EVALVACIJA INTRAFRAKCIJSKIH PREMIKOV PRI OBSEVANJU KARCINOMA PROSTATE.
Introduction:The evaluation of intrafraction motion of prostate cancer during the radiation therapy process, which includes monitoring of the movement of the patient and of the internal organs, is a common process in clinical practice and has a significant impact on determining the size o f the heal...
| Publicado en: | Bulletin: Newsletter of the Society of Radiographers of Slovenia & the Chamber of Radiographers of Slovenia Vol. 33; pp. 15 - 17 |
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| Autores principales: | , , , , |
| Formato: | abstract research Journal Article |
| Publicado: |
Slovenian Society of Radiographers
2016 Supplement
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| Acceso en línea: | Ver este registro en EBSCOhost |
| Sumario: | Introduction:The evaluation of intrafraction motion of prostate cancer during the radiation therapy process, which includes monitoring of the movement of the patient and of the internal organs, is a common process in clinical practice and has a significant impact on determining the size o f the healthy margins. Purpose:The purpose of the study was to improve the quality of therapy in the radical radiotherapy of prostate cancer by calculating the appropriate size of the healthy margins according to the Van Herk formula. Methods: The study included 9 patients with prostate cancer who received volumetric modulated radiation therapy (VMAT) in the combination with the on-line image guided radiotherapy (IGRT). Three intraprostatic gold fiducial markers were inserted in the prostate by ultrasound before the radiotherapy, in order to allow localisation of the prostate on the electronic portal imaging device (EPID). Systematic population error (I) and random population error (o) of movements were based on daily pre- and post-treatment images. Clinical target volume (CTV) and planning target volume (PTV), the healthy margins were calculated according to Van Herk formula. Results and discussion: The average movements and standard deviations of intrafraction prostate movements were (mean ± SD): -0.11 ± 1.79 mm, -1.07 ± 1.65 m and -0.65 ± 1.56 mm in anterior-posterior (AP), superior-inferior (SI) and medial-lateral (ML) directions, respectively. The average movements and standard deviations of the infraction bone structure movements were (mean ± SD): -0.91 ± 1.33 mm, -0.01 ±1.39 mm and -0.32 ± 1.46 mm in AP, SI and ML directions, respectively. The dominant intrafraction bone structure motions were in the AP and ML directions, while the dominant intrafraction prostate movements were in AP and SI directions. Conclusion: Based on the results we can conclude that a 3 mm extension of CTV-PTV margin, as the lower limit, is enough to ensure that 90% of the patients treated for prostate cancer will receive a minimum cumulative CTV dose higher than or equal to 95% of the prescribed dose, which is good. The reduction of the healthy margin size consequently leads to the potential reduction in the toxic load of the critical organs. Uvod: Vrednotenje intrafrakcijskih prem ikov karcinoma prostate v obsevalnem procesu, ki zajema spremljanje premikanja bolnika in notranjih organov, je običajen proces v klinični praksi, ki pom em bno vpliva na določitev velikosti varnostnih robov. Namen: Namen raziskave je izboljšanje kvalitete obsevanja pri radikalnem obsevanju karcinoma prostate s pom očjo izračuna ustrezne velikosti varnostnega roba po Van Herkovi form uli. Metode dela: V raziskavo je bilo vključenih 9 bolnikov z radikalnim nam enom zdravljenja karcinoma prostate. Vsi bolniki so bili obsevani z volum etrično m odulirano ločno terapijo (VMAT) v kom binaciji z on-line slikovno vodeno radioterapijo (IGRT). Bolniki so imeli pred pričetkom obsevanja s pom očjo ultrazvoka v prostato vstavljena tri zlata zrna, ki om ogočajo lokalizacijo prostate na elektronskem portalnem sistemu (EPID). Izračun populacijske (I) in naključne napake (o) prem ikov je tem eljil na slikanju pred in po končani dnevni obsevalni frakciji. Klinični tarčni volum en-planirani tarčni volum en (CTV-PTV), velikost ustreznih varnostnih robov, je bila izračunana po form uli Van Herka. Rezultati in razprava: Povprečni prem iki in standardni odkloni intrafrakcijskega prem ikanja prostate so: -0,11 ± 1,79 mm, -1,07 ± 1,65 mm, -0,65 ± 1,56 mm v anteriornoposteriorni (AP), superiorno-inferiorni (Sl) in m edio-lateralni (ML) smeri, m edtem ko povprečni prem iki in standardni odkloni intrafrakcijskega prem ikanja kostnih struktur znašajo: -0,91 ± 1.33 mm, -0,01 ± 1,39 m m in -0,32 ± 1,46 mm prav tako v AP, Sl in ML smeri. Intrafrakcijski prem iki kostnih struktur so izrazitejši v AP in ML smeri, m edtem ko so prevladujoči intrafrakcijski prem iki prostate v Sl in ML smereh. Zaključek: Rezultati so pokazali, da 3 m m velik varnostni rob od CTV do PTV zagotavlja, da 90% bolnikov v populaciji prejme 95% ali več predpisane m inim alne kum ulativne doze na CTV področje, kar je dobro. Zmanjšanje velikosti varnostnega roba posledično vodi do potencialnega zmanjšanja toksične obrem enitve kritičnih organov. |
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