The IAEA remote audit of small field dosimetry for testing the implementation of the TRS-483 code of practice.

BACKGROUND: The TRS­483, an IAEA/AAPM International Code of Practice on dosimetry of small static photon fields, underwent testing via an IAEA coordinated research project (CRP). Alongside small field output factors (OFs) measurements using active dosimeters by CRP participants, the IAEA Dosimetry Laboratory received a mandate to formulate a remote small field dosimetry audit method using its passive dosimetry systems. PURPOSE: This work aimed to develop a small field dosimetry audit methodology employing radiophotoluminescent dosimeters (RPLDs) and radiochromic films. The methodology was subsequently evaluated through a multicenter pilot study with CRP participants. METHODS: The developments included designing and manufacturing a dosimeter holder set and the characterization of an RPLD system for measurements in small photon fields using the new holder. The audit included verification of small field OFs and lateral beam profiles for small fields. At first, treatment planning system (TPS) calculated OFs were checked against a reference data set that was available for conventional linacs. Second, calculated OFs were verified through the RPLD measurement of point doses in a machine-specific reference field, 4 cm × 4 cm, 2 cm × 2 cm, and 1 cm × 1 cm, corresponding size circular fields or nearest achievable field sizes. Lastly, profile checks in in-plane and cross-plane directions were done for the two smallest fields by comparing film measurements with TPS calculations at 20%, 50%, and 80% isodose levels. RESULTS: RPLD correction factors for small field measurements were approximately unity. However, they influenced the dose determination's overall uncertainty in small fields, estimated at 2.30% (k = 1 level). Considering the previous experience in auditing reference beam output following the TRS-398 Code of Practice, the acceptance limit of 5% for the ratio of the dose determined by RPLD to the dose calculated by TPS, DRPLD/DTPS, was considered adequate. The multicenter pilot study included 15 participants from 14 countries (39 beams). Consistent with the previous findings, the results of the OF check against the reference data confirmed that TPSs tend to overestimate OFs for the smallest fields included in this exercise. All except three RPLD measurement results were within the acceptance limit, and the spread of results increased for smaller field sizes. The differences between the film measured and TPS calculated dose profiles were within 3 mm for most of the beams checked; deviated results revealed problems with TPS commissioning and calibration of the treatment unit collimation systems. CONCLUSION: The newly developed small field dosimetry audit methodology proved effective and successfully complemented the CRP OF measurements by participants with RPLD audit results.

Use of alternative methods in the treatment of anemia in pregnant women - prospective observational study.

O BJECTIVES: Anemia in pregnant women is a common condition, diagnosed when the concentration of hemoglobin falls below 11 g/dL. Taking into consideration the accounts of nephrologists about good results of treatment of secondary anemia using erythropoietin in patients with renal failure, we tried to use EPO to cure anemia in pregnant women. The aim of the study was to evaluate the results of EPO treatment on pregnant women diagnosed with iron deficiency anemia, as well as possible side effects. MATERIAL AND METHODS: The study consisted of 25 patients: Group I - treated with iron supplement administered parenterally - Ferrum Lek every two days intramuscularly. Group II - treated with recombinant human erythropoietin - 1000 j intravenously every three days, with oral iron sup- plements. RESULTS: After a week of treatment the positive response was higher in the second group (92.3% in II, vs 33.3% in I, p < 0.005). The average increase of hemoglobin and RBC was significantly higher in II group. An increase in hemoglobin did not correlate with the age of women (r = 0.07) or with the duration of pregnancy (r = 0.08). However, a negative correlation was found between basic hemoglobin level and its increase after treatment (r = 0.602). CONCLUSIONS: EPO administered with the oral dose of iron in pregnant women with anemia caused by iron deficiency shows higher effectiveness than the use of iron preparations parenterally. The usage of EPO during pregnancy is not related to any dangerous side effects for the mother or fetus.