There are a number of studies supporting the value of MRS for prostate cancer diagnosis and treatment plan- ning. Studies of MRS to direct prostate biopsy show that the use of combination MRI and MRS may reduce the rate of false-negative biopsies and hence decrease the need for more extensive biopsy protocols and/or repeated biopsy procedures . The combination of volumetric data from MRS and anatomical display of MR improves the evaluation of extracapsular extension (ECE) . MRS can diagnose metabolic atrophy which is indicative of successful treatment because the growth of normal or abnormal cells cannot occur without meta- bolism. Thus MRS also has the potential to be an earlier indicator for resolution of local disease than the PSA nadir [5,6]. The ratio of (choline + creatine)/citrate from MRS examination was also found to correlate with the Gleason grade from biopsy, which in most cases corre- lates to the aggressiveness of prostate cancer .
dose-escalation study by Hoskin et al. has compared HDR-B monotherapy with 34 Gy in four fractions, 36 Gy in four frac- tions, and 31.5 Gy in three fractions . Computed tomog- raphy was performed before the second and fourth fraction and catheters were readjusted if they were dislocated > 5 mm . We have used the 4 × 9.5 Gy fractionation scheme with ultrasound-based postplanning. Gold markers and radiopaque- labeled reference applicators were used for X-ray-based setup and position control between the single fractions. Toxicity rates have been previously described , being comparable to the two existing studies using the same fractionation schedule [16, 18]. We observed substantial interfractional applicator dis- locations, predominantly in the caudad direction, peaking be- fore the second fraction, with the mean value being –13.1 mm (range, –36 to 0 mm). This can be explained by the postimplant prostate bleeding and/or edema with enlargement of the pros- tate as it has been described by others . Prostate edema, subsequent prostate volume changes, and changes of dosimet- ric parameters after LDR-B were extensively described . In our study, dislocations of the applicators ≤ 2 mm were toler- ated, dislocations > 2 mm were corrected. This is a relatively low action level. Thus, applicators had to be readjusted in 91% of the patients. Since readjustment of the applicators requires intraprostatic manipulation which could potentially be associ- ated with a trauma to the prostate, urethra or bladder, we were interested if readjustments > 10 mm were associated with in- creased GU toxicity. However, we found no association with acute or late GU toxicity. Moreover, there was no association with the PTV size or the number of needles used. One limita- tion of our study is the relatively short median follow-up with no patient experiencing biochemical relapse. If the follow-up matures, it will be interesting to compare the biochemical out- come data with incidence and magnitude of applicator disloca- tions to exclude insufficient PTV dose covering.
MRI-guidedbrachytherapy remains attractive concept in both in LDR and HDRbrachytherapy for prostate cancer. However, it is hard to predict how the role of MRI will entails in HDRbrachytherapy given very high level of complexity and intense resource utilisation associated with interventional MRI. Added benefit of MRI in whole gland boost might be less critical compared with role of MRI guidance in focal treatment (either for salvage after previous EBRT or targeted dose escalation to dominant intraprostatic lesion or upfront partial gland treatment). Recent study from Princess Margaret Cancer Centre prostatebrachytherapy group presented dosimetric feasibility of focal dose-escalated HDR monotherapy. In this dosimetric study it was found feasible to escalate the dose both to intraprostatic PTV (33-36 Gy) and GTV (40 Gy) in two fractions respecting predefined OAR constraints. Additionally, in almost half of the investigated cases it was possible to achieve single-dose treatment of 24 Gy to PTV (182). Although focal therapy concept definitively needs to be assessed in rigorously conducted prospective trial, these preliminary dosimetric results remain encouraging. Potential candidates for focal approach would probably be patients with unifocal gross disease (MRI-defined lesion) in lower risk group.
Salvage HDR BT is a safe and effective treat- ment option for recurrent prostate cancer (3–6). Lee et al. analyzed the results of 21 patients who were treated with salvage HDR BT because of recurrence in prostate after external beam ra- diotherapy. After pathologic confirmation of locally recurrent disease, all patients were treat- ed with 36 Gy in six fractions using two trans- rectal ultrasound-guidedHDRprostate im- plants, separated by 1 week. 18 patients reported Grade 1 to 2 genitourinary symptoms within 3 months after salvage treatment, three patients developed Grade 3 genitourinary toxicity. The maximum observed gastrointestinal toxicity was Grade 2. The 2-year biochemical control after re- currence was 89% (4).
