Comparative performance analysis of 2D and 3D gamma metrics for patient specific QA in VMAT using Octavius 4D with 2D-Array 1500

INTRODUCTION

Gamma pass percentage (GPP) is the predominant metric used for Patient Specific Quality Assurance (PSQA) in radiation therapy. The dimensionality of the measurement geometry in PSQA has evolved from 2D planar to 3D planar, and presently to state-of-the-art 3D volumetric geometry. We aim to critically examine the performance of the three-dimensional gammas vis-à-vis the older gamma metrics of lower dimensionality to determine their mutual fungibility in PSQA, using clinically approved Volumetric Arc Therapy (VMAT) plans.

METHODS AND MATERIALS

Gamma pass percentages derived from PSQA for VMAT plans using Octavius 4D phantom with 2D-Array 1500 and its proprietary software were recorded. 2D planar, 3D planar, and 3D volumetric gamma pass percentages were retrospectively extracted for multiple treatment plans at three sites, using three acceptance limits, and for two modes of normalization. The differences in mean pass percentages, and the pairwise correlation between geometries were calculated within limits of statistical significance.

RESULTS

A significant increase in mean pass rates was observed from 2D planar to 3D planar geometries. The difference was less pronounced from 3D planar to 3D volumetric. 2D planar v/s 3D planar showed a significant degree of correlation among themselves, which was not seen against most of the 3D volumetric pass rates.

CONCLUSION

The mean gamma pass rates show conclusive evidence of the benefits of shifting from 2D planar to higher dimensions measurement geometries, but the benefits of using 3D volumetric compared to 3D planar is not always unequivocal. The correlations show mixed results regarding the interdependence of pass percentages at different geometries.

489 Assessing the Impact Of COVID-19 On Head and Neck Cancer Treatment and Preparing for The Next Wave

Introduction

As of 11th of March 2020, the World Health Organization (WHO) declared the novel coronavirus 2019 (COVID-19) a pandemic. It is estimated that urgent cancer referrals have reduced 70-89% across hospitals in England during the COVID-19 pandemic, in addition to reductions in attendance for the different treatment arms. The aim of our investigation is to assess the impact of COVID-19 on MDT outcomes and patients attending/receiving treatment as compared to before for head and neck cancer.

Method

Data was collected retrospectively over a period of 203 days (7th January to 28th July 2020), including 66 patients prior to COVID-19 being declared a pandemic and 116 patients since, at a regional cancer centre. A total of 182 patients undergoing treatment were identified. These patients were assessed by TNM staging, MDT outcomes and final initial treatment intents, which were compared to pre-COVID outcomes.

Results

With respect to MDT outcomes, there was an increase in the number of patients decided for surgery from 10.61% to 23.28% (p = 0.78) during the first wave of the pandemic. Patients decided for radiotherapy and chemotherapy increased by 12.49% and 4.31% respectively. Notably, there was a decrease in further investigations and referrals from 37.88% to 18.10%. Moreover, an increase in palliative treatment intent by 10.55% was noted during the pandemic.

Conclusions

As the UK enters into the next peak of the pandemic, with reduced capacity for elective surgery and outpatient clinics, it is essential to consider its impact on the standard of care delivered to current cancer patients.

Dosimetric analysis of Deep Inspiratory Breath-hold technique (DIBH) in left-sided breast cancer radiotherapy and evaluation of pre-treatment predictors of cardiac doses for guiding patient selection for DIBH

Introduction

The risk of radiotherapy-associated cardiovascular disease has been a concern for decades in breast cancer survivors. The objective of our study is to evaluate the dosimetric benefit of Deep Inspiratory Breath-hold technique (DIBH) on organs-at-risk (OAR) sparing in left-sided breast cancer radiotherapy and to find out pre-treatment predictors of cardiac doses for guiding patient selection for DIBH.

Material and methods

Pre-radiotherapy planning CT scans were done in Free Breathing (FB) and in DIBH [using Active Breathing Coordinator system (ABC™)] in 31 left sided breast cancer patients. 3DCRT plans were generated for both scans. Comparison of anatomical and dosimetric variables were done using paired t test and correlation was evaluated using Pearson correlation. Linear regression was used to get independent predictors of cardiac sparing and Receiver Operating Characteristic (ROC) curve analysis was done to find out the specific threshold of the predictors.

