Avtor/Urednik		Erkal, Haldun Suekrue; Serin, Meltem
Naslov		Correlation of clinical target volume and the margins to define planning target volume with beam arrangements for three-dimensional conformal radiation therapy delivery for prostate cancer
Prevedeni naslov		Primerjava med kliničnim tarčnim volumnom in varnostnim robom, ki določata planirni tarčni volumen ter obliko polj pri tridimenzionalni konformni radioterapiji raka prostate
Tip		članek
Vir		Radiol Oncol
Vol. in št.		Letnik 39, št. 4
Leto izdaje		2005
Obseg		str. 273-8
Jezik		eng
Abstrakt		Background. A conceptual study was undertaken to correlate the clinical target volume and the margins to define the planning target volume with the beam arrangements for a three-dimensional conformal radiation therapy delivery on two patients with prostate cancer having considerably different prostate shapes and volumes. Material and methods. The clinical target volume was defined as prostate and seminal vesicles. Uniform margins of 0.4, 0.8 and 1.2 cm were added around the clinical target volume to define three planning target volumes. Three well-established coplanar beam arrangements were simulated for all planning target volumes. Dose-volume histograms were calculated and quantitatively compared. Results. The mean dose (Dm) for PTVs ranged from 98.7 to 99.9%, with standard deviations ranging from 1.5 to 1.7%. Plan I appeared to be the best considering the Dm for the rectum, whereas Plan II appeared to be the best considering V95 (fraction of volume receiving a dose higher than 95% of the isocenter dose for the rectum). Plan III appeared to be the best considering the Dm and V95 for the bladder and also considering the Dm and V50 for the femur. Conclusions. This conceptual study suggested that the differences in shapes and volumes of planning target volume might be taken into consideration in an attempt to individually establish the optimum beam arrangements for three-dimensional conformal radiation therapy delivery in prostate cancer.
Izvleček		Izhodišča. Primerjalna študija je bila opravljena na dveh bolnikih z rakom prostate različnih oblik in volumnov. Želeli smo ugotoviti razmerje med kliničnim tarčnim volumnom in varnostnim robom, ki določata planirni tarčni volumen (PTV) ter obliko polj pri tridimenzionalni konformni radioterapiji. Material in metode. Klinični tarčni volumen je vključeval prostato in seminalne vezikule. Varnostne robove dolžin 0,4 cm, 0,8 cm in 1,2 cm smo enakomerno dodali na klinični tarčni volumen in tako določili tri PTV. Pri vseh PTV smo simulirali tri dobro osnovana istoravninska (koplanarna) polja. Naredili smo histograme, ki so kazali razmerje med dozo in volumnom ter jih med seboj kvantitativno primerjali. Rezultati. Povprečna doza za PTV je bila v razponu od 98,7 do 99,9%, s standardno deviacijo med 1,5 in 1,7%. Plan I je bil najboljši glede na povprečno dozo sevanja, ki ga je prejel rektum, medtem ko je bil Plan II najboljši glede na V95 za rektum (delež volumna, ki prejme dozo višjo od 95% doze določene v izocentru). Plan III je bil najboljši tako glede na povprečno dozo sevanja in V95 za mehur kot tudi glede na povprečno dozo sevanja in V50 za glavice kolkov. Zaključki. Primerjalna študija kaže, da moramo upoštevati razlike v oblikah in volumnih planirnih tarčnih volumnov. Takšen pristop nam omogoča individualno določevanje optimalnih polj potrebnih za tridimenzionalno konformno radioterapijo v primeru raka prostate.
Deskriptorji		PROSTATIC NEOPLASMS RADIOTHERAPY DOSAGE