Imaging systems for prostate cancer require high spatial resolution, the ability to view soft tissue and implanted seeds, and fast response time to resolve the seeds before, during and after treatment. Intraoperative planning provides 3D anatomical informa- tion during therapy and enables accurate seed positioning and live time verification of dosimetric outcomes . The major imaging technique used is an ultrasound-guided approach (used in LDR and HDR) and provides 3D reconstruction of the Clinical Tar- get Volume (CTV) for planning. HDR afterloading catheters are spaced evenly within the CTV and fixed using a template. An alternative imaging method for verification of treatment planning are postoperative CT scans taken after recovery from a procedure to allow more detailed planning before treatment. Imaging system are used to avoid sub- optimal dosimetry, which can be caused by prostatic oedema (tissue expansion) and can alter the relation between the prostate gland, organs at risk and the implanted catheters. Thus verification using catheter measurements, fluoroscopy and repeat scanning before each fraction is very important to correct these issues .
to the shape of the tumour. This is known as intensity modulated radiation therapy (IMRT). The desired dose distribution in the tumour is defined in a treatment planning system, which then optimises beam delivery to achieve this distribution while minimis- ing exposure to sensitive organs and healthy tissues in general. The treatment plan created using this computer-assisted inverse method conforms more precisely to the target geometry compared to traditional 3D-CRT. However, IMRT assumes that the target geometry is time-invariant, while in practice organs are continuously in motion due to respiration and other involuntary movements; the patient may also not be pre- cisely physically registered to exactly the same position as during the pre-irradiation imaging procedure. To reduce the impact of geometry changes between treatment plan and beam delivery, imaging can be performed concurrently with treatment, allowing the treatment plan to be adjusted in real time. This technique is known as image guided radiation therapy (IGRT). A further refinement is to use continuous rather than discrete adjustment of beam orientation, shape and intensity - this is known as volumetric modulated arc therapy (VMAT). IGRT and VMAT are the state of the art in external beam radiation therapy.
CT-guided BT planning represents one of the earliest attempts to use volumetric imag- ing to accurately identify targets and OARs, as well as plan radioactive source posi- tions, with good outcomes; Koutrouvelis et al. (2000) reported prostate-specific antigen (PSA) <2 ng/mL in 90 % of patients (n = 301) at median 26 month follow-up after being treated with permanent implant CT-guided BT (Koutrouvelis et al. 2000). Intra- operative TRUS-guided BT is rapidly growing in adoption largely due to its lower cost, widespread availability, and real-time guidance, and has allowed implant guidance dur- ing the BT procedure in addition to target localization. Stone et al. (2007), pioneers of the TRUS-guided permanent implant approach, reported excellent long-term toxic- ity outcomes of 325 patients (Stone and Stock 2007; Crook et al. 2011). TRUS-guided BT is now the recommended standard of care for prostate BT by both ABS and GEC- ESTRO guidelines for both LDR and HDR implants (Davis et al. 2012; Yamada et al. 2012; Hoskin et al. 2013). Despite these many advantages, significant TRUS artifact still make identification of the target and OARs highly subjective (Fig. 5) (Xue et al. 2006; Solhjem 2004). Further identification of DILs for dose escalation is simply not feasible using TRUS guidance alone, and a workflow incorporating mpMRI fusion with TRUS imaging is commonly required.
We attempted to control local micrometastatic progression through treatment of the pelvic lymph nodes using an initial course of IMRT. The patient did have distant metastatic progres- sion four months following adjuvant radiation. However, she did experience resolution of gross tumor, with no evidence of local progression. For this patient, brachytherapy was the ideal treatment solution because of the location of the tumor, which was near the proximal vagina, and because residual tumor disease requires high doses of radiation. Interstitial HDRbrachytherapy catheter placement and CT/MR planning allowed for dose optimization to the primary tumor. The patient tolerated the procedure well, reporting no postoperative morbidity and minimal acute radiation related side effects.