Results

There was a 39.15% reduction in mean heart dose in DIBH compared to FB (2.4 Gy vs 4.01 Gy) (p < 0.001), 19% reduction in maximum Left Anterior Descending (LAD) dose and a 9.9% reduction in ipsilateral lung mean dose (p = 0.036) with DIBH. A significant correlation was observed between reduction in Heart Volume in Field (HVIF) and Maximum Heart Depth (MHD) with reduction in mean heart dose. Reduction in HVIF (ΔHVIF) independently predicted cardiac sparing.

Conclusion

DIBH leads to significant reduction in OAR doses and is suggested for all patients of left-sided breast cancer undergoing radiotherapy. However, HVIF and MHD predicted for cardiac sparing and threshold criteria of ΔHVIF and ΔMHD may be used by centres with high workload to select patients for DIBH.

Choosing a career in radiation oncology in India: A survey among young radiation oncologists

Background

Radiation oncology in India is much debated as a career option to take up. This survey among young radiation oncologists (YROs), the first of its kind, attempts to assess the career expectations and concerns that affect most of us.

Materials and Methods

This survey was conducted using the online survey tool of SurveyMonkey in October 2018. The Association of Radiation Oncologists of India (AROI) members' database was used to send the survey link over E-mail to recipients (AROI life member after 2004).

Results

Out of 1685 invitees, 492 (29.19%) recipients took the survey. Most (69.14%) of the respondents were males who worked as senior residents and junior consultants and employed in private hospitals and state-level teaching institutes. Postspecialization (MD/DNB) experience was mostly <3 years (56.52%). Most of YROs worked in Tier-I city (48.9%) mostly in telecobalt-based facilities. Most of our respondents (73.01%) aspired to work in academic teaching hospital/research institute, and the primary concern was academics/research (39.88%) followed by income (23.31%). There was a similar distribution of respondents with respect to their desire to shift to medical oncology. There was marked dissatisfaction over remuneration, job openings, job security, and poor scope of career improvement. 56.50% of respondents believed that they need to move abroad to improve their quality of life. However, 76.69% of respondents still felt very passionate about their professional choice. Finally, 61.97% of professionals believed that this survey will correctly reflect the present scenario among YROs.

Conclusions

The survey portrays a mixed picture as expected. Major policy changes are required to improve the infrastructure and job opportunities of this profession.

Retrospective study on performance of constancy check device in Linac beam monitoring using Statistical Process Control

AIM

To examine the application of Statistical Process Control (SPC) and Ishikawa diagrams for retrospective evaluation of machine Quality Assurance (QA) performance in radiotherapy.

BACKGROUND

SPC is a popular method for supplementing the performance of QA techniques in healthcare. This work investigates the applicability of SPC techniques and Ishikawa charts in machine QA.

MATERIALS AND METHODS

SPC has been applied to recommend QA limits on the particular beam parameters using the QUICKCHECK webline QA portable constancy check device for 6 MV and 10 MV flattened photon beams from the Elekta Versa HD linear accelerator (Linac). Four machine QA parameters - beam flatness, beam symmetry along gun target direction and left-right direction, and beam quality factor (BQF) - were selected for retrospective analysis. Shewhart charts, Exponentially Weighted Moving Average (EWMA) charts and Cumulative Sum (CUSUM) charts were obtained for each parameter. The root causes for a failure in machine QA were broken down into an Ishikawa diagram enabling the user to identify the root cause of error and rectify the problem subsequently.

RESULTS

Shewhart charts and EWMA charts applied could detect loss in control in one variable in the 6 MV beams and in all four variables in 10 MV beams. CUSUM charts detected offsets in the readings. The Ishikawa chart exhaustively included the possible errors that lead to loss of control.

CONCLUSION

SPC is proven to be effective for detection of loss in control in machine QA. The Ishikawa chart provides the set of probable root causes of machine error useful while troubleshooting.

