observed in patients with concurrent chemotherapy. The results confirm that the irradiation according to our SIB-IMRT protocol is a therapy with acceptable toxicity and there is a space for radiobiological enhancement of this regimen by concurrent chemotherapy, e.g. weekly cisplatin