Acute side effects of pelvic and abdominal irradiation

Obsevanje v področju trebuha in medenice je povezano s pojavom akutnih stranskih učinkov organov, ki se nahajajo v bližini obsevalnega tarčnega volumna. Prizadeto je predvsem tkivo z visoko proliferativno aktivnostjo celic - sluznice sečnega mehurja in gastrointestinalnega trakta, kostni mozeg in koža. Osnovni mehanizem nastanka je poškodba zarodnih celic, ki poruši ravnotežje med odmiranjem zrelih celic in nastajanjem novih. Temu se pridruži še vnetni odziv. Simptomi se običajno pojavijo 2 do 3 tedne po začetku obsevanja in trajajo še nekaj tednov po zaključku zdravljenja. Izrednega pomena je spodbujanje bolnikov k ustreznim preventivnim ukrepom. Zdravljenje je konzervativno in odvisno od stopnje izraženosti težav.Irradiation of the abdominal and pelvic cavities can result in acute side effects that are seen in the organs situated near the radiation target volume. The effect of radiotherapy is most potent against tissues with a high cell turnover – mucosa of the bladder and gastrointestinal tract, bone marrow, and skin. The acute symptoms are based on the radiation-induced damage to stem cells, resulting in an imbalance between ongoing cell loss and new cell production. This process is accompanied by inflammatory changes. Acute side effects usually present within 2-3 weeks after the onset of radiation and resolve in a couple of weeks after the completion of treatment. Encouraging patients to take appropriate preventive measures is of utmost importance. Treatment is conservative and depends on the severity of side effects

Akutni stranski učinki obsevanja trebuha in medenice

Irradiation of the abdominal and pelvic cavities can result in acute side effects that are seen in the organs situated near the radiation target volume. The effect of radiotherapy is most potent against tissues with a high cell turnover – mucosa of the bladder and gastrointestinal tract, bone marrow, and skin. The acute symptoms are based on the radiation-induced damage to stem cells, resulting in an imbalance between ongoing cell loss and new cell production. This process is accompanied by inflammatory changes. Acute side effects usually present within 2-3 weeks after the onset of radiation and resolve in a couple of weeks after the completion of treatment. Encouraging patients to take appropriate preventive measures is of utmost importance. Treatment is conservative and depends on the severity of side effects.Obsevanje v področju trebuha in medenice je povezano s pojavom akutnih stranskih učinkov organov, ki se nahajajo v bližini obsevalnega tarčnega volumna. Prizadeto je predvsem tkivo z visoko proliferativno aktivnostjo celic - sluznice sečnega mehurja in gastrointestinalnega trakta, kostni mozeg in koža. Osnovni mehanizem nastanka je poškodba zarodnih celic, ki poruši ravnotežje med odmiranjem zrelih celic in nastajanjem novih. Temu se pridruži še vnetni odziv. Simptomi se običajno pojavijo 2 do 3 tedne po začetku obsevanja in trajajo še nekaj tednov po zaključku zdravljenja. Izrednega pomena je spodbujanje bolnikov k ustreznim preventivnim ukrepom. Zdravljenje je konzervativno in odvisno od stopnje izraženosti težav

Preoperative radiochemotherapy for patients with unresectable stomach carcinoma

Osnovno zdravljenje karcinoma želodca je radikalna resekcija. Ob postavitvi diagnoze je bolezen neresktabilna pri približno 50 % bolnikov. Znano je, da predoperativna radiokemoterapija lahko zmanjša tumor, kar povečuje možnost radikalne resekcije in podaljša preživetje teh bolnikov. V Sloveniji smo pri bolnikih z neresektabilnim nemetastatskim karcinomom želodca predoperativno radiokemoterapijo uvedli leta 2006. Uporabljamo 3-dimenzionalno konformalno načrtovanje obsevanja z računalniško tomografijo ter sočasno kemoterapijo s 5-FU in cisplatinom. Do sedaj je omenjeno zdravljenje prejelo 36 bolnikov. 19 bolnikov je bilo operiranih. Pri 12 (63 %) je bila bolezen odstranjena v celoti, pri 3 (16 %) je bil prisoten mikroskopski ostanek (R1 resekcija), pri 4 (21 %) pa je bil opravljen le paliativni poseg. Podrobnejša analiza bo opravljena po zdravljenju večjega števila bolnikov.Radical resection is the basic treatment for stomach carcinoma. At the time of diagnosis, the disease is unresectable in nearly 50% of patients. It is known that preoperative radiochemotherapy can downstage the tumor and thereby allowing higher probability of radical resection and improving survival of patients. In 2006 preoperative radiochemotherapy was started in Slovenia for patients with non-metastatic unresectable stomach tumors. Three-dimensional conformal treatment planning with computer tomography and concomitant chemotherapy with 5-FU and cisplatin were used. So far, 36 patients received the above-mentioned treatment. In nineteen patients who were operated on so far, radical resection was performed in 12 (63%). In 3 (16%) patients microscopic residual disease (R1 resection) was found, and in 4 (21%) patients, only paliative surgery was performed. A detailed analysis of treatment success will be performed after obtaining the treatment results of greater number of treated patients

Influence of the laser-beam intensity distribution on the performance of directed energy deposition of an axially fed metal powder

This paper investigates the influence of laser-beam intensity distribution (LBID) on the performance of the annular laser-beam directed energy deposition (DED) process with axial powder delivery. Three different LBIDs: Gaussian-like (G-LBID), top-hat-like (TH-LBID) and ring (R-LBID) at two LBID diameters were used. The process performance was characterised qualitatively in terms of the melt-pool shape and the process stability and quantitatively by powder-catchment efficiency, selected geometrical and metallurgical properties of the clad. The observed influence of LBID on process performance, as determined by the relationship between LBID and powder stream density distribution (PSDD), decreased with increasing mean surface-energy density and was more significant at larger LBID diameter. The highest powder-catchment efficiencies (90% and 87%) were achieved with the G-LBID and TH-LBID, whose high-intensity centre is aligned with the peak of the Gaussian-like PSDD. A lower powder-catchment efficiency of 77% was achieved with the R-LBID, whose high-intensity region is located at the edge of the melt pool with minimum powder density. However, this also results in the highest and most uniform dilution, the highest metallurgical bond ratio and the lowest lack of fusion porosity at the clad-substrate interface. In addition, the process was stable at the lower values of mean surface-energy density with R-LBID, while balling instability was observed with G-LBID and TH-LBID. It can be concluded that the use of R-LBID at lower values of mean surface-energy density improves the performance of the DED process with axial powder feed in terms of process stability and metallurgical properties of the clad