The effects of gradual dynamization on fracture healing

DOI: 10.17489/biohun/2010/1/1

Biological dose summation of intensity-modulated arc therapy and image-guided high-dose-rate interstitial brachytherapy in intermediate- and high-risk prostate cancer

Purpose: To present an alternative method for summing biologically effective doses of intensity-modulated arc therapy (IMAT) as teletherapy (TT), with interstitial high-dose-rate (HDR) brachytherapy (BT) boost in prostate cancer. Total doses using IMAT boost was compared with BT boost using our method. Material and methods: Initially, 25 IMAT TT plus interstitial HDR-BT plans were included, and additional plans using IMAT TT boost were created. The prescribed dose was 2/44 Gy to the whole pelvis, 2/60 Gy to the prostate and seminal vesicles, and 1 x 10 Gy BT or 2/18 Gy IMAT TT to the prostate. Teletherapy computed tomography (CT) was registered with ultrasound (US) of BT, and the most exposed volume of critical organs in BT were identified on these CT images. The minimal dose of these from IMAT TT was summed with their BT dose, and these EQD(2) doses were compared using BT vs. IMAT TT boost. This method was compared with uniform dose conception (UDC). Results: D-90 of the prostate was significantly higher with BT than with IMAT TT boost: 99.3 Gy vs. 77.9 Gy, p = 0.0034. The D-2 to rectum, bladder, and hips were 50.3 Gy vs. 76.8 Gy (p = 0.0117), 64.7 Gy vs. 78.3 Gy (p = 0.0117), and 41.9 Gy vs. 50.6 Gy (p = 0.0044), while D-0.1 to urethra was 96.1 Gy vs. 79.3 Gy (p = 0.0180), respectively. UDC overestimated D-2 (rectum) by 37% (p = 0.0117), D-2 (bladder) by 5% (p = 0.0214), and underestimated D-0.1 (urethra) by 1% (p = 0.0277). Conclusions: Based on our biological dose summation method, the total dose of prostate is higher using BT boost than the IMAT. BT boost yields lower rectum, bladder, and hips doses, but higher dose to urethra. UDC overestimates rectum and bladder dose and underestimates the dose to urethra

Comparative dosimetrical analysis of intensity-modulated arc therapy, CyberKnife therapy and image-guided interstitial HDR and LDR brachytherapy of low risk prostate cancer

Background: The objective of the study was to dosimetrically compare the intensity-modulated-arc-therapy (IMAT), CyberKnife therapy (CK), single fraction interstitial high-dose-rate (HDR) and low-dose-rate (LDR) brachytherapy (BT) in low-risk prostate cancer. Materials and methods: Treatment plans of ten patients treated with CK were selected and additional plans using IMAT, HDR and LDR BT were created on the same CT images. The prescribed dose was 2.5/70 Gy in IMAT, 8/40 Gy in CK, 21 Gy in HDR and 145 Gy in LDR BT to the prostate gland. EQD2 dose-volume parameters were calculated for each technique and compared. Results: EQD2 total dose of the prostate was significantly lower with IMAT and CK than with HDR and LDR BT, D90 was 79.5 Gy, 116.4 Gy, 169.2 Gy and 157.9 Gy (p < 0.001). However, teletherapy plans were more conformal than BT, COIN was 0.84, 0.82, 0.76 and 0.76 (p < 0.001), respectively. The D2 to the rectum and bladder were lower with HDR BT than with IMAT, CK and LDR BT, it was 66.7 Gy, 68.1 Gy, 36.0 Gy and 68.0 Gy (p = 0.0427), and 68.4 Gy, 78.9 Gy, 51.4 Gy and 70.3 Gy (p = 0.0091) in IMAT, CK, HDR and LDR BT plans, while D0.1 to the urethra was lower with both IMAT and CK than with BTs: 79.9 Gy, 88.0 Gy, 132.7 Gy and 170.6 Gy (p < 0.001). D2 to the hips was higher with IMAT and CK, than with BTs: 13.4 Gy, 20.7 Gy, 0.4Gy and 1.5 Gy (p < 0.001), while D2 to the sigmoid, bowel bag, testicles and penile bulb was higher with CK than with the other techniques. Conclusions: HDR monotherapy yields the most advantageous dosimetrical plans, except for the dose to the urethra, where IMAT seems to be the optimal modality in the radiotherapy of low-risk prostate cancer

Biological dose summation of intensity-modulated arc therapy and image-guided high-dose-rate interstitial brachytherapy in intermediate and high risk prostate cancer