Purpose: Curative radiation therapy is an established treatment option for non-surgical patients with early-stage endometrial carcinoma. Dosimetric analyses were performed using a single tan- dem, double tandem, Heyman capsules, and an inflatable intrauterine balloon to assess the dose homogeneity and conformality in the definitive treatment of inoperable endometrial cancer. Me- thods and Materials: Patients’ informed-consent was obtained. Dosimetric analyses were performed using four different after-loading applicators to assess the dose homogeneity and conformality of isodose to the three-dimensional (3-D) shape of the target volume (uterus) based on CT data in four patients (n = 4). The single tandem and double tandems were standard Fletcher-type (Nucle- tron Corporation, Columbia, MD). Heyman capsules were the disposable after-loading type (Radia- tion Products Design, Inc., Albertville, MN). The inflatable balloon with a central bi-lumen catheter was the Mammo Site Radiation Therapy System (Proxima Therapeutics, Alpharetta, GA) that is currently used for local breast brachytherapy. Treatment planning and dosimetric analyses for all four techniques were done with HDR PLATO Brachytherapy (v14.2.3) Software (Nucletron Corpo- ration). Results: The average dose gradient within the target (uterine wall) is highest with the tandem methods, followed by Heyman capsules. The intrauterine balloon method showed the least dose gradient across the uterine wall. The corresponding average homogeneity indices were 3.81, 3.83, 2.97, 2.50 for single tandem, double tandem, Heyman capsules, and intrauterine bal- loon respectively. Conclusions: The intra-uterine inflatable balloon appears to have the best over- all dosimetric advantages for the treatment of the uterine wall. Furthermore, the potential ease of use, shorter time of applicator placement, and better patient comfort warrant further investiga- tion and subsequent clinical implementation.
In higher risk patients there is interest in escalating the dose delivered to the DIL while treating the whole gland. Treatments that escalate dose to the DIL in an attempt to increase tumour control have been investigated using intensity modulated radiotherapy (IMRT), stereotactic radiotherapy and both LDR and HDRbrachytherapy but there is no consensus on the best approach to achieve these treatments (18). For focal boost dose escalation with whole gland treatment, very large numbers of patients would be required to achieve a statistically significant improvement in actual or biochemical relapse free survival compared to standard whole gland treatment. Therefore published studies have focused on demonstrating that focal boost dose escalation can be achieved without increasing treatment related toxicities. A recent systematic review of these studies covering external beam and brachytherapy treatments concluded that toxicity rates were low but the boost doses achieved were modest, and there was too much difference between the methodologies used in individual studies to allow more robust conclusions to be drawn (18). Because of this relative lack of evidence, the focal boost treatments described in this work were introduced as a pilot study. Meanwhile a prospective randomized trial is also underway (22).
Many factors affect its readings like the stability of produced signal, the availability, fading rate which should be lower than 5% per month, glow curves must be simple and a plain anneal heating cycle. Some activators (impurities) can be added to increase its sensitivity of tissue equivalent material to increase the number of traps which emit more light during TL process then increase its efficiency. The need of background signal variation is to help measuring the low dose threshold (< 0.1mGy) with high accuracy. Ideal dosimeter has a linear response for doses which is not affected from any dose rate but using different angles can affect its response . The interest is increased in the improvement of the accuracy of dosimetry in brachytherapy purposes by the use of remote afterloading, CT scan data, MRI for volume definition, dose calculation by Monte Carlo methods, the use of low energy gamma radiation sources, and the possibility of real time biological and dosimetric optimization. All of these led improved the accuracy of dose distributions and dose calculations in tissue equivalent materials to modify the algorithms . The sensitivity of TLD varies with photon energy; it is the response per unit dose. TLD sensitivities varies with depth, it have the values 1.08, 1.06, 1.05, 1.02, and 1.00 for depth of 10, 7, 5, 3, and 1 cm respectively .
it and if the capsule (edges) of the prostate gland is intact. This is important because prostate cancer that is bulging against or through the prostate capsule may not be effectively treated with the seeds. There is often a number of weeks wait for MRI scans but this is clinically acceptable for low risk prostate cancer. Your team will arrange for your scan to be done as soon as possible. Some patients will also require an Isotope Bone Scan to assess for potential prostate cancer spread to the bones. If you are unsure whether you need any of these scans please ask your doctor or your specialist nurse.