RAPID IDENTIFICATION OF ABIOTIC STRESS (FROST) IN IN-FILED MAIZE CROP USING UAV REMOTE SENSING

Abstract. Stress in the crop not only decreases the production but can also have devastating consequences for farmers whose life depends upon the healthy crops. In recent time (January 2018) a such abiotic stress event (hoar frost) was experienced at ICAR research complex experimental filed, Ri-Bhoi district of Meghalaya on standing Maize crop. Therefore, remote sensing (Multispectral UAV- Unmanned Aerial Vehicle) technology were used to detect the effect of frost on in-filed Maize crop. Two set of multispectral data (before frost and after frost) with four advanced machine learning techniques viz. Random Forest (RF), Random Committee (RC), Support Vector Machine (SVM) and Artificial Neural Network were employed for detection of stress free crop and stressed crop due to frost. Results revealed that all the four methods of classification could able to identify / detect stress-free vs. stressed crops at satisfactory level. However, among the classifiers RF achieved relatively higher overall accuracy (OA = 86.47%) with Kappa Indexanalysis (KIA = 0.80) and found very cost effective in context of computational cost (time complexity = 0.08 Seconds) to train the model. In addition, we have also recorded the area of each classes and found that after frost stress-free area (36.01% of all over filed) is decreased by 11% in comparison of before frost (25.036% of all over filed). Based on the results we can suggest that the RF ensemble classification method can be used for further other crop classification in order to estimate the yield, detect the condition, monitoring the health etc.

Collaborating to Compete: Blood Profiling Atlas in Cancer (BloodPAC) Consortium

The cancer community understands the value of blood profiling measurements in assessing and monitoring cancer. We describe an effort among academic, government, biotechnology, diagnostic, and pharmaceutical companies called the Blood Profiling Atlas in Cancer (BloodPAC) Project. BloodPAC will aggregate, make freely available, and harmonize for further analyses, raw datasets, relevant associated clinical data (e.g., clinical diagnosis, treatment history, and outcomes), and sample preparation and handling protocols to accelerate the development of blood profiling assays.

Steroid and metabolic hormonal profile of porcine serum vis-à-vis ovarian follicular fluid

Aim:

This study was conducted to understand whether serum level of the steroid and metabolic hormones may be indicative of their level in ovarian follicular fluid (FF) in porcine, and its influence on fertility.

Materials and Methods:

Ovaries from pigs (n=32) of two genetic groups, namely, native (Ghungroo; n=16) and crossbred (Hampshire × Ghungroo; n=16) were collected. Both the genetic groups comprised gilts (n=8) and sows (n=8), and sows were in luteal phase of estrus cycle. FF was aspirated from small, medium and large follicles, and centrifuged for the collection of supernatant for further analysis. Blood samples were collected from the same animals, and serum was separated. Hormones, namely, cortisol, T3, T4 and testosterone were estimated by radioimmunoassay. Two-way ANOVA was used for analysis of data considering genetic background (native or crossbred), stage of reproductive life (gilt or sow), and source of sample (serum or FF) as fixed effects.

Results:

It was observed that all the hormones except cortisol differed significantly (p<0.01) based on genetic background. Stage of reproductive life and source of sample did not affect the studied hormonal level. Within the genetic groups, stage of reproductive life influenced T3 (p<0.01), cortisol (p<0.05) and testosterone (p<0.01) level in crossbred pigs as compared to T3 (p<0.01) only in native pigs. The level of T3 in serum, as well as FF, was higher (p<0.01) in Ghungroo gilts compared to sows. However, a reverse of this was observed in the case of crossbred pigs. The level of cortisol (p<0.05) and testosterone (p<0.01) was higher in crossbred sows than gilts in both serum and FF.

Conclusion:

The study revealed that serum level of the steroid and metabolic hormones is indicative of their level in the ovarian FF. Further, varying level of steroid and metabolic hormones in pigs based on genetic background may be due to variation in body size, rate of energy metabolism and stage of (re)productive life.

