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Biomedical subjects

M Zouhar

Publications and source records attributed to M Zouhar.

6 recordsLinked to original sources
PubMed2005

Clinical results of intensity-modulated radiation therapy (IMRT) for tumors of the head and neck region.

Intensity-modulated radiation therapy (IMRT) is an advanced form of the three-dimensional conformal radiation therapy (3D-CRT). Highly conformal dose distribution is the basic feature of IMRT. The head and neck region is suitable for this new technology since the primary tumor is often surrounded by several critical structures. IMRT offers the ability of dose escalation due to steep dose gradient towards healthy tissues. In this review, clinical results of IMRT in several head and neck sites are presented, including intracranial tumors. Parotid-sparing strategies and patterns of local-regional failures are analyzed. The possibilities of irradiation of recurrent malignancies are mentioned. In perspective, the potential of IMRT should be explored in conjunction with altered fractionation regimens, including simultaneous integrated boost (SIB). Particularly, studies with dose escalation are desirable.

Brain Neoplasms↗
PubMed2001

Conformal radiotherapy for prostate cancer--longer duration of acute genitourinary toxicity in patients with prior history of invasive urological procedure.

The incidence and predictors of acute toxicity were evaluated in patients treated with three-dimensional conformal radiotherapy (3D-CRT) for localized prostate cancer. Between December 1997 and November 1999, 116 patients with T1-T3 prostatic carcinoma were enrolled in the study. Ninety patients were treated with 70 Gy and 26 patients with T3 tumors received 74 Gy. Of the 116 patients 42 (36.2%) had a prior history of invasive urological procedure (IUP) (transurethral resection of the prostate or transvesical prostatectomy for benign prostatic hyperplasia). Acute gastrointestinal (GI) and genitourinary (GU) symptoms were graded according to the EORTC/RTOG scoring system. Toxicity duration after the completion of 3D-CRT was recorded. The majority of patients experienced only mild or no (Grade 1) acute toxicities. Medications for GI and GU symptoms (Grade 2) were required by 28.4% and 12.9% of patients, respectively. Only one case of Grade 3 GI toxicity (0.9%) was observed. Seven patients (6.1%) experienced severe GU toxicity (Grade 3 or 4). No correlation was found between acute toxicity and age, stage, dose (70 Gy vs. 74 Gy), IUP and pelvic lymphadenectomy. A significant relationship was observed between the duration of acute GU toxicity and prior IUP. Symptoms persisted for more than 4 weeks in 51.9% and 26.0% of patients with and without a prior history of IUP, respectively (p = 0.02). The incidence of acute complications, associated with 3D-CRT for prostate cancer, was acceptable in our cohort of patients. A prior history of IUP resulted in a significantly longer duration of acute GU toxicity.

Age Factors↗
PubMed1983

[Chronic progressive radiation myelopathy].

Radiation dose absorbed by spinal tissue in 4 cases of chronic progressive myelopathy was analysed so that the criteria could be established for choosing cases in which myelopathy was to be presumed. Nevertheless, neither regressive nor vascular lesion was found in 10 autopsies fitting the criteria. The fact was explained by individual variability or other unknown factors.

Adolescent↗