HDR dosimetry is prospective (done before source de- livery), consistent, and reliable because it is not impacted by setup errors, interfraction and intrafraction organ mo- tion, prostate swelling, or shrinkage during treatment deliv- ery. Furthermore, target coverage is verifiable through pretreatment image guidance designed to avoid unrecog- nized ‘‘dwell position displacement’’. Dose modulation of the stepping source can compensate for catheter spacing and volume discrepancies by using ‘‘optimization’’ pro- grams so that dose painting and dose sculpting can be done for dose adjustments within the target boundaries. Such ca- pacities make HDR an excellent choice for monotherapy or for EBRT boost; and in properly selected cases, it can be used to reduce or eliminate radiation to parts of the prostate (focal therapy or dose de-escalation). These measures may enhance the therapeutic index by delivery of dose in pro- portion to the extent and severity of the disease, and it can reduce morbidity by limiting dose to normal structures. The excellent results of HDRprostatebrachytherapy coupled with the radiobiological advantage of higher doses per fraction especially in tumors with low alpha/beta have prompted clinical trials of stereotactic body radiation ther- apy (SBRT) to deliver the full course of external beam ther- apy in 4e6 fractions like HDR (58e65) . Fuller et al. (66)
Endoluminal brachytherapy is an effective treatment that helps clear obstructed airways with high rates of success in achieving local remission, with  reporting 73% of patients achieving remission. However, because of its nature, it can only target tumours that are around or very close to the main bronchi  and studies often indicate very low long term survival rates , although it is important to mention that in most cases, patients undergoing endoluminal brachytherapy are those whose tumours are considered inoperable due to their advanced stage and/or poor health. Compared to external beam radiation (EBR), brachytherapy offers a similar level of effectiveness, with reduced fatigue and nausea, but results in increased chest pain and dyspnoea; however, significant complications are rare in either case . In general, brachytherapy does not necessarily offer a better alternative to external beam radiation; however, especially for patients who have undergone radiation before, brachytherapy is a safer choice due to the lower amounts of radiation that surrounding tissues are exposed to .
In Europe as well as in North America, carcinoma of the prostate (CaP) is the most frequent cancer in men before lung cancer [1,2]. Moreover, its incidence has been in- creasing during recent decades and continues to rise. Thanks to efforts toward early diagnosis, CaP is mostly diagnosed at an early stage. Until now, comparison of different treatments according to long-term oncological results has been controversial , putting functional as- pects at the forefront in decision counseling. Erectile dysfunction (ED) is a major preoccupation for CaP pa- tients, especially younger ones. In a series of men treated for localized CaP 12 to 24 months previously, Bokhour et al. found that ED affected not only the quality of sex- ual intimacy, but also everyday interaction with women, sexual imaging and fantasy life, and manliness percep- tion . A meta-analysis of 54 articles concluded that the predicted probability of maintaining erectile function was 0.76 after prostatebrachytherapy (PB), 0.60 after PB plus external beam radiotherapy, 0.55 after external beam radiotherapy, 0.34 after nerve-sparing radical pros- tatectomy and 0.25 after standard radical prostatectomy . However none of the articles analyzed were random- ized controlled trials, some of the studies did not reflect current standards of treatment and none of the PB studies had a follow-up longer than 2 years. The latter point is cru- cial in view of the possibility of delayed deterioration of erectile function following radiation treatments [6,7]. How- ever, so far, observations of changes over time of the preva- lence of ED after PB remain controversial. Stock et al. found that the proportion of potent men decreased over time following PB (79% at 3 years, 59% at 6 years) . Valicenti et al. observed that after PB, one patient on two had ED, but that dysfunction resolved within one year after treatment . Finney et al. found no significant correlation between the proportion of men with ED and time since implantation, with a median follow-up of 2.5 years .