Living with the Elekta Compact: Limitations and ways around them

Elekta AB, Sweden has recently propagated the Elekta Compact--a low-cost, small-footprint, single energy (6MV), linear accelerator, in India. The absence of electron beams and the inability to seamlessly deliver inverse planned intensity modulated radiotherapy (IMRT) segments, mean that some out-of-the-box thinking is mandatory for the full range of required treatments in different clinical settings, but is ultimately very rewarding. Our department started off in July 2011, with the Elekta Compact, equipped with MLCi2 and a camera-based electron portal imaging device. For head-neck cancers, we have successfully utilized a 3D conformal class-solution of eight-to-nine oblique beams, with multiple segments, to deliver an adequate dose to the posterior neck, respecting spinal cord tolerance. Parotid gland sparing is possible in selected node-negative hypopharyngeal/laryngeal cancers. For prostate cancers, we have developed a forward-planned IMRT protocol to routinely deliver 76-80 Gy to the prostate, with margins, while conforming to the same rectal dose-volume constraints as in inverse IMRT. Response and tolerance have been excellent so far. In head-neck cancers, the majority (71%) of patients was locally advanced; however, complete response was achieved in 75% of the cases. Grade 3 acute toxicities were seen in only 7% of the cases and compliance overall was excellent, with no patients requiring a gap in treatment. We achieved biochemical control in 100% of the prostate cancer patients; no patients had grade 3 acute toxicities, and with a median follow-up of 12 months, have yet to see any late rectal bleeding. Although engineered for simplicity and versatility, the Compact requires some innovative thinking by clinicians/physicists to optimize the full range of its possibilities. However, upgrades like inverse IMRT delivery, which are in the pipeline, are urgently needed for it to be viable, especially in a single-accelerator department.

Dosimetric comparison between conventional and conformal radiotherapy for carcinoma cervix: Are we treating the right volumes?

Background and Purpose:

Conventional portals, based on bony anatomy, for external beam radiotherapy for cervical cancer have been repeatedly demonstrated as inadequate. Conversely, with image-based conformal radiotherapy, better target coverage may be offset by the greater toxicities and poorer compliance associated with treating larger volumes. This study was meant to dosimetrically compare conformal and conventional radiotherapy.

Materials and Methods:

Five patients of carcinoma cervix underwent planning CT scan with IV contrast and targets, and organs at risk (OAR) were contoured. Two sets of plans-conventional and conformal were generated for each patient. Field sizes were recorded, and dose volume histograms of both sets of plans were generated and compared on the basis of target coverage and OAR sparing.

Results:

Target coverage was significantly improved with conformal plans though field sizes required were significantly larger. On the other hand, dose homogeneity was not significantly improved. Doses to the OARs (rectum, urinary bladder, and small bowel) were not significantly different across the 2 arms.

Conclusion:

Three-dimensional conformal radiotherapy gives significantly better target coverage, which may translate into better local control and survival. On the other hand, it also requires significantly larger field sizes though doses to the OARs are not significantly increased.

Optimized point dose measurement for monitor unit verification in intensity modulated radiation therapy using 6 MV photons by three different methodologies with different detector-phantom combinations: A comparative study

The study was aimed to compare accuracy of monitor unit verification in intensity modulated radiation therapy (IMRT) using 6 MV photons by three different methodologies with different detector phantom combinations. Sixty patients were randomly chosen. Zero degree couch and gantry angle plans were generated in a plastic universal IMRT verification phantom and 30×30×30 cc water phantom and measured using 0.125 cc and 0.6 cc chambers, respectively. Actual gantry and couch angle plans were also measured in water phantom using 0.6 cc chamber. A suitable point of measurement was chosen from the beam profile for each field. When the zero-degree gantry, couch angle plans and actual gantry, couch angle plans were measured by 0.6 cc chamber in water phantom, the percentage mean difference (MD) was 1.35%, 2.94 % and Standard Deviation (SD) was 2.99%, 5.22%, respectively. The plastic phantom measurements with 0.125 cc chamber Semiflex ionisation chamber (SIC) showed an MD=4.21% and SD=2.73 %, but when corrected for chamber-medium response, they showed an improvement, with MD=3.38 % and SD=2.59 %. It was found that measurements with water phantom and 0.6cc chamber at gantry angle zero degree showed better conformity than other measurements of medium-detector combinations. Correction in plastic phantom measurement improved the result only marginally, and actual gantry angle measurement in a flat- water phantom showed higher deviation.

Intestinal mantle cell lymphoma recurring at laparotomy scar region

Mantle cell lymphoma (MCL) is a moderately aggressive variety of non-Hodgkins lymphoma. Extranodal presentation of MCL is well known, the intestine being a common site. The incidence of colorectal involvement is relatively rare. Moreover, the recurrence of the disease at laparotomy scar site is even more rare. We report an unusual case of incision line recurrence in a case of colonic MCL occuring three years after initial treatment.

Comparative study of efficacy and toxicities of cisplatin vs vinorelbine as radiosensitisers in locally advanced head and neck cancer

Introduction:

Currently, concomitant chemoradiation using cisplatin is one of the standards of care for the management of head and neck cancer, but at the cost of increased acute toxicity. Our aim was to assess whether vinorelbine was less toxic and of at least comparable efficacy, if not better, compared with cisplatin.

