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

Does inverse planning improve plan quality in interstitial high-dose-rate breast brachytherapy?

Purpose: To investigate the effect of input parameters for an inverse optimization algorithm, and dosimetrically evaluate and compare clinical treatment plans made by inverse and forward planning in high-dose-rate interstitial breast implants. Material and methods: By using a representative breast implant, input parameters responsible for target coverage and dose homogeneity were changed step-by-step, and their optimal values were determined. Then, effects of parameters on dosimetry of normal tissue and organs at risk were investigated. The role of dwell time modulation restriction was also studied. With optimal input parameters, treatment plans of forty-two patients were re-calculated using an inverse optimization algorithm (HIPO). Then, a pair-wise comparison between forward and inverse plans was performed using dose-volume parameters. Results: To find a compromise between target coverage and dose homogeneity, we recommend using weight factors in the range of 70-90 for minimum dose, and in the range of 10-30 for maximum dose. Maximum dose value of 120% with a weight factor of 5 is recommended for normal tissue. Dose constraints for organs at risk did not play an important role, and the dwell time gradient restriction had only minor effect on target dosimetry. In clinical treatment plans, at identical target coverage, the inverse planning significantly increased the dose conformality (COIN, 0.75 vs. 0.69, p < 0.0001) and improved the homogeneity (DNR, 0.35 vs. 0.39, p = 0.0027), as compared to forward planning. All dosimetric parameters for non-target breast, ipsilateral lung, ribs, and heart were significantly better with inverse planning. The most exposed small volumes for skin were less in HIPO plans, but without statistical significance. Volume irradiated by 5% was 173.5 cm(3) in forward and 167.7 cm(3) in inverse plans (p = 0.0247). Conclusions: By using appropriate input parameters, inverse planning can provide dosimetrically superior dose distributions over forward planning in interstitial breast implants

A magyar sugárterápia jelenlegi helyzetének bemutatása

The purpose of the study is to report the status of Hungarian radiotherapy (RT). In the 13 centers 84 radiation oncologists, 19 residents, 66 physicists and 231 radiotherapy technologists work, and 40 megavoltage units (38 linear accelerators, 2 cobalt units) are in use. HDR afterloader is available in all and CT-simulator in all but one centers. In 2017 33,024 patients received RT, 22,236 were irradiated with MV beams, 1,406 with BT and 9,382 with orthovoltage X-ray. Main indications for BT were gynecological tumors (75%), HDR prostate implants were performed in 3 centers. Due to the recent infrastructural developments the number of patients receiving modern RT increased, but in order to fulfil the international recommendations additional linear accelerators have to be installed along with the replacement of the out of date equipment. From professional point of view further developments are warranted in Budapest

III. Emlőrák Konszenzus Konferencia – Sugárterápiás irányelvek

The radiotherapy expert panel revised and updated the radiotherapy (RT) guidelines accepted in 2009 at the 2nd Hungarian Breast Cancer Consensus Conference based on new scientific evidence. Radiotherapy of the conserved breast is indicated in ductal carcinoma in situ (St. 0), as RT decreases the risk of local recurrence by 60%. In early stage (St. I-II) invasive breast cancer RT remains a standard treatment following breast conserving surgery. However, in elderly (>/=70 years) patients with stage I, hormone receptor positive tumour hormonal therapy without RT can be considered. Hypofractionated (15x2.67 Gy) whole breast irradiation and for selected cases accelerated partial breast irradiation are validated treatment alternatives of conventional (25x2 Gy) whole breast irradiation. Following mastectomy RT significantly decreases the risk of locoregional recurrence and improves overall survival of patients having 1 to 3 (pN1a) or >/=4 (pN2a, pN3a) positive axillary lymph nodes. In selected cases of patients with 1 to 2 positive sentinel lymph nodes axillary dissection can be omitted and substituted with axillary RT. After neoadjuvant chemotherapy (NAC) followed by breast conserving surgery whole breast irradiation is mandatory, while after NAC followed by mastectomy locoregional RT should be given in cases of initial stage III-IV and ypN1 axillary status

Financial stability challenges in candidate countries - managing the transition to deeper and more market-oriented financial systems.

This paper reviews financial stability challenges in the EU candidate countries Croatia, Turkey and the former Yugoslav Republic of Macedonia. It examines the fi nancial sectors in these three economies, which, while at very different stages of development and embedded in quite diverse economic settings, are all in a process of rapid financial deepening. This manifests itself most clearly in the rapid pace of growth in credit to the private sector. This process of financial deepening is largely a natural and welcome catching-up phenomenon, but it has also increased the credit risks borne by the banking sectors in the three economies. These credit risks are compounded by the widespread use of foreign currency-denominated or -indexed loans, leaving unhedged bank customers exposed to potential swings in exchange rates or foreign interest rates. Moreover, these financial risks form part of a broader nexus of vulnerabilities in the economies concerned, in particular the external vulnerabilities arising from increasing private sector external indebtedness. That said, the paper also fi nds that the authorities in the three countries have taken several policy actions to reduce these fi nancial and external vulnerabilities and to strengthen the resilience of the financial sectors. JEL Classification: F32, F41, G21, G28.Europe, banking sector, vulnerability indicators, capital inflows, emerging markets.

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 &lt; 0.001). However, teletherapy plans were more conformal than BT, COIN was 0.84, 0.82, 0.76 and 0.76 (p &lt; 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 &lt; 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 &lt; 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

Image guided high-dose-rate brachytherapy versus volumetric modulated arc therapy for head and neck cancer

Background The aim of the study was to present dosimetric comparison of image guided high-dose-rate brachytherapy (IGBT) with volumetric modulated arc therapy (VMAT) for head and neck cancer regarding conformity of dose distribution to planning target volume (PTV) and doses to organs at risk (OARs). Patients and methods Thirty-eight consecutive patients with T1-4 mobile tongue, floor of mouth and base of tongue cancer treated with IGBT were selected. For these patients additional VMAT treatment plans were also prepared using identical computed tomography data. OARs and PTV related parameters (e.g. V98, D0.1cm3, Dmean, etc.) were compared. Results Mean V98 of the PTV was 90.2% vs. 90.4% (p > 0.05) for IGBT and VMAT, respectively. Mean D0.1cm3 to the mandible was 77.0% vs. 85.4% (p 0.05). Dmean to ipsilateral and contralateral submandibular glands was 16.4% vs. 21.9% (p > 0.05) and 8.2% vs. 16.9% (p < 0.05), respectively. Conclusions Both techniques showed excellent target coverage. With IGBT dose to normal tissues was lower than with VMAT. The results prove the superiority of IGBT in the protection of OARs and the important role of this invasive method in the era of new external beam techniques