study evaluating prostate distortion with erMRI (36) . However, to the authors’ knowledge, our study is the first to directly evaluate erMRI for prostatebrachytherapy pre- planning and compare it with other imaging modalities. From our analysis, we conclude that erMRI is not ideal for treatment planning, because the resulting anatomic distortion required nonstandard, often asymmetric loading patterns, and also often required needles to track through the rectum to achieve adequate peripheral zone coverage. Given the susceptibility of brachytherapy treatment plan- ning to minor changes in target delineation, the distortion in prostate volume and dimensions with the endorectal coil could result in major changes in the accuracy of dose delivery; because the prostate will return to its normal shape after the procedure, the erMRI-based plan does not accurately represent the anatomy that exists for the duration of treatment delivery. Notably, we used erMRI images for the present study that were obtained for the purpose of ruling out extraprostatic extension or seminal vesicle involvement, and were thus optimized for this purpose. erMRI may be more useful for treatment planning if it was optimized for treatment planning, such as minimizing anatomic distortion by filling the balloon less, and this represents an interesting direction for future study.
practice of Low Dose Rate (LDR) ICBT was replaced by High Dose Rate (HDR) ICBT in most of the countries of the world  . Though, some practical gains such as shorter treatment time, less radiation hazard to health care givers, by HDR ICBT, still there are concerns about late toxicity of large dose per fraction  . In treatment of cancer cervix ICBT with HDRbrachytherapy is being performed since many decades, but there is no consensus about an optimal fractionation schedule available in English literature. American Brachytherapy Society (ABS) recommends that individual fraction size should be less than 7.5 Gy per fraction and number of fractions should range from four to eight depending on fraction size  . The current study was undertaken to compare the two regimes of brachytherapy in cervical cancer in terms of local control, disease-free survival, overall survival and toxicity—6Gy per fraction in four fractions (Control ArmA) and 7.5Gy per fraction in three fractions (Study Arm B).
The sonographic fi nding of the classic hypoechoic peripheral zone lesion has a sensitivity of cancer detection of 85.5%, specifi city of 28.4%, positive predictive value of 29%, negative predictive value of 85.2% and overall accuracy of 43%. The prevalence of isoechoic or nearly invisible prostate cancers on TRUS to ranges from 25 to 42%. To date, no biologic differences have been noted between isoechoic and hypoechoic prostate cancers.
Recent studies have suggested that when more than one of the adverse risk factors viz., young age, premeno- pausal status, tumour size, tumour grade, lymphovascular invasion, margin status, nodal ration, estrogen receptor status, tumour subtype, 21-gene recurrence score, and the genomic predictive index are present in the setting of nodal involvement, more aggressive locoregional man- agement is warranted [11,12]. Even as the debate con- tinues, the technological development in External Beam Radiotherapy (EBRT) like Intensity Modulated Radio- therapy (IMRT), Respiratory Gated Radiotherapy, and Volumetric Modulated Radiotherapy (VMAT), and Im- age-Guided Radiotherapy (IGRT), has made it now pos- sible to deliver radiation to Planned Target Volumes (PTV) with minimal setup errors and with acceptable dose coverage, while sparing the organs at risk (OARs). Moreover, efforts are also made to develop atlas-based guidelines for implementing uniformity in delineation of the target and critical structures which are expected to minimize the interpersonal variations . In PMRT, by implementing these technologies and using electrons- photon combinations, it is expected to bring down the pulmonary or cardiac toxicities [14-18].
In this study, we fabricated a Cerenkov fiber-optic dosimeter (CFOD) without any scintillator to measure Cerenkov radiation signals owing to gamma-rays. The relative depth dose (RDD) distri- butions of Ir-192 HDRbrachytherapy source were obtained by using the CFOD based on a subtrac- tion method and the RDD curve was compared with the simulation result of Monte Carlo N-particle extended transport code (MCNPX). Finally, we demonstrated that the CFOD can be used to meas- ure real-time dose information for HDRbrachytherapy.