Materials and methods:

A total of 72 patients with squamous cell carcinoma in the head and neck region were recruited, 40 in arm A and 32 in arm B. Patients in arm A received 40 mg/m2 cisplatin weekly. Patients in arm B received 6 mg/m2 vinorelbine weekly. Both arms also received 66 Gy of radiation in conventional fractionation.

Results and analysis:

There was no statistically significant difference in response rate or toxicities between the two arms, except for nausea and/or vomiting, which was significantly less frequent in the vinorelbine arm.

Conclusion:

Vinorelbine was as effective as cisplatin in controlling locoregional disease in locally advanced head and neck cancer, but was only marginally less toxic than cisplatin.

Evaluation of results of radiotherapy alone vs combined surgery and postoperative radiotherapy in carcinoma external auditory canal-10 years review

Forty-one patients of external auditory canal (EAC) cancer attended the Department of Radiotherapy (RT), Medical College Hospital, Kolkata during the period from 1987 to 1996. Majority were above 50 years of age with slight female preponderance. Out of 41 patients 36 patients completed the full course of treatment of which 12 patients underwent combined modality treatment (RT 50-55 Gy plus surgery) and 24 patients received primary RT alone (55-60 Gy). Radiation therapy was given in standard fractionation schedule. Retrospective analysis revealed complete response in 8/12 (66.7%) in combined modality treatment group and in 3/24 (12.5%) in RT alone group. The actuarial 2 year survival was 19%. following RT alone, 85% following combined modality, 70% in early lesions and 18% in advanced lesions. The study suggests, surgical resection followed by postoperative irradiation is an effective method and better treatment option than RT alone as primary treatment modality for carcinoma of EAC.

Probing the pore of the auditory hair cell mechanotransducer channel in turtle

Hair cell mechano-electric transducer (MET) channels play a pivotal role in auditory and vestibular signal detection, yet few data exist regarding their molecular nature. Present work characterizes the MET channel pore, a region whose properties are thought to be intrinsically determined. Two approaches were used. First, the channel was probed with antagonists of candidate channel subtypes including: cyclic nucleotide-gated channels, transient receptor potential channels and gap-junctional channels. Eight new antagonists were identified. Most of the effective antagonists had a partially charged amine group predicted to penetrate the channel pore, antagonizing current flow, while the remainder of the molecule prevented further permeation of the compound through the pore. This blocking mechanism was tested using curare to demonstrate the open channel nature of the block and by identifying methylene blue as a permeant channel blocker. The second approach estimated dimensions of the channel pore with simple amine compounds. The narrowest diameter of the pore was calculated as 12.5 +/- 0.8 A and the location of a binding site approximately 45% of the way through the membrane electric field was calculated. Channel length was estimated as approximately 31 A and the width of the pore mouth at < 17 A. Each effective antagonist had a minimal diameter, measured about the penetrating amine, of less than the pore diameter, with a direct correlation between IC(50) and minimal diameter. The IC(50) was also directly related to the length of the amine side chains, further validating the proposed pore blocking mechanism. Data provided by these two approaches support a hypothesis regarding channel permeation and block that incorporates molecular dimensions and ion interactions within the pore.

Walking in a vacuum-assisted socket shifts the stump fluid balance

Gains in stump volume have been documented in trans-tibial amputees while walking in custom made under-sized, total surface-bearing, vacuum-assisted sockets (Board et al., 2001). These gains raised doubts as to whether the sockets were truly under-sized and concerns that using an over-sized socket with vacuum-assist could lead to swelling, resulting, in discomfort or pain. The purposes of the present study were to determine if: (a) walking in a vacuum-assisted socket causes the stump to retain or gain volume in excess of the available socket volume and (b) the resulting increase in stump volume with an over-sized socket causes discomfort, pain, and/or the skin to redden. The results of this study showed the stump retained or gained volume in excess of the available socket volume while walking in vacuum-assisted sockets of various sizes. The stump lost less volume than predicted, or gained volume, in under-sized sockets. It also gained more volume than predicted in over-sized sockets. No discomfort, pain, or skin reddening, resulting from the volume gain was reported by any of the subjects after walking in an over-sized socket. This change in fluid balance towards a net gain supports the findings by Board et al. (2001) that vacuum-assist ensures a good fit during the day in ambulatory trans-tibial traumatic amputees with mature stumps.

Apoptosis in batch cultures of Chinese hamster ovary cells

One of the main problems in the culture of Chinese Hamster Ovary (CHO) cells continues to be the inability to maintain the viability of the cultures over an extended period of time. The rapid decline in viability at the end of the culture is exacerbated by the absence of serum. In trying to reduce the extent of death in these cultures, we first tried to determine the mode of death. We found that more than 80% of the cells in a standard serum-free batch culture of CHO cells in suspension died via apoptosis--as evidenced by condensed chromatin and the appearance of a characteristic DNA ladder. Furthermore, when protein synthesis was inhibited using cycloheximide, the cells underwent rapid apoptosis indicating that death proteins were present in greater abundance than survival proteins in our CHO cells. Cell lysate from CHO cells showed evidence of cysteine protease (caspase) activity. Caspases of the Interleukin-1-beta-Converting Enzyme (ICE) family, e.g., CPP32, Mch-1, etc., have been implicated in the apoptotic process. Surprisingly, a caspase peptide inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoro-methyl-ketone (z-VAD.fmk), was unable to substantially extend the life of a serum-free batch culture of CHO cells. In addition, z-VAD.fmk was only marginally able to extend viability in response to withdrawal of growth and survival factors, insulin and transferrin. In both these instances, z-VAD.fmk was able to prevent cleavage of caspase substrates, but not protect cells from death. However, we found that bcl-2 expression was able to significantly extend viabilities in CHO batch culture. Bcl-2 expression also substantially extended the viability of cultures in response to insulin and transferrin withdrawal. These results provide interesting insights into the pathways of death in a CHO cell.

Treatment of molluscum contagiosum in males with an analog of imiquimod 1% in cream: a placebo-controlled, double-blind study

The objective of this double-blind, placebo-controlled study was to evaluate in males the clinical efficacy in treating molluscum contagiosum and tolerance of an analog of imiquimod (1%) in cream. One hundred patients between 9 and 27 years of age (mean 16.3), with 733 lesions (mean 7.3), whose size ranged from 2 to 5 mm diameter (mean spot size 3.4 mm) and a biopsy-confirmed diagnosis of molluscum contagiosum were randomized into two parallel groups. In a double-blind manner, precoded 40-g tubes were dispensed. Patients self-administered the trial medication to their lesions at home three times daily for five consecutive days per week. The study was scheduled with 4 weeks of active treatment (maximum 60 topical applications) and 12 months (on a monthly basis) of follow-up. Patients were examined on a weekly basis. Thirteen patients had atopic dermatitis. A clinically and histopathologically confirmed total elimination of lesions was considered as cured. After four weeks of treatment, 49 patients and 372 lesions were cured. Breaking the code revealed that imiquimod cream had cured 82% of the patients and 86.3% of the lesions. Placebo cleared 16% of the patients and 63 of the lesions (p < 0.0001). During the treatment, 88% of the patients experienced no allergic, localized, or drug-related adverse symptoms. Twelve patients, predominantly in the imiquimod cream group reported non-objective, drug-induced, mild reactions with no dropouts. The study was followed-up for 12 months. Among 49 cured patients, 3 had relapses after 10 months. In conclusion, the study demonstrated that 1% imiquimod analog in cream with mild subjective side effects is significantly more efficacious than the placebo in curing molluscum contagiosum in males.

Splenic enzyme systems as affected by hypothyroidism during pregnancy

Influence of thyroid hormones on splenic activities and the role of the spleen during pregnancy were not known. The present study revealed that increased enzyme activities of spleen are associated with pregnancy, and hypothyroidism during gestation led to decreased activities, indicating that the thyroid gland influences them.

Effect of pregnancy and thyroidectomy on the rat spleen

Pregnancy caused a significant increase (P less than 0.001) in the ascorbic acid and cholesterol concentrations in the spleen as compared to the controls, indicating a rise in its metabolic functions. When thyroid gland was removed either from the non-pregnant animals or at different stages of gestation from pregnant animals, there were significant (P less than 0.001) fall in the levels of these biochemical parameters as compared to the corresponding intact groups. These findings indicated that splenic functions undergo certain changes during pregnancy and the thyroid hormones significantly influence them.