Purpose: To present an alternative method for summing biologically effective doses of intensity-modulated arc therapy (IMAT) as teletherapy (TT), with interstitial high-dose-rate (HDR) brachytherapy (BT) boost in prostate cancer. Total doses using IMAT boost was compared with BT boost using our method. Material and methods: Initially, 25 IMAT TT plus interstitial HDR-BT plans were included, and additional plans using IMAT TT boost were created. The prescribed dose was 2/44 Gy to the whole pelvis, 2/60 Gy to the prostate and seminal vesicles, and 1 x 10 Gy BT or 2/18 Gy IMAT TT to the prostate. Teletherapy computed tomography (CT) was registered with ultrasound (US) of BT, and the most exposed volume of critical organs in BT were identified on these CT images. The minimal dose of these from IMAT TT was summed with their BT dose, and these EQD(2) doses were compared using BT vs. IMAT TT boost. This method was compared with uniform dose conception (UDC). Results: D-90 of the prostate was significantly higher with BT than with IMAT TT boost: 99.3 Gy vs. 77.9 Gy, p = 0.0034. The D-2 to rectum, bladder, and hips were 50.3 Gy vs. 76.8 Gy (p = 0.0117), 64.7 Gy vs. 78.3 Gy (p = 0.0117), and 41.9 Gy vs. 50.6 Gy (p = 0.0044), while D-0.1 to urethra was 96.1 Gy vs. 79.3 Gy (p = 0.0180), respectively. UDC overestimated D-2 (rectum) by 37% (p = 0.0117), D-2 (bladder) by 5% (p = 0.0214), and underestimated D-0.1 (urethra) by 1% (p = 0.0277). Conclusions: Based on our biological dose summation method, the total dose of prostate is higher using BT boost than the IMAT. BT boost yields lower rectum, bladder, and hips doses, but higher dose to urethra. UDC overestimates rectum and bladder dose and underestimates the dose to urethra

A prosztatarák kezelésében alkalmazott besugárzási technikák vizelési képességre gyakorolt korai hatása = Early effects of different irradiation techniques used in the treatment of prostate cancer on urination

Összefoglaló. Bevezetés: A prosztatarák kezelésében jelentős szerepet kapnak a különböző sugárterápiás eljárások. Ennek ellenére a vizelési képességre gyakorolt, rövid és hosszú távú mellékhatásaikat objektív vizsgálómódszerrel igen kevés tanulmányban vizsgálták. Célkitűzés: Arra a kérdésre kerestük a választ, hogy hogyan változik a korai vizelési képesség a különböző sugárterápiás eljárások során. Módszerek: A vizsgálatunkban meghatározott protokoll szerint a kezelés előtt minden bevont beteggel IPSS-t (nemzetközi prosztatatünet-értékelő lap) töltettünk ki, illetve uroflow (vizeletáramlási) vizsgálatot végeztünk, suprapubicus ultrahanggal meghatározott mictiós residuum méréssel kiegészítve. A sugárkezelés befejezésétől számított 4-6 héten belül ismételten elvégeztük ezeket a vizsgálatokat, melyekbe összesen 26 beteget vontunk be. A kezelési modalitások szerint 6, kis dózisteljesítményű (low-dose rate; LDR) brachytherapiában, 5, nagy dózisteljesítményű (high-dose rate; HDR) brachytherapiában, 12, Cyberknife (CK) készüléken extrém hipofrakcionált sugárkezelésben és 3, lineáris gyorsítón (LINAC) mérsékelten hipofrakcionált sugárkezelésben részesített prosztatarákos beteget választottunk be. A kezelések hasonlósága miatt az LDR- és a HDR-csoportot együttesen brachytherapiás csoportként (BTCS), a CK- és a LINAC-csoportot teleterápiás csoportként (TTCS) vizsgáltuk. Eredmények: A BTCS betegeinél az IPSS- és az uroflow paraméterek korai romlása (IPSS irritatív panaszok: p = 0,003, IPSS obstruktív panaszok: p = 0,011, maximális áramlás: p = 0,003, átlagos áramlás: p = 0,006) szignifikánsnak bizonyult, a TTCS-ban mindösszesen az IPSS irritatív tünetekben volt kimutatható eltérés (p = 0,011). Következtetés: A sugárterápiás modalitás kiválasztása előtt javasolható az uroflow és az IPSS-vizsgálat elvégzése. Eredményeink alapján azoknál a betegeknél, akiknél a kezelés előtt középsúlyos vagy súlyos dysuriás vizelési panaszok állnak fenn, a brachytherapia helyett teleterápiás módszerek alkalmazását javasoljuk, amelyek kevésbé rontják a betegek korai vizeletürítési képességét. Orv Hetil. 2021; 162(33): 1328-1334.Various radiotherapy procedures are applied in the treatment of prostate cancer. Nevertheless, their early and late side effects measured by uroflow and residual volume measurements have not been studied extensively.We investigated by objective methods the early changes of urination ability after different radiotherapy procedures.According to the protocol defined in our study, all patients had their IPSS (international prostate symptom score) determined, as well as their uroflow examinations and measurements of their residual urine via suprapubic ultrasound, carried out before treatment. These tests were then repeated at 4-6 weeks after the end of their radiotherapy. A total of 26 patients were included in the study. 6 patients were treated with low-dose rate (LDR) brachytherapy and 5 patients with high-dose rate (HDR) brachytherapy, 12 patients with Cyberknife (CK) using extreme hypofractionation and 3 patients with moderately hypofractionated radiotherapy with a linear accelerator (LINAC). Due to the similarity of the treatments, the LDR and HDR groups together were also studied as brachytherapy group and the CK and LINAC patients as teletherapy group.We found that the early deterioration of IPSS and uroflow parameters after brachytherapy were significant (IPSS irritative symptoms: p = 0.003, IPSS obstructive symptoms: p = 0.011, maximum flow: p = 0.003, mean flow: p = 0.006), while in teletherapy only the IPSS irritative symptoms worsened significantly (p = 0.011).Based on our results, we suggest to perform uroflow examination and IPSS test before selecting therapeutic modality for patients with prostate cancer. In patients with moderate or severe urinary complaints before the treatment, we recommend to use teletherapy rather than brachytherapy. Orv Hetil. 2021; 162(33): 